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Research on Police Worn Body Cameras.

Final Project.

Student’s Name:
Institutional Affiliation:

Professor’s Name:



The research proposal scrutinizes the efficacy of using body cameras by police to reduce excessive use of force when incidences occur. Given the frequency at which incidences occur in society, it is vital to understand how to limit the use of force. The research project intends to find out if using body cameras by the police affects how they handle incidents. Earlier research has provided inconsistent results on the effectiveness of police using or not using body cameras in attempts to reduce the force used as they carry out their duties.

According to Simmons, in a research conducted to study police officers with body cameras, a modest but significant reduction was found in their use of force when handling incidents (2014). Additionally, in his research, he concluded that the use of BCWs had a reduced amount of force used when handling suspects to some extent (2014). Rosenthal, (2016), however, found out that officers, even without the use of BCWs, had a significant reduction in their use of force in their daily activities.

The current knowledge in this field is limited because the results from the researches carried out are not consistent. Incidences occurring on the line of duty thus needs further research before a conclusion can be arrived at. Conducting further research will assess the options available on how using force can be limited while on the line of duty can be checked. This research aims at addressing the limitation and bolstering the current amount of information on this topic. Police officers are the protectors of civilians’ life and property through enforcing laws and regulations and thus it is necessary to determine a method to carry this out without abusing their power. Body-worn cameras by the police may either be effective or not but, they will give a basis of scrutinizing the action of officers while at their duties and the basis of their decisions.

Literature review.

The introduction of BCWs in the police officer was with the expectations of improving the rapport between them and civilians. There was also a bid to increase transparency and integrity in the policing department. The effect of BWCs on police officers differs and researchers in a bid to understand this effect have conducted studies in various police departments and under different settings.

Ariel et al. study in 2016 concluded that force can be used objectively when enforcing the law. These could be instances when the officer was acting in self-defense, protecting the life of an innocent party, or apprehending a suspect resisting arrest. To monitor the use of force, the researchers monitored the conditions that pushed the officer to revert to the use of force and decided when the force used was excessive and inappropriate. They also monitored conditions making the officers regulate their behaviors (Braga et al., 2018).

While several studies showed the beneficial results of using BWCs on the use of force, other studies conducted trials in a controlled environment. Where there was no change in how they were treated, Officers with and without BWCs reacted following the same protocols (Ariel, et al, 2016). These empirical studies thus showed that the use of BWCs had not made any changes nor met the initial expectations (Lum et al. 2019). The controlled and experimental studies thus concluded that BWCs had not affected the use intention and reaction of officers when they use force in the field (Ariel et al. 2016, Braga et al., 2018).

The study aims at testing the effectiveness of the BWCs in the police force based upon the complaints on officers. The BWC is expected to make officers more professional, civil, and, more respectful when dealing with civilians (Ariel et al. 2016). However, some studies have introduced other outcomes upon which the effects of BWCs can be analyzed including Policing activities and judicial outcomes. Policing activities include the number of tickets and warnings given by the officer while judicial outcomes included the use of the BWC footage as evidence admissible to the legal system (Lum et al. 2019).

Some studies have shown that the use of force in the interactions of police and civilians increased even with the use of BWCs, which continue being used by the officers (Ariel et al, 2016; Lum et al, 2019). Further studies, however, showed that there was a reduction in the number of complaints against officers wearing BWCs (Braga et al. 2018). Results of a majority of studies studying the use of BWCs are however very inconsistent especially when the dependent variable used is the complaints filed against officers. Most studies however estimate that the comparison between officers with BWCs and those without on the use of force remains 50-50 when it comes to the use of force.

During the surveys on the effectiveness of BWCs, the perceptions of officers regarding their use were also evaluated. Most of them felt that the technology stepped up the excellence of evidence against criminals, especially when building a permanent record against them (Ariel et al. 2016; Lum et al. 2019). An increase in the total overall law enforcement activities was recorded by two independent studies when officers wore their BWCs (Braga et al. 2018). Ariel et al. (2016) further concluded that officers using BWCs used significantly less force as compared to the other group.

The effectiveness of the BWC is mainly reflected in the complaints against the officer wearing it. An information gap exists in the use of BWCs in the greater context and further on how efficient the technology used is. While most studies target the effects of the use of BWCs, there is a further need to study the changes and consequences resulting from using BWCs to limit the force used by officers.

Objectives of the research.

The study will focus on whether BWCs when used by officers limit their use of force when carrying out their duties. The research will extend the discussion on BWCs by analyzing technology as a tool in the resources used to address using of force by the police, criticisms against the use of BWC.

Research Question and Hypotheses.

The research analyzes recent studies on body-worn camera technology and how it impacts the amount of force that officers use. The study addresses the question; how do body-worn cameras help in minimizing the force used by police officers? To come up with a comprehensive answer to this question, the research further addresses the following questions; is their proof showing that wearing body-worn cameras effectively reduces the number of use of force and complaint cases against police officers. I will hypothesize that officers who wear body cameras use approximately less force than those who don’t. The study hypothesizes that the civilizing effect of BWCs as contemplated by Ariel et al. (2015) is that police wearing body cameras tame their tempers and behaviors, use little force compared to those who do not wear body cameras.

Designing the experiment.

The study is designed under the hypothesis that police wearing body cameras tame their tempers and behaviors and are considerably less aggressive compared to their partners who do not. The main objective is thus to find if the force used by officers wearing body cameras is lower compared to their counterparts who do not. The method of experimenting will mirror that employed at the Wolverhampton to monitor the rate of the use of force by police officers wearing Body Cameras and the complaints lodged against it. The independent factor in the experiment will be the number of complaints filed against the officers, which will be taken to signify excessive use of force, against the number of incidents the officer is involved in. The results from the experiment will not only increase the knowledge in this field but also propose body-worn cameras should be adopted.


The experiment will be carried out in the Dallas Police Department that has about 3000 officers. Every day, the department has about five hundred officers on the street during each shift. The study will analyze the use of force from a constant group of five hundred chosen officers from whom a group of a hundred will be randomly chosen and equipped with body cameras just as in Dover’s and Ariel’s study. The rest of the squad will act as the control group. A chart will be placed on the squad room and the information on the group dispatched to each scene recorded; whether wearing body cameras and how the situation is dealt with. To ensure the integrity of the experiment is maintained, no group shall be dispatched more times than the other unless the crime scene requires a specific response team. In such cases, the results will not be recorded. Additionally, suspects’ comments on their treatment by case officers shall be recorded against the relevant group.


Several limitations may occur as the study is carried out. The mentality of the police officers will be a factor. A way must be found to bring them on board and make them willing participants in the experiment. The other challenge will be acquiring enough devices to monitor police officers. The officers will also need to be randomly checked up on while in the field. The aim of this is to ensure that the protocols of the study are adhered to. Finally, a way shall have to be found to analyze previous data to be used as a baseline to compare the officers’ performance before and when using body cameras (Drover & Ariel, 2015).


Ariel, B., Farrar, W. A., & Sutherland, A. (2019). Correction to: The effect of police body-worn cameras on use of force and citizens’ complaints against the police: A randomized controlled trial. Journal of Quantitative Criminology. https://doi.org/10.1007/s10940- 019-09423-y

Ariel, B., Sutherland, A., Henstock, D., Young, J., Drover, P., Sykes, J., Megicks, S., & Henderson, R. (2016). Report: increases in police use of force in the presence of body-worn cameras are driven by officer discretion: a protocol-based subgroup analysis of ten randomized experiments. (Report). Journal of Experimental Criminology, 12(3), 453–463. https://doi.org/10.1007/s11292-016-9261-3

Braga, A., Sousa, W., Coldren, J., & Rodriguez, D. (2018). THE EFFECTS OF BODY-WORN CAMERAS ON POLICE ACTIVITY AND POLICE-CITIZEN ENCOUNTERS: A RANDOMIZED CONTROLLED TRIAL. Journal of Criminal Law and Criminology, 108(3), 511–538.

Drover, P., & Ariel, B. (2015). Leading an Experiment in Police Body-Worn Video Cameras. International Criminal Justice Review, 25(1), 80–97. https://doi.org/10.1177/1057567715574374

Lum, C., Stoltz, M., Koper, C., & Scherer, J. (2019). Research on body-worn cameras: What we know, what we need to know. Criminology & Public Policy, 18(1), 93–118. https://doi.org/10.1111/1745-9133.12412

Rosenthal, L. (2016). Good and bad ways to address police violence. The Urban Lawyer, 48(4), 675–736. (Nunes)

Simmons, K. C. (2014). Body-mounted police cameras: A primer on police accountability vs. privacy. Howard LJ, 58, 881.

Contents lists available at ScienceDirect

Journal of Criminal Justice

journal homepage: www.elsevier.com/locate/jcrimjus


Corrigendum to “A field experiment of the impact of body-worn cameras
(BWCs) on police officer behavior and perceptions” [Journal of criminal
Justice 53 (November 2017) 102–109]

Andrea M. Headleya,⁎, Rob T. Guerettec, Auzeen Shariatib

a John Glenn College of Public Affairs, The Ohio State University, 1810 College Rd., 310L Page Hall, Columbus, OH 43210, United States of America
b Department of Criminal Justice, St. Joseph’s College, 155 W Roe Blvd, O’Connor Hall, E-116, Patchogue, NY 11772, United States of America
c Department of Criminal Justice, Florida International University, 11200 SW 8th St., PCA-366B, Miami, FL 33199, United States of America

In a post hoc review of the data and manuscript by the authors the
following errors were uncovered:

(1) A typographical error was made for the control group’s sample size.
It should read 24 officers in the control group not 25 officers. Thus,
the sample sizes for the control and treatment groups should have
been 24 and 26 respectively (with the treatment group count re-
maining unchanged).

(2) A data management error (of transitioning data between various
statistical software packages) led to an incorrect calculation of ef-
fect sizes using Cohen’s d. Further, the Cohen’s d numbers reported
in Table 3 do not match the effect sizes reported in the final sum-
mary paragraph of section 5.1 on page 106 of manuscript.
Relatedly, the author’s used monthly averages rather than officer
averages to calculate the effect sizes, which masks differences in
sample sizes across treatment and control. Thus, in recalculating the
effect sizes, the authors report the following effect sizes: Arrests
(0.289), Field Contacts (−0.004), Citations (−0.129), Use of Force
(−0.010), Complaints (0.415), Assaults on Officers (0.110), and
Non-Violent Resistance (−0.002). These effect sizes suggest only
one medium effect for complaints, which the authors interpret with
caution due to the low numbers of total complaints.

(3) A coding error led to true zero’s being counted as missing data and
thus multiple imputation was performed on arrests, field contacts,
and citations. However, it is important to note that Table 2 and 3’s
summary statistics were calculated without imputations and thus

remains an accurate reflection of the data. Rather, the imputed data
was used to perform the significance tests, which should not have
been done. In rerunning independent t-test (without imputed data)
to solely account for differences across the post-outcome measures
for the treatment and control groups, there are no longer any sta-
tistically significant results. Similarly, in rerunning paired t-test to
assess changes in only the treatment group’s pre- and post-out-
comes, there were no statistically significant results. However, ra-
ther than analyzing separate t-test, the authors acknowledge that to
properly account for the pre-test-post-test control group design,
examining the amount of change (averaged across officers) from
2015 to 2016 between treatment and control groups using an in-
dependent samples t-test or analysis of variance should have been
conducted. Nevertheless, these tests also produce null results.1

All in all, the new findings suggest that there are no statistically
significant differences in officer outcomes for individuals wearing body
cameras compared to those not wearing body cameras. Thus, the prior
findings regarding statistical significance for officer arrests and field
contacts in particular should be disregarded in light of the corrections
noted above. However, the article’s findings regarding (a) percent
changes and general trends for each of the various outcomes measured,
(b) officer perceptions taken from the officer surveys, and (c) calcula-
tions of officer compliance, have all remained accurate. The authors
apologize for any inconvenience this caused and hope the updated
findings may be of use to the evidence base on body-worn cameras.


DOI of original article: https://doi.org/10.1016/j.jcrimjus.2017.10.003
⁎ Corresponding author.
E-mail addresses: [email protected] (A.M. Headley), [email protected] (R.T. Guerette), [email protected] (A. Shariati).

1 As a post hoc analysis, regressions (using analysis of covariance) were assessed and included a covariate-by-group interaction term to account for potential
heterogenous or unequal regression slopes (following suit of prior studies such as Ratcliffe et al., 2011). For two key outcomes, arrests and citations, statistically
significant findings for the interaction terms suggested that the slope of the pretreatment arrests and citation levels varied by treatment and control groups. However,
the authors refrain from relying on and interpreting these results seeing as the other primary analyses produced null results and due to potential outliers driving the
interaction effects.

Ratcliffe, J. H., Taniguchi, T., Groff, E. R., & Wood, J. D. (2011). The Philadelphia foot patrol experiment: A randomized controlled trial of police patrol effec-
tiveness in violent crime hotspots. Criminology, 49(3), 795–831.

Journal of Criminal Justice 68 (2020) 101690

Available online 13 May 2020
0047-2352/ © 2017 Elsevier Ltd. All rights reserved.


  • Corrigendum to “A field experiment of the impact of body-worn cameras (BWCs) on police officer behavior and perceptions” [Journal of criminal Justice 53 (November 2017) 102–109]


Critical Social Policy 1–20
© The Author(s) 2021
DOI: 10.1177/02610183211033923

Article reuse guidelines: sagepub.com/journals-permissions

Body-worn cameras, police
violence and the politics of
evidence: A case of ontological

The Australian National University, Australia

University of Waterloo, Canada

The Australian National University, Australia

Public demands for greater police accountability, particularly in relation
to violence targeting Black and Brown communities, have placed pressure
on law enforcement organisations to be more transparent about offic-
ers’ actions. The implementation of police body-worn cameras (BWCs)
has become a popular response. This article examines the embrace of
BWCs amidst the wider shift toward evidence-based policing by scrutinis-
ing the body of research that evaluates the effects of these technolo-
gies. Through an intertextual analysis informed by insights from Critical
Race Theory and Science and Technology Studies, we illustrate how the
privileging of certain forms of empiricism, particularly randomised con-
trolled trials, evinces what Woolgar and Pawluch describe as ontological
gerrymandering. In doing so, the emergent evidence base supporting
BWCs as a policing tool constitutively redefines police violence into a

Corresponding author:
Kathryn Henne, The Australian National University, Canberra, 2600, Australia.
Email: [email protected]

1033923CSP0010.1177/02610183211033923Critical Social PolicyHenne et al.


2 C r i t i c a l S o c i a l P o l i c y 00(0)

narrow conceptualisation rooted in encounters between citizens and
police. This analysis examines how these framings, by design, minimise
racialised power relations and inequalities. We conclude by reflecting
on the implications of these evidence-based claims, arguing that they
can direct attention away from – and thus can buttress – the structural
conditions and institutions that perpetuate police violence.

Key words
evidence-based policy, knowledge production, police body-worn
cameras, police violence, racism


Demands for radical changes in policing gained significant momentum in
2020. A wave of protests ensued across the United States and globally after
a white police officer killed George Floyd, an unarmed Black man arrested
by Minneapolis police for allegedly using a counterfeit 20-dollar bill. It also
reignited outrage about police killings of other unarmed people of colour. In
response, a range of proposals emerged, including calls to defund the police
and to abolish militarised law enforcement practices, as well as recommenda-
tions to implement stronger police accountability measures.

Against this backdrop, police organisations across the United States have
implemented police body-worn cameras (BWCs) to improve police behaviour
and accountability. Other countries have followed suit, investing significantly
in the technology. In June 2020, Canadian Prime Minister Justin Trudeau
addressed the issue of racialised police violence by promising to work quickly
with provinces to introduce BWCs among Canadian police organisations
(Blanchfield, 2020). Officers in jurisdictions as diverse as Australia, China,
Turkey, the United Kingdom, and Uruguay wear BWCs while on patrol.
Despite the widespread use of BWCs, debates continue regarding their merits
as a solution to police violence and whether funds might be better spent on
social programs. While advocates have framed them as a promising ‘evidence-
based’ response to demands for police reform (e.g., Ariel et al., 2017a; Cubitt
et al., 2017), critics have argued BWCs threaten individual privacy (Lippert
and Newell, 2016), broaden state control (Adams and Mastracci, 2017), and
disproportionately target racialised communities (Bud, 2016; Mateescu et al.,

The proliferation of police BWCs has been matched with a steady rise in
studies assessing the effectiveness of the technology in reducing officer mis-
conduct and improving police accountability. It reflects a trend, often referred
to as ‘evidence-based policing’, that promotes empirical evaluations of ‘what
works’ to enhance policing practice and ensure cost-effectiveness (Sherman,

H e n n e e t a l . 3

2013). Although some policymakers propose rigorous and objective research
as a mode of counteracting the shortcomings of experts and practitioners
(Pearce and Raman, 2014), evidence-based policies are not as politically
neutral as inferred. As ‘evidence is constructed and used to make decisions’
through ‘socially organised practices’ (Nichols, 2017: 605), it would be a mis-
take to assume it is resistant to influence. Governments often use evidence ‘to
transform ideology into discourse, which then provides the legitimate author-
ity to force through the intended reform agenda’ (Naughton, 2005: 47). The
joining of evidence and policy can therefore reinforce state interests. In the
case of criminal justice policy, there is not only a ‘lack of diversity among the
voices represented as experts on crime’ (Uggen and Inderbitzin, 2010: 734),
but also a ‘troubling lack of attention to power and power relations’ that
perpetuate inequalities, forms of oppression, and processes of criminalisation
(Nelund, 2014: 68).

Accordingly, scholars have questioned the scientific standards upon which
many evidence-based policies are based, indicating they are poorly equipped
to examine inequality – or, worse, are implicated in imperialistic practices.
As Kitossa (2014: 63) explains, the ‘pretensions of scientific rationalism’ can
reinforce and perpetuate ‘epistemic violence’, especially as positivistic evi-
dence is often used to disqualify claims made by colonised and minoritised
peoples. Considering these observations, we take up Science and Technology
Studies (STS) scholars’ calls to critically examine practices of evidence-based
policy through the lens of epistemic governance – which ‘suggests that the
production of knowledge for governance itself needs be governed’, not simply
embraced without question (Pearce and Raman, 2014: 388). In examining
assessments of BWCs’ effectiveness, we bring concerns of epistemic gover-
nance in dialogue with longstanding critiques that mainstream criminology’s
value-neutral claims reflect the field’s complicity in enabling government
and corporate entities to advance unjust forms of domination and violence
(Young, 2012).

We explore how the emergent BWC evidence base constitutively informs
policy-related understandings of police violence, which Critical Race Theory
(CRT) scholars have traced as a ‘structural phenomenon and not simply as a
product of rogue police officers who harbour racial animus’ (Carbado, 2016:
1482). As documented in this article, many evidence-based interventions
adopt a different approach; they frame the social problem of police violence
as police misconduct, which captures law enforcement officer ‘behaviour that is
deviant, dishonest, improper, unethical, and criminal’ (Roebuck and Barker,
1974, cited in Maule, 2017: 9). In doing so, their work exemplifies a form of
ontological gerrymandering, a process that Woolgar and Pawluch (1985: 216)
describe as ‘portraying statements about conditions and behaviours as objec-
tive while relativising the definitions and claims made about them’. Accord-
ing to Woolgar and Pawluch (1985), even constructivist efforts to explain

4 C r i t i c a l S o c i a l P o l i c y 00(0)

social problems often conceptualise societal issues as if they are stable. By
missing opportunities to query how these definitions are socially contingent,
they can reinforce problematic power dynamics. Here, we argue that evalu-
ations of BWCs offer a contemporary case of ontological gerrymandering,
which is informed by the rise of evidence-based policing. Their methodologi-
cal approaches recast police violence as localised phenomena, obscuring how
interlocking oppressions contribute to this wider social problem. In failing
to shed light on structural conditions contributing to police violence, this
body of knowledge lends to policy interventions that retain an individualistic
and behavioural focus, such as anti-bias training or BWCs, rather than more
substantive changes.

Our argument proceeds as follows: First, we situate the uptake of BWCs
within a broader call for evidence-based policies and policing reform. We
then reflect on our approach and methods of analysis, explaining how we
draw on both CRT and STS to scrutinise how evidence-based claims are fash-
ioned and justified. The third section of the article details how evaluations of
BWCs’ effectiveness come to constitutively redefine police violence into an
issue of police misconduct. We conclude with a critical discussion of how this
instance of ontological gerrymandering reflects hegemonic standards of evi-
dence and how they threaten to contribute to the ongoing problem of police

Situating BWC debates and the rise of evidence-
based policing

The implementation of BWCs as devices intended to support police reform
fits within a longer trajectory of police surveillance (see Bradford et al., 2020).
While various technologies and techniques, including the use of informants,
biometric verification, and predictive policing tactics, are geared toward mon-
itoring citizens, other surveillance technologies have been deployed for the
stated purpose of tracking officers. For example, US legislation implementing
dashboard cameras responded to civil unrest following documented instances
of police racial bias during the 1980s. In-car cameras emerged as a solution by
recording whether police received consent to search stopped vehicles and are
still used to monitor police-citizen interactions during routine traffic stops
(Morton, 2018). Many contemporary police cruisers are equipped with Global
Positioning Systems (GPS) that use real-time locations to track officers and
vehicles (Mabrey, 2003), as well as microphones, affixed to officers or vehi-
cles, to ‘create an audible record of events as they happen’ (IACP, 2004: 48).
More recently, BWCs have been promoted to monitor police behaviour. In
2015, the US Department of Justice committed $23 million to BWC pilot
programs in 32 states (Yokum et al., 2019). The uptake of this technology

H e n n e e t a l . 5

by police departments has increased rapidly, with over 90 per cent of police
organisations in major US cities implementing BWCs (Leadership Confer-
ence on Civil and Human Rights and Upturn, 2017).

BWC technology consists of a small battery-powered wearable camera
affixed to an officer’s uniform, typically on the upper chest or shoulder area
(though sometimes worn on their hat or sunglasses). When turned on, the
camera records audio and video footage from the vantage point of the offi-
cer wearing it, which is then stored either locally on a server managed by
the police organisation or remotely on a cloud database managed by a third-
party vendor (Hung et al., 2016). Despite minor differences in video quality
and data storage options, the technology itself is relatively standard in form
(Brustein, 2018). BWC policy and procedure, however, varies considerably
among police organisations. For instance, some organisations require officers
equipped with BWCs to keep the camera always activated, while others allow
officers to activate the camera at their discretion (Hung et al., 2016). Newer
camera models are automatically activated when officers draw a weapon or
turn on emergency lights in their cruisers, at which point the body cam foot-
age is livestreamed to police supervisors (Axon Enterprise, Inc., n.d.). At the
time of writing, no overarching legislation in North America regulates how
and when BWC footage is publicly released by police.

While the embrace of BWCs is presented as a response to public demands
for increased police accountability and transparency, it also coincides with
the rise of evidence-based policing. Evidence-based policing advocates for
policies and practices that have been investigated and assessed as effective
– typically through experimental methods. Some police researchers have
argued evidence-based reforms are the most appropriate response to critical
issues like fatal police-citizen encounters (Engel et al., 2020). Other scholars
beyond criminology have criticised evidence-based solutions on the grounds
that their design ‘imposes very stringent requirements on quality of data,
randomisation, and replication’, often to the exclusion of socially meaningful
categories of difference and contextual nuance (Willis and White, 2003, as
cited by valentine 2009: 449).

To date, most evidence-based studies of BWCs employ randomised con-
trolled trials (RCTs) designed to isolate the causal effect of the technology on
a specific outcome, such as police use of force. Many of them draw conclusions
about BWCs’ positive impacts (e.g., Ariel et al., 2017a; Demir, 2019; Suther-
land et al., 2017; White et al., 2018). Some assessments cast doubt on these
assertions (Yokum et al., 2019), characterising the effects of BWCs as unclear
(Yokum et al., 2019). Others contend that important questions remain unan-
swered, such as whether BWCs mitigate officers’ unfair treatment of citizens
across social categories of difference, such as class, ethnicity, gender, race, and
religion (Lum et al., 2015; 2019).

By focusing on the quality of evidence, criminologists involved in these
debates often fail to ask whether or how the pursuit of more or better BWC

6 C r i t i c a l S o c i a l P o l i c y 00(0)

evidence will result in reducing police violence. They also negate the short-
comings of past evidence-based policing approaches. For instance, hot spots
policing is a widely implemented set of policing tactics, which is backed
by experimental evidence suggesting it has crime deterrence effects (Sher-
man and Weisburd, 1995: 645). Critics note that these findings about hot
spots policing ‘fail to consider implications beyond the immediate crime
effects’ (Kochel, 2011: 367), including the violence that police dispropor-
tionately inflict on predominately Black and Brown communities (Gaston
et al., 2020). Acknowledging these patterns, critical criminologist Schneider
(2018) explains that the promotion of police BWCs is not about accountabil-
ity. Accountability would entail ‘an obligation to give an account of activities
within one’s ambit of responsibility’; rather, he argues, the introduction of
BWCs is about building ‘the capacity to provide a record of activities that
explains them in a creditable manner so that they appear to satisfy the rights
and obligations of accountability’ (Ericson, 1995: 137, cited in Schneider,
2018: 459). Thus, we ask: what assumptions and values are embedded in
assessments of BWCs and their impacts on policing?

Using CRT and STS to illuminate ontological

To examine the assumptions underpinning empirical assessments of BWCs’
effectiveness, we draw on CRT and STS, two fields of critical inquiry that
offer valuable insights for interrogating questions of exclusion, expertise, and
knowledge. CRT has a rich tradition of laying bare the normalisation of rac-
ism (Delgado and Stefancic, 2017), with a strong emphasis on how legal and
social forces contribute to ‘an ongoing, dialectic process that ultimately repro-
duces and transforms racial inequality’ (Gómez, 2010: 448). We also draw on
STS, particularly feminist science studies, because it provides complementary
modes of examining power exercised through ‘epistemological and ontologi-
cal assumptions’ (Foster, 2016: 129). Comprised of scholars who are diverse
in their perspective and substantive interests, feminist science studies scholar-
ship interrogates how ‘the cloak of “pure science” and objectivity continues
to surround the sciences’ (Subramaniam, 2009: 952). CRT thus provides the
‘methodological guideposts that challenge mainstream assumptions about
objective research and interpretation’ (Christian et  al., 2019: 5), while STS
offers analytic tools for unpacking the epistemic politics of evidence-based
claims in practice (Pearce and Raman, 2014).

Methodologically, we carried out an in-depth analysis of a sample col-
lected through an earlier study that systematically reviewed the English
literature on police-issued surveillance technologies and police misconduct
(Henne et al., 2020). Here, we examined how evaluative research assesses the

H e n n e e t a l . 7

effectiveness of BWCs and then queried two dimensions of their claims: (1)
what comes to count as evidence and (2) how they, in turn, conceive of the
social problem addressed by BWCs. Having had read nearly 1,400 BWC
research studies for our earlier systematic review (N=1,397), we focused this
analysis on articles that assessed BWCs specifically in relation to police mis-
conduct. Notable themes emerged through the process: Most studies exam-
ined US contexts, employed RCTs in their design and used either official
complaints against police or police perceptions of behaviour as measures of
police misconduct. Despite making a range of evidentiary claims, a limited
number of studies met positivistic evidenced-based criteria (N=21). Our
examination revealed methodological inconsistencies and highlighted how
positivistic methodologies exclude important social considerations.

In keeping with other STS analyses, such as Woolgar and Lezaun (2013:
330−331), we examined how the ‘organisation of texts’ provided insight into
‘the relations of governance with respect to ordinary objects’, such as the sci-
entific variables that are central within positivistic reasoning. Employing an
intertextual analysis enabled close examination of scientific claims and the
power dynamics informing them (Henne and Shah, 2015; Nichols, 2017).
This approach facilitated a close reading of the language, rationales and ideol-
ogies employed when explaining findings across publications. We identified
patterns in the construction and explanation of evidence. The process, in turn,
illuminated how textual relationships instil and reflect acts ‘of control’ from
which ‘the issue of social power arises’ (Briggs and Bauman, 1990: 76). This
level of scrutiny enabled tracing the logics underpinning authors’ descrip-
tions of whether and how results in the sample met standards of evidence.

The intertextual analysis also aided in identifying patterns that reflected
conventions in the field of criminology, which have been characterised as
disregarding or minimising the role of race and racism in shaping under-
standings of criminality (see Henne and Shah, 2015; Van Cleve and Mayes,
2015). Like other empirical CRT approaches, we sought to understand how
‘research design is rarely race-neutral’; the ‘selection of an analytical object’,
measurement techniques, ‘the choice of method’ and ‘empirical foci are inevi-
tably shaped by political concerns’ (Christian et al., 2019: 2). Van Cleve and
Mayes (2015: 420−421), for instance, argue, ‘Criminal justice research and
statistics play a crucial role in the cultural reification of Black criminality’
because these ‘[s]eemingly race-neutral statistics’ are understood as ‘scientific
proof. . . and justification for support of practices and policies that reinforce
racial segregation and inequality’. Building on their observations, we exam-
ined how similar dynamics emerged in the framing of BWC evidence.

Accounting for textual alignments and divergences across the studies
enabled us to analyse the constitutive relationships that substantiate authors’
claims, including their research design decisions, choice of variables, modes of
assessment and linguistic characterisations. In the next sections, we detail how

8 C r i t i c a l S o c i a l P o l i c y 00(0)

claims about BWCs come to reflect a narrow gaze that is limited to particular
and often isolated factors related to police-citizen encounters. Their construc-
tions of BWCs and police violence as objects of analysis share a common ten-
dency: they overlook the socially contingent dimensions of these interactions
and erase structural factors that could – and arguably should – inform policy.

Techniques of constructing BWC evidence

Evaluating BWCs does more than measure the impact of these technologies
on policing; it entails a process of constructing objects for analysis. Positivistic
logics and criteria conceive of BWCs as independent entities, with most stud-
ies reflecting two key tendencies. First, they focus on the localised encounter
between law enforcement officers and citizens as the source for understanding
police violence, and second, they reflect a presumption that actively monitor-
ing police officers can change behaviour. This epistemological vantage point
implicates how both police violence and BWCs are constructed in the produc-
tion of evidence-based claims.

To understand these constitutive dynamics first requires considering the
mainstays of evaluation research and hierarchies of evidence. RCTs are consid-
ered effective in assessing whether a specific intervention produces an intended
effect and are common in medicine; however, the ‘lay public, and sometimes
researchers, put too much trust in RCTs over other methods of investigation’
(Deaton and Cartwright, 2018: 2). RCTs neglect ‘issues of interpretation and
meaning in the desire to tame complexity with numbers’ and fail ‘to consider
ethical questions around random assignment of potentially beneficial inter-
ventions’ (Pearce and Raman, 2014: 389) – both of which are important for
many areas of policymaking. They may advance science, but they are weak
grounds for understanding ‘what works’ because they cannot capture dynamic
social interactions (Deaton and Cartwright, 2018; see also Cartwright, 2007).

BWC evaluation research’s privileging of RCTs reflects these limitations.
Most studies analysed in our sample present their aims as assessing BWCs’
impact on actions, such as reducing use-of-force and complaints. As such,
they reinforce a presumption that BWCs’ successes or failures (e.g., to reduce
force or not reduce force) can be understood as consistent interventions, even
if the context, situation, and actors involved vary greatly. In other words,
BWCs become understood as entities used by human actors to do policing
in methodical and predictable ways, rendering BWC technology as a thing
abstracted from context. This depiction emerges in sharp contrast to STS
approaches, which would acknowledge an object, including BWCs, as part of
entangled relationships (Henne and Harb, 2020; Woolgar and Lezaun, 2013).

The problematic dimensions of these framings become evident when
scrutinising what considerations are removed when making empirical assess-

H e n n e e t a l . 9

ments that align with objective criteria. To illustrate, let us look more closely
at an exemplar of these analyses: Ariel and colleagues (2017a: 303) claim
that BWCs reduce complaints against police and can therefore aid in improv-
ing police legitimacy. They reason that the presence of BWCs conveys to
everyone involved in a police-citizen interaction that they are being recorded;
this knowledge – and the subsequent potential that one’s behaviour can later
be scrutinised – improves the behaviour of all parties. The authors suggest
this dynamic reduces complaints made against police in two ways: first,
BWCs reduce legitimate complaints against police by serving as a catalyst for
improved police behaviour, and, second, BWCs dissuade illegitimate com-
plaints from citizens who want to ‘make trouble’ (Ariel et al., 2017a: 302).

While this example captures what is described as the ‘civilising effect’ of
BWCs (see Headley et al., 2017), it departs from observations made through
different modes of inquiry. Others have documented how BWC footage,
especially when combined with officer accounts of events, often undermines
the credibility of citizen narratives about police violence (Brucato, 2015;
Russell-Brown, 2016). By buttressing police explanations, BWCs can oper-
ate as repressive tools against citizens seeking to make claims against law
enforcement officers (Brucato, 2015). Further, RCTs negate how time can
shift behaviour changes that BWCs may initially spark. As police become
more accustomed to BWCs and being recorded, they may adapt their actions,
which is a potential longitudinal development that exceeds the scope of the
RCTs in our sample. Instead, RCTs, by design, divorce their analytic assess-
ments from lived realities of citizen-police encounters, including the social
conditions and inequalities that inform them (Roussell et  al., 2017). Their
narrow focus on the specific ‘act’ and ‘effect’ results in research that does not
capture structural or relational considerations. The civilising effect can thus
be asserted as an evidence-based finding precisely because the methodology
used disregards the on-the-ground relationships of which these technologies
become a part.

Although RCT research is often upheld as the gold standard of evidence
(Cartwright, 2007), many results interpreted as supporting BWCs as a police
reform fail to meet accepted standards of evaluation; that is, they do not
adhere to their own guiding methodological principles. Adherence to strict
positivistic criteria is the very mechanism that allows positivistic researchers
to assert claims as evidence. When studies deviate from their own set criteria,
they – by their own definition – jeopardise the credibility of their results.
While the nature of these limitations varied across the studies, inconsisten-
cies in the definition of officer misconduct was a clear pattern. For example,
many studies include the outcome measure of ‘police use of force’ or ‘official
citizen complaints against the police’. Relying on official citizen complaints
is often problematic, though, as citizens are less likely to come forward with
complaints against law enforcement officers when there are tenuous police-

10 C r i t i c a l S o c i a l P o l i c y 00(0)

community relationships (Gascón and Roussell, 2019; Kappeler et al.,1992).
Studies in our sample also used police perceptions of their own behaviour as
a variable for assessing police misconduct (e.g., Goetschel and Peha, 2017),
which has long been understood as misleading because officers tend to under-
estimate the prevalence of their own misconduct (Hader and Snortum, 1975).
This measure not only reinscribes police misconduct as the primary issue of
concern, but it also lends to conservative, and likely skewed, estimates of
individual behaviour.

Another foundational challenge for RCTs that emerges across the studies
analysed is maintaining the necessary conditions of their experiment, which
require controlled separation of the experimental groups under study (e.g.,
officers with BWCs and officers without BWCs) and accounting for all pos-
sible variables that may influence study results (e.g., officer age, rank). Study-
ing interactions in real-life settings, however, is unpredictable. For example,
it is difficult to verify whether officers in experiments appropriately activate
their BWCs because of two key issues: (1) not knowing for sure whether offi-
cers had their BWCs turned on and (2) keeping officers assigned to wear
BWCs separate from those assigned not to wear BWCs during their encoun-
ters with citizens. From an evaluative stance, the potential co-mingling of
officers wearing BWCs and officers not wearing BWCs during an experiment
prompts questions about whether changes in officer-citizen encounters are
due to the technology or to some other factor – a concern most authors did

Many studies inconsistently adhered to accepted statistical logics. At
times, authors recognised this problem, citing issues with statistical power
due to low incident rates (e.g., White et al., 2018). Others make no note of
the statistical issues afflicting their experiments,2 even though rigour is a
stated justification for RCTs. For instance, a US-based study found no sig-
nificant difference in the number of complaints received by officers wear-
ing BWCs compared to officers not wearing BWCs during their one-year
experiment (Ariel et  al., …

Quoting, Paraphrasing, and Summarizing

This resource was written by Purdue OWL.

Last full revision by Dana Lynn Driscoll.

Last edited by Dana Lynn Driscoll on September 10th 2006 at 11:49AM

Summary: This handout is intended to help you become more comfortable with the uses

of and distinctions among quotations, paraphrases, and summaries. This handout

compares and contrasts the three terms, gives some pointers, and includes a short excerpt

that you can use to practice these skills.

Quoting, Paraphrasing, and Summarizing

This handout is intended to help you become more comfortable with the uses of and

distinctions among quotations, paraphrases, and summaries. This handout compares and

contrasts the three terms, gives some pointers, and includes a short excerpt that you can

use to practice these skills.

What are the differences among quoting, paraphrasing, and


These three ways of incorporating other writers’ work into your own writing differ

according to the closeness of your writing to the source writing.

Quotations must be identical to the original, using a narrow segment of the source. They

must match the source document word for word and must be attributed to the original


Paraphrasing involves putting a passage from source material into your own words. A

paraphrase must also be attributed to the original source. Paraphrased material is usually

shorter than the original passage, taking a somewhat broader segment of the source and

condensing it slightly.

Summarizing involves putting the main idea(s) into your own words, including only the

main point(s). Once again, it is necessary to attribute summarized ideas to the original

source. Summaries are significantly shorter than the original and take a broad overview

of the source material.

Why use quotations, paraphrases, and summaries?

Quotations, paraphrases, and summaries serve many purposes. You might use them to . . .

 Provide support for claims or add credibility to your writing

 Refer to work that leads up to the work you are now doing

 Give examples of several points of view on a subject

 Call attention to a position that you wish to agree or disagree with

 Highlight a particularly striking phrase, sentence, or passage by quoting the


 Distance yourself from the original by quoting it in order to cue readers that the

words are not your own

 Expand the breadth or depth of your writing

Writers frequently intertwine summaries, paraphrases, and quotations. As part of a

summary of an article, a chapter, or a book, a writer might include paraphrases of various

key points blended with quotations of striking or suggestive phrases as in the following


In his famous and influential work On the Interpretation of Dreams, Sigmund

Freud argues that dreams are the “royal road to the unconscious” (page #),

expressing in coded imagery the dreamer’s unfulfilled wishes through a process

known as the “dream work” (page #). According to Freud, actual but unacceptable

desires are censored internally and subjected to coding through layers of

condensation and displacement before emerging in a kind of rebus puzzle in the

dream itself (page #s).

How to use quotations, paraphrases, and summaries

Practice summarizing the following essay, using paraphrases and quotations as you go. It

might be helpful to follow these steps:

 Read the entire text, noting the key points and main ideas.

 Summarize in your own words what the single main idea of the essay is.

 Paraphrase important supporting points that come up in the essay.

 Consider any words, phrases, or brief passages that you believe should be quoted


There are several ways to integrate quotations into your text. Often, a short quotation

works well when integrated into a sentence. Longer quotations can stand alone.

Remember that quoting should be done only sparingly; be sure that you have a good

reason to include a direct quotation when you decide to do so. You’ll find guidelines for

citing sources and punctuating citations at our documentation guide pages.

Paraphrase: Write it in Your Own Words

Paraphrasing is one way to use a text in your own writing without directly quoting source

material. Anytime you are taking information from a source that is not your own, you

need to specify where you got that information.

A paraphrase is…

 Your own rendition of essential information and ideas expressed by someone else,

presented in a new form.

 One legitimate way (when accompanied by accurate documentation) to borrow

from a source.

 A more detailed restatement than a summary, which focuses concisely on a single

main idea.

Paraphrasing is a valuable skill because…

 It is better than quoting information from an undistinguished passage.

 It helps you control the temptation to quote too much.

 The mental process required for successful paraphrasing helps you to grasp the

full meaning of the original.

6 Steps to Effective Paraphrasing

1. Reread the original passage until you understand its full meaning.
2. Set the original aside, and write your paraphrase on a note card.
3. Jot down a few words below your paraphrase to remind you later how you

envision using this material. At the top of the note card, write a key word or

phrase to indicate the subject of your paraphrase.

4. Check your rendition with the original to make sure that your version accurately
expresses all the essential information in a new form.

5. Use quotation marks to identify any unique term or phraseology you have
borrowed exactly from the source.

6. Record the source (including the page) on your note card so that you can credit it
easily if you decide to incorporate the material into your paper.

Some examples to compare

The original passage:

Students frequently overuse direct quotation in taking notes, and as a result they overuse

quotations in the final [research] paper. Probably only about 10% of your final

manuscript should appear as directly quoted matter. Therefore, you should strive to limit

the amount of exact transcribing of source materials while taking notes. Lester, James D.

Writing Research Papers. 2nd ed. (1976): 46-47.

A legitimate paraphrase:

In research papers students often quote excessively, failing to keep quoted material down

to a desirable level. Since the problem usually originates during note taking, it is essential

to minimize the material recorded verbatim (Lester 46-47).

An acceptable summary:

Students should take just a few notes in direct quotation from sources to help minimize

the amount of quoted material in a research paper (Lester 46-47).

A plagiarized version:

Students often use too many direct quotations when they take notes, resulting in too many

of them in the final research paper. In fact, probably only about 10% of the final copy

should consist of directly quoted material. So it is important to limit the amount of source

material copied while taking notes.

Sentence Clarity

This resource was written by Purdue OWL.

Last full revision by Chris Berry.

Last edited by Chris Berry on June 5th 2006 at 4:18AM

Summary: If you’re having sentence clarity problems in your papers, this handout might

be just what you need.

Improving Sentence Clarity

There are many strategies for improving the clarity of your sentences and your papers.

Go from old to new information

Introduce your readers to the “big picture” first by giving them information they already

know. Then they can link what’s familiar to the new information you give them. As that

new information becomes familiar, it too becomes old information that can link to newer


The following example sentence is clear and understandable because it uses old

information to lead to new information:

Every semester after final exams are over, I’m faced with the problem of what

to do with books of lecture notes (new information). They (old) might be useful

some day, but they just keep piling up on my bookcase (new). Someday, it (old)

will collapse under the weight of information I might never need.

Here is a sentence that is not as clear. It moves from new information to old information:

Lately, most movies I’ve seen have been merely second-rate entertainment, but

occasionally there are some with worthwhile themes. The rapid disappearance of

the Indian culture (new) is the topic of a recent movie (old) I saw.

Did you find the second sentence hard to read or understand? If so, it could be because

the old information comes late in the sentence after the new information. A clearer

version that moves from old information to new information might look like this:

Lately, most movies I’ve seen have been merely second-rate entertainment, but

occasionally there are some with worthwhile themes. One recent movie (old) I

saw was about the rapid disappearance of the Indian culture. (new)

Be careful about placement of subordinate clauses

Avoid interrupting the main clause with a subordinate clause if the interruption will cause


clear (subordinate clause at the end):

Industrial spying is increasing rapidly because of the growing use of computers

to store and process corporate information.

clear (subordinate clause at the beginning):

Because of the growing use of computers to store and process corporate

information, industrial spying is increasing rapidly.

not as clear (subordinate clause embedded in the middle):

Industrial spying,because of the growing use of computers to store and process

corporate information, is increasing rapidly.

Use active voice

Sentences in active voice are usually easier to understand than those in passive voice

because active-voice constructions indicate clearly the performer of the action expressed

in the verb. In addition, changing from passive voice to active often results in a more

concise sentence. So use active voice unless you have good reason to use the passive. For

example, the passive is useful when you don’t want to call attention to the doer; when the

doer is obvious, unimportant, or unknown; or when passive voice is the conventional

style among your readers.

clear (active):

The committee decided to postpone the vote.

not as clear (passive):

A decision was reached to postpone the vote.

Use parallel constructions

When you have a series of words, phrases, or clauses, put them in parallel form (similar

grammatical construction) so that the reader can identify the linking relationship more

easily and clearly.

clear (parallel):

In Florida, where the threat of hurricanes is an annual event, we learned that

it is important (1) to become aware of the warning signs, (2) to know what

precautions to take, and (3) to decide when to seek shelter.

not as clear (not parallel):

In Florida, where the threat of hurricanes is an annual event, we learned that

it is important (1) to become aware of the warning signs. (2) There are

precautions to take, and (3) deciding when to take shelter is important.

In the second sentence, notice how the string of “things to be aware of in Florida” does

not create a parallel structure. Also, notice how much more difficult it is for a reader to

follow the meaning of the second sentence compared to the first one.

Avoid noun strings

Try not to string nouns together one after the other because a series of nouns is difficult

to understand. One way to revise a string of nouns is to change one noun to a verb.

unclear (string of nouns):

This report explains our investment growth stimulation projects.


This report explains our projects to stimulate growth in investments.

Avoid overusing noun forms of verbs

Use verbs when possible rather than noun forms known as “nominalizations.”

unclear (use of nominalization):

The implementation of the plan was successful.


The plan was implemented successfully.

Avoid multiple negatives

Use affirmative forms rather than several negatives because multiple negatives are

difficult to understand.

unclear (multiple negatives, passive):

Less attention is paid to commercials that lack human interest stories than to

other kinds of commercials.


People pay more attention to commercials with human interest stories than to

other kinds of commercials.

Choose action verbs over forms of be

When possible, avoid using forms of be as the main verbs in your sentences and clauses.

This problem tends to accompany nominalization (see above). Instead of using a be verb,

focus on the actions you wish to express, and choose the appropriate verbs. In the

following example, two ideas are expressed: 1) that there is a difference between

television and newspaper news reporting, and 2) the nature of that difference. The revised

version expresses these two main ideas in the two main verbs.

Unclear (overuse of be verbs):

One difference between television news reporting and the coverage provided by

newspapers is the time factor between the actual happening of an event and the

time it takes to be reported. The problem is that instantaneous coverage is

physically impossible for newspapers.


Television news reporting differs from that of newspapers in that television,

unlike newspapers, can provide instantaneous coverage of events as they happen.

Avoid unclear pronoun references

Be sure that the pronouns you use refer clearly to a noun in the current or previous

sentence. If the pronoun refers to a noun that has been implied but not stated, you can

clarify the reference by explicitly using that noun.

Unclear (unclear pronoun reference):

With the spread of globalized capitalism, American universities increasingly

follow a corporate fiscal model, tightening budgets and hiring temporary

contract employees as teachers. This has prompted faculty and adjunct

instructors at many schools to join unions as a way of protecting job security

and benefits.


With the spread of globalized capitalism, American universities increasingly

follow a corporate fiscal model, tightening budgets and hiring temporary

contract employees as teachers. This trend has prompted faculty and adjunct

instructors at many schools to join unions as a way of protecting job security

and benefits.

Unclear (unclear pronoun reference):

Larissa worked in a national forest last summer, which may be her career



Larissa worked in a national forest last summer; forest management may be her

career choice.


This resource was written by Purdue OWL.

Last full revision by Morgan Sousa.

Last edited by Dana Lynn Driscoll on September 18th 2007 at 4:54PM

Summary: When speaking, we can pause or change the tone of our voices to indicate

emphasis. When writing, we must use punctuation to indicate these places of emphasis.

This resource should help to clarify when and how to use various marks of punctuation.

Brief Overview of Punctuation

When speaking, we can pause or change the tone of our voices to indicate emphasis.

When writing, we use punctuation to indicate these places of emphases. This handout

should help to clarify when and how to use various marks of punctuation.

Independent clause: a clause that has a subject and a verb and can stand alone; a

complete sentence

Dependent clause: a clause that has a subject and a verb but cannot stand alone; an

incomplete sentence


Use a comma to join 2 independent clauses by a comma and a coordinating conjunction

(and, but, or, for, nor, so).

Road construction can be inconvenient, but it is necessary.

The new house has a large fenced backyard, so I am sure our dog will enjoy it.

Use a comma after an introductory phrase, prepositional phrase, or dependent clause.
To get a good grade, you must complete all your assignments.

Because Dad caught the chicken pox, we canceled our vacation.

After the wedding, the guests attended the reception.

Use a comma to separate elements in a series. Although there is no set rule that requires a

comma before the last item in a series, it seems to be a general academic convention to

include it. The examples below demonstrate this trend.
On her vacation, Lisa visited Greece, Spain, and Italy.

In their speeches, many of the candidates promised to help protect the

environment, bring about world peace, and end world hunger.

Use a comma to separate nonessential elements from a sentence. More specifically, when

a sentence includes information that is not crucial to the message or intent of the

sentence, enclose it in or separate it by commas.
John’s truck, a red Chevrolet, needs new tires.

When he realized he had overslept, Matt rushed to his car and hurried to work.

Use a comma between coordinate adjectives (adjectives that are equal and reversible).
The irritable, fidgety crowd waited impatiently for the rally speeches to


The sturdy, compact suitcase made a perfect gift.

Use a comma after a transitional element (however, therefore, nonetheless, also,

otherwise, finally, instead, thus, of course, above all, for example, in other words, as a

result, on the other hand, in conclusion, in addition)
For example, the Red Sox, Yankees, and Indians are popular baseball teams.

If you really want to get a good grade this semester, however, you must

complete all assignments, attend class, and study your notes.

Use a comma with quoted words.
“Yes,” she promised. Todd replied, saying, “I will be back this afternoon.”

Use a comma in a date.
October 25, 1999

Monday, October 25, 1999

25 October 1999

Use a comma in a number.

1614 High Street

Use a comma in a personal title.
Pam Smith, MD

Mike Rose, Chief Financial Officer for Operations, reported the quarter’s


Use a comma to separate a city name from the state.
West Lafayette, Indiana

Dallas, Texas

Avoid comma splices (two independent clauses joined only by a comma). Instead,

separate the clauses with a period, with a comma followed by a coordinating conjunction,

or with a semicolon.


Use a semicolon to join 2 independent clauses when the second clause restates the first or

when the two clauses are of equal emphasis.
Road construction in Dallas has hindered travel around town; streets have

become covered with bulldozers, trucks, and cones.

Use a semicolon to join 2 independent clauses when the second clause begins with a

conjunctive adverb (however, therefore, moreover, furthermore, thus, meanwhile,

nonetheless, otherwise) or a transition (in fact, for example, that is, for instance, in

addition, in other words, on the other hand, even so).
Terrorism in the United States has become a recent concern; in fact, the

concern for America’s safety has led to an awareness of global terrorism.

Use a semicolon to join elements of a series when individual items of the series already

include commas.
Recent sites of the Olympic Games include Athens, Greece; Salt Lake City, Utah;

Sydney, Australia; Nagano, Japan.


Use a colon to join 2 independent clauses when you wish to emphasize the second clause.
Road construction in Dallas has hindered travel around town: parts of Main,

Fifth, and West Street are closed during the construction.

Use a colon after an independent clause when it is followed by a list, a quotation,

appositive, or other idea directly related to the independent clause.
Julie went to the store for some groceries: milk, bread, coffee, and cheese.

In his Gettysburg Address, Abraham Lincoln urges Americans to rededicate

themselves to the unfinished work of the deceased soldiers: “It is for us the

living rather to be dedicated here to the unfinished work which they who fought

here have thus far so nobly advanced. It is rather for us to be here dedicated

to the great task remaining before us — that from these honored dead we take

increased devotion to that cause for which they gave the last full measure of

devotion — that we here highly resolve that these dead shall not have died in

vain, that this nation under God shall have a new birth of freedom, and that

government of the people, by the people, for the people shall not perish from

the earth.”

I know the perfect job for her: a politician.

Use a colon at the end of a business letter greeting.
To Whom It May Concern:

Use a colon to separate the hour and minute(s) in a time notation.
12:00 p.m.

Use a colon to separate the chapter and verse in a Biblical reference.
Matthew 1:6


Parentheses are used to emphasize content. They place more emphasis on the enclosed

content than commas. Use parentheses to set off nonessential material, such as dates,

clarifying information, or sources, from a sentence.
Muhammed Ali (1942-present), arguably the greatest athlete of all time, claimed

he would “float like a butterfly, sting like a bee.”


Dashes are used to set off or emphasize the content enclosed within dashes or the content

that follows a dash. Dashes place more emphasis on this content than parentheses.
Perhaps one reason why the term has been so problematic—so resistant to

definition, and yet so transitory in those definitions—is because of its

multitude of applications.

In terms of public legitimacy—that is, in terms of garnering support from state

legislators, parents, donors, and university administrators—English departments

are primarily places where advanced literacy is taught.

The U.S.S. Constitution became known as “Old Ironsides” during the War of 1812—

during which the cannonballs fired from the British H.M.S. Guerriere merely

bounced off the sides of the Constitution.

To some of you, my proposals may seem radical—even revolutionary.

Use a dash to set off an appositive phrase that already includes commas. An appositive is

a word that adds explanatory or clarifying information to the noun that precedes it.
The cousins—Tina, Todd, and Sam—arrived at the party together.

Quotation Marks

Use quotation marks to enclose direct quotations. Note that commas and periods are

placed inside the closing quotation mark, and colons and semicolons are placed outside.

The placement of question and exclamation marks depends on the situation.
He asked, “When will you be arriving?” I answered, “Sometime after 6:30.”

Use quotation marks to indicate the novel, ironic, or reserved use of a word.
History is stained with blood spilled in the name of “justice.”

Use quotation marks around the titles of short poems, song titles, short stories, magazine

or newspaper articles, essays, speeches, chapter titles, short films, and episodes of

television or radio shows.
“Self-Reliance,” by Ralph Waldo Emerson

“Just Like a Woman,” by Bob Dylan

“The Smelly Car,” an episode of Seinfeld

Do not use quotation marks in indirect or block quotations.


Underlining and Italics are often used interchangeably. Before word-processing programs

were widely available, writers would underline certain words to indicate to publishers to

italicize whatever was underlined. Although the general trend has been moving toward

italicizing instead of underlining, you should remain consistent with your choice

throughout your paper. To be safe, you could check with your teacher to find out which

he/she prefers. Italicize the titles of magazines, books, newspapers, academic journals,

films, television shows, long poems, plays of three or more acts, operas, musical albums,

works of art, websites, and individual trains, planes, or ships.

Romeo and Juliet by William Shakespeare

The Metamorphosis of Narcissus by Salvador Dali



Italicize foreign words.
Semper fi, the motto of the U.S. Marine Corps, means “always faithful.”

Italicize a word or phrase to add emphasis.
The truth is of utmost concern!

Italicize a word when referring to that word.
The word justice is often misunderstood and therefore misused.

Punctuation in Types of Sentences

Learning rules for how and when to punctuate a sentence can be difficult, especially

when you consider that different types of sentences call for different types of punctuation.

This handout should help to clarify not only the types of sentences, but also what

punctuation to use in what situation.

Punctuation in Types of Sentences

Independent clause: a clause that has a subject and a verb and can stand alone; a

complete sentence

Dependent clause: a clause that has a subject and a verb but cannot stand alone; an

incomplete sentence

Simple: composed of 1 independent clause.

No standard punctuation.

Compound: composed of 2 or more independent clauses.

Join 2 independent clauses by a comma and a coordinating conjunction (and, but, or, for,

nor, so).

Road construction can be inconvenient, but it is necessary.

Join 2 independent clauses by a colon when you wish to emphasize the second clause.

Road construction in Dallas has hindered travel around town: parts of Main,

Fifth, and West Street are closed during the construction.

Join 2 independent clauses by a semicolon when the second clause restates the first or

when the two clauses are of equal emphasis.

Road construction in Dallas has hindered travel around town; streets have

become covered with bulldozers, trucks, and cones.

Complex: composed of 1 or more dependent clauses and 1 or more

independent clauses.

Join an introductory dependent clause with the independent clause by a comma.

Because road construction has hindered travel around town, many people have

opted to ride bicycles or walk to work.

Many people have opted to ride bicycles or walk to work because road

construction has hindered travel around town.

Compound-Complex: composed of 1 or more dependent clauses and 2

or more independent clauses.

Join an introductory dependent clause with an independent clause with a comma.

Separate 2 independent clauses with a comma and a coordinating conjunction (and, but,

or, for, nor, so).

When it is filtered, water is cleaner, and it tastes better.

Join an introductory dependent clause with an independent clause with a comma.

Separate 2 independent clauses by a colon when you wish to emphasize the second


Whenever it is possible, you should filter your water: filtered water is

cleaner and tastes better.

Join an introductory dependent clause with an independent clause with a comma.

Separate 2 independent clauses by a semicolon when the second clause restates the first

or when the two clauses are of equal emphasis.

When it is filtered, water is cleaner and tastes better; all things considered,

it is better for you.

The distribution of police use of force across patrol
and specialty units: a case study in BWC impact

Janne E. Gaub1 & Natalie Todak2 & Michael D. White3

# Springer Nature B.V. 2020


Objectives To examine differences in use of force by police patrol and specialized
units, and the impact of body-worn cameras (BWCs) on use of force in these groups.
Methods We use administrative data from the Tempe (AZ) Police Department collect-
ed during a randomized controlled trial (RCT) of BWCs. t tests of means and ARIMA
models were constructed to analyze unit-level variation in use of force.
Results Tempe officers in specialized units use substantially more force than patrol
officers. BWCs had no impact on use of force among patrol officers but were
associated with a significant decline in force among specialty unit officers who received
BWCs in the second phase of the study.
Conclusion Unit-level variations in force can have implications for selection, training,
and other areas of police practice. Additionally, our findings show the necessity of
accounting for group variation within departments when assessing the impact of BWCs
on outcomes like use of force.

Keywords Body-worn cameras (BWCs) . Police . Use of force . Randomized controlled
trial (RCT) . Specialty units

There is a long history of racial injustice in American policing, with use of force at the
core (White and Fradella 2016). In 1968, the National Advisory Commission on Civil
Disorders concluded that “deep hostility between police and ghetto communities” was
a primary cause of the riots that occurred during that decade (The National Advisory


* Janne E. Gaub
[email protected]

1 Department of Criminal Justice and Criminology, University of North Carolina at Charlotte, 9201
University City Blvd., Charlotte, NC 28223, USA

2 Department of Criminal Justice, University of Alabama at Birmingham, Birmingham, AL, USA
3 School of Criminology and Criminal Justice, Arizona State University, Phoenix, AZ, USA

Published online: 28 May 2020

Journal of Experimental Criminology (2021) 17:545–561

Commission on Civil Disorders 1968, p. 157). Race riots sparked by police use of force
also occurred in 1980 (Miami), 1992 (Los Angeles), 1996 (St. Petersburg), and 2001

A series of more recent incidents has again demonstrated the powerful conse-
quences of police use of force against minority citizens. On August 9, 2014,
officer Darren Wilson shot and killed Michael Brown in Ferguson, Missouri.
Riots occurred the day of the shooting and again in November 2014 when the
grand jury announced its decision to not indict Wilson. Five months later, rioting
occurred in Baltimore following the death of Freddie Gray. Public protests and
demands for police reform following police killings of Brown, Gray, and other
minority citizens—including Eric Garner, Walter Scott, Samuel Dubose, and
Tamir Rice—contributed to then President Obama creating the President’s Task
Force on twenty-first Century Policing, the first presidential commission to ex-
amine police use of force in more than 40 years.

Given its devastating consequences, researchers have devoted significant atten-
tion to understanding police use of force decision-making, and over the last six
decades, a robust body of literature on the causes and correlates of the phenomena
has developed (Bittner 1970; Fyfe 1988; Shjarback and White 2016; Terrill and
Mastrofski 2002). Scholars have identified three sets of variables—situational,
social, and organizational factors—that significantly influence officer use of force
(White and Klinger 2012). However, there are still notable gaps in our under-
standing of use of force (Klinger 2008; White 2016). In particular, research is
limited as to whether force rates vary across officer working groups. Many
departments have become highly specialized, with units assigned to handle spe-
cific problems or people, such as traffic, SWAT, and anti-crime. The majority of
US police departments have specialized units (Reaves 2015), and given the
distinctive missions of some specialized units, it is reasonable to hypothesize that
officers in those assignments would be more likely to use force than officers
assigned to patrol (Gaub et al. 2020). Only two studies have examined this
question empirically, and the results are far from definitive (Brandl et al. 2001;
Williams and Westall 2003). As a result, the degree to which the nature and
prevalence of use of force may vary among patrol and specialized units remains an
open question.

Relatedly, police body-worn cameras (BWCs) have emerged as a tool to
potentially alleviate the crisis surrounding police use of force (White 2014).
Nearly 20 studies have examined the impact of BWCs on use of force by police,
and the findings are mixed (White et al. 2019). Some have documented large
declines in use of force following BWC deployment (Ariel et al. 2015; Jennings
et al. 2015), while others have reported no impact (Yokum et al. 2017). Much like
the larger literature on use of force, BWC researchers have failed to examine force
rates at the unit level. Rather, studies have calculated broad trends in use of force
across departments. In effect, the mixed findings on BWC impact may, at least
partially, be explained by the differential response to BWCs among officers in
specialty and patrol units. The current study takes a step toward addressing these
gaps in both areas of research by (1) looking more deeply at force rates across
specialty and patrol units in the Tempe (AZ) Police Department; and (2) assessing
the impact of BWCs on use of force among officers assigned to those units.

546 J. E. Gaub et al.

Literature review

Police use of force

Although the authority to use force is a defining feature of police work (Bittner 1970;
Klockars 1996), its actual use is statistically rare: There were 53.5 million police-citizen
contacts in the United States in 2015, and force was threatened or used in only 2% of
those encounters, totaling about 2900 uses of force per day (Davis et al. 2018). The
legal standard for evaluating police use of force, including deadly force, comes from
the United States Supreme Court’s ruling in Graham v. Connor (1989), which defines
appropriate force as that which a reasonable officer would have perceived as necessary,
in the moment, given the totality of the circumstances. This acknowledges the potential
for harm inherent in policing and the split-second decision-making that can affect
officer perceptions. However, the standard has been criticized for allowing too much
subjectivity in evaluating use of force (Alpert and Smith 1994; Terrill 2016) and for
failing to provide mechanisms to ensure officers do not use unnecessary or excessive
force (Mears et al. 2017; White 2016). Use of force by police and the Graham standard
have come under scrutiny amidst a backdrop of concerns about race- and class-based
disparities, tensions following high-profile police shootings, and a perceived lack of
accountability for abuse of police authority. These events have led to call for a reform
of police training and management, with a focus on use of force (e.g., President’s Task
Force on Twenty-First Century Policing 2015).

Efforts to study police use of force have been complicated by several factors,
including variations in use of force guidelines (Terrill and Paoline 2012), inconsistency
in conceptualization of key measures (Garner et al. 2002; Klahm et al. 2014), and the
availability and quality of the data (White 2016). As such, this research has generally
produced mixed results (Nix et al. 2017). Still, it is clear that an exceedingly small
portion of police-citizen contacts devolve into violence, and force that is used is most
often low in severity (Adams 1999; Bayley and Garofalo 1989; Friedrich 1980; Fyfe
2002; Garner and Maxwell 2002; Hickman et al. 2008; Reiss 1971; Worden 1995).

Correlates of police use of force

Numerous studies have examined officer- and suspect-level predictors of force. Re-
searchers have consistently reported that the majority of suspects who are shot at by the
police presented an imminent danger to the officer at the time of the shooting (Fyfe
1980, 1981; Klinger 2004). Similarly, research shows that suspect resistance is the best
predictor of less-lethal force (Mulvey and White 2014; Terrill and Mastrofski 2002).
Studies also show that more educated and experienced officers use less force (Garner
and Maxwell 2002; International Association of Chiefs of Police 2002; McElvain and
Kposowa 2008; Paoline and Terrill 2007; Schuck and Rabe-Hemp 2007). One recent
study found that military veterans in the Dallas Police Department were more likely to
be involved in a shooting, with combat-experienced veterans almost three times more
likely (Reingle Gonzalez et al. 2019). Beyond these variables, few officer-level pre-
dictors have shown consistent relationships with officer force behaviors. Some studies
have found women use less force (Brandl et al. 2001; Garner et al. 1995) while others
have found no differences (Lersch 1998; Paoline and Terrill 2004; Terrill and

547The distribution of police use of force across patrol and specialty…

Mastrofski 2002), and officer race has not been found to affect use of force (Friedrich
1980; Terrill and Mastrofski 2002).

Scholars have also focused on organizational and ecological correlates of use of
force (Friedrich 1980; Sun and Payne 2004). Environmentally, community char-
acteristics such as racial composition, arrest rates, economic inequality, and
various measures of public violence have been tied to police use of force rates.
Levels of community violence, in particular, are often positively related to rates of
police use of force (Kania and Mackey 1977; Liska and Yu 1992; Matulia 1985;
Terrill and Reisig 2003). Organizationally, informal organizational culture (Terrill
et al. 2003) and administrative policy (Fyfe 1979; Geller and Scott 1992) are
perhaps the most important factors guiding and controlling police use of force,
whereas vague or unenforced policies can lead to higher rates of deadly force
(White 2001). Shjarback and White (2016) also found a link between departmental
commitment to education (e.g., college credit requirements for applicants) and
lower rates of police-citizen violence.

Police use of force and specialized units

Specialty units were implemented in American policing during the early twentieth
century as part of a larger movement to professionalize the police through bureaucratic
principles (White 2007). In order to increase the efficiency of police to address crime,
agencies specially trained officers to focus on specific problems, such as vagrancy or
gang violence. While officers assigned to general patrol tend to handle an array of non-
criminal activities where the likelihood of using force is greatly reduced (Banton 1964;
Bittner 1967; Manning 1978; Mastrofski 1983), characteristics of specialty units may
increase the likelihood that these officers use force against citizens (Gaub et al. 2020).
For example, many specialty units are designated to respond only to high-risk calls for
service, or to target violent places and people. Others are encouraged to make a large
volume of arrests. Each of these factors may generate the use of aggressive enforcement
tactics by officers, and greater resistance from suspects (see, e.g., Hickman et al. 2008).
Additionally, Skolnick and Fyfe (1993) linked specialized units with a greater risk for
extra-legal force because of competition among units, less supervision, and the poten-
tial for the emergence of a strong subculture.

With few exceptions, the research on police use of force has focused on either
department-level trends or rates of force among patrol officers; only four studies have
systematically examined the use of force by specialty units. Campbell et al. (1998) and
Hickey and Hoffman (2003) studied dog bites in K9 units within single agencies,
finding 35–45% and 14% (respectively) of suspect apprehensions resulted in a bite.
Williams and Westall (2003) hypothesized that SWAT-certified patrol officers would
use more force during non-SWAT calls for service than general patrol officers, but the
authors found no difference between the two groups. Brandl and colleagues (Brandl
et al. 2001) studied officer assignment specialization more broadly and found no effect
on citizen complaints of excessive force. All four studies have limitations for drawing
conclusions about differential force rates among units: The first three focus on one
specialty unit, and the last examines allegations of excessive force, not actual behav-
iors. Additionally, only two (Brandl et al. 2001; Williams and Westall 2003) compared
specialty units with patrol.

548 J. E. Gaub et al.

Police body-worn cameras and use of force

BWCs have diffused rapidly in American policing, in large part because of the potential for
cameras to reduce officers’ use of force. Nineteen studies have tested the effects of BWCs on
police use of force, and roughly half (11) documented substantial or statistically significant
declines following camera deployment (White et al. 2019). The Rialto (CA) Police Depart-
ment reported a substantial decrease in use of force following the adoption of BWCs, and that
decline persisted for several years (Ariel et al. 2015; Sutherland et al. 2017). Other studies also
reported significant declines in use of force post-BWC implementation (e.g., Braga et al.
2018b; Henstock and Ariel 2017; Jennings et al. 2017; Jennings et al. 2015; White et al.
2018a). The other half, however, found no significant change in officer use of force following
BWC implementation (Ariel 2017; Ariel et al. 2015; Braga et al. 2018a; Edmonton Police
Service 2015; Headley et al. 2017; Henstock and Ariel 2017; Yokum et al. 2017). In
particular, when findings from a study with the Washington (DC) Metropolitan Police
Department were released (Yokum et al. 2017), many questioned whether the “BWC hype”
was unfounded (Ripley and Williams 2017). These mixed findings led Lum and colleagues
(2019) to conclude that “it may be fair to say…that BWCs have not produced dramatic
changes in police behavior, for better or worse […and] perhaps anticipated effects from
BWCs have been overestimated” (pp. 19–20).

Several factors could account for these mixed findings, including the degree of discretion
afforded to officers in BWC activation (Ariel et al. 2016), aspects of BWC implementation
(White et al. 2018b), and the state of the department pre-BWC deployment (Malm 2019;
White 2019). It is also possible the effect of BWCs could vary across work groups within an
agency. Much like the body of research on use of force generally, no BWC study has
examined group-level differences in use of force within an agency. It could be that BWCs
lead to decreases (or increases) in use of force among some groups but not others. These
group-level differences would be masked by agency-level analyses. Given the high costs
associated with deploying BWCs (White 2014) and more general concerns about the use of
force and its consequences, it is important for researchers to delve more deeply into the
dynamics between use of force, BWC deployment, and officer work groups. Thus, these
mixed findings suggest that a more nuanced investigation into the impact of BWCs on use of
force is warranted, which is the focus of the current study.

Data and methods

Research setting

The current analysis is part of a larger 6-month randomized controlled trial (RCT)
evaluation of BWC implementation in the Tempe (AZ) Police Department.1 Officers in
the patrol division (composed of both patrol and several specialty units [bicycle, K9,

1 The larger evaluation encompassed a number of other components (see Gaub et al. 2016, 2020; White et al.
2018b; Todak et al. 2018). The randomization protocol called for all officers below the rank of lieutenant
(including sergeants, officers, and some designated as detectives) who were assigned to the patrol division
(N = 200) to be randomly assigned to receive a BWC during either phase 1 (November 2015) or phase 2
(May 2016). The department had already planned to use a phased approach to deploying BWCs, so
randomization permitted an experimental design.

549The distribution of police use of force across patrol and specialty…

tactical response,2 gang, mounted, and traffic]) were randomly assigned to either the
treatment group (phase 1, N = 101) or control group (phase 2, N = 99). Phase 1 officers
received BWCs in November 2015, and phase 2 officers received BWCs 6 months later
in May 2016; thus, the RCT period is the 6-month interval in which phase 1 (treatment)
officers had BWCs and phase 2 (control) officers did not. While BWC deployment was
randomized, specialty unit assignment was not randomized; thus, assignment to spe-
cialty or patrol unit is quasi-experimental. Of the 200 study officers, 87 were assigned
to a specialty unit for at least 1 month during the study period. In any given month,
between 48 and 64 officers were assigned to a specialty unit. On average, specialty unit
officers were assigned to any specialized unit for 31.3 of the 48 study months. It was
rare for officers to either move (a) from a specialty unit, into patrol, and then back into a
specialty unit again, or (b) from one specialty unit to another (N = 4 for each).

Tempe, Arizona, is located just southeast of downtown Phoenix and is home to
Arizona State University (ASU)’s main campus. Tempe has a population of approxi-
mately 180,000 permanent residents and is predominantly White (72%) and Latinx
(21%). The median household income in 2016 was $50,474, with about one-fifth of
residents living under the poverty line. Violent and property crimes were both well
above the national average in 2016 (504.9 and 4558.5 per 100,000 residents, respec-
tively). The police department is medium-sized, employing approximately 330 sworn
officers. The main patrol division is divided into four areas: North, South, Central, and
Traffic. The department has several specialized police units; those participating in this
study include the bike unit, K9 unit, Tactical Response Unit (TRU), gang unit, mounted
unit, and traffic unit. Due to study parameters, only specialty units considered part of
the patrol division were included in the RCT evaluation, and thus are included here.
Other specialty units, such as the Criminal Apprehension and Surveillance Team or
undercover narcotics and vice units, never received BWCs due to the nature of their job
assignment; the Criminal Investigations Bureau received theirs long after the RCT.


We collected administrative data on use of force, calls for service, and weekly
assignment rosters for a 48-month period beginning 1 year prior to the BWC RCT
(November 1, 2014) and ending October 31, 2018. We constructed monthly force rates
for each officer in the study, per 1000 calls for service ([monthly number of force
incidents/number of calls for service] × 1000). Additionally, we separated each officer’s
monthly assignment in a specialty (1) or patrol (0) unit. Using these data, we aggre-
gated force rates by unit (patrol vs. specialty), experimental group (phase 1 vs. phase 2),
and combinations therein (see Table 1).

Analytical strategy

First, we examine use of force trends during the study period by both unit type
(specialty vs. patrol) and research group (phase 1 vs. phase 2), using independent
(between-group) and dependent (within-group) t tests of means. Next, we separate each

2 The Tactical Response Unit (TRU) is the full-time SWAT unit; several officers in other assignments are
SWAT-certified and respond to calls with TRU when a larger response is needed.

550 J. E. Gaub et al.

unit type by research group, permitting comparison among the four officer groups:
phase 1 specialty unit, phase 2 specialty unit, phase 1 patrol, and phase 2 patrol. Rates
are compared using six-month periods to be consistent with the six-month RCT period.
Finally, we conducted autoregressive integrated moving average (ARIMA) analyses to
ascertain whether use of force rates across any of those four officer groups changed
significantly following BWC deployment. ARIMA is a quasi-experimental design that
allows for comparison of pre-intervention and post-intervention (i.e., pre- and post-
BWC deployment) values of an outcome, in this case, use of force. In this study, the
technique determines whether the trend in use of force changes following BWC
deployment. ARIMA overcomes several threats to internal validity and violations of
the independence assumption (e.g., serial correlation; McDowall and McCleary 2014;
McDowall et al. 1980).


Unit and research group assignment

Figure 1 displays the monthly force rates among officers assigned to specialty and
patrol units, standardized by call activity. Officers assigned to specialty units consis-
tently use force more frequently than officers assigned to patrol. The first two columns
of Table 1 show average force rates for each officer work group, broken down into 6-
month intervals. Specifically, force rates for officers in specialty units range from a low
of 1.81 to a high of 4.33 times the rates for patrol unit officers. There are no statistically
significant within-group differences, but between-group differences (specialty com-
pared with patrol) are significant at every time-block (p < 0.05). Intuitively, this is
logical, since specialty unit officers are summoned to more contentious and potentially

Table 1 Rates of Force (per 1000 calls for service) by Research Group and Unit

Time Frame Unit Type Research Group Specialty Unit Patrol Aggregate


Patrol Phase 1 Phase 2 Phase 1 Phase 2 Phase 1 Phase 2 Rate

11/14–4/15 7.20 1.66** 2.88 2.73 7.27 7.32 1.36 1.93 2.81

5/15–10/15 5.47 2.26** 2.90 3.08 4.79 6.28 2.08 2.40 2.99

11/15–4/16† 6.96 2.23** 3.16 3.72 5.96 8.85** 1.85 2.57 3.42

5/16–10/16+ 6.20 2.59** 3.27 3.90 4.90 8.89** 2.49 2.69 3.56

11/16–4/17 6.54 2.78** 3.85 3.89 5.65 7.54** 2.81 2.64 3.86

5/17–10/17 5.60 2.19** 2.92 3.33 4.78 6.93** 2.16 2.21 3.12

11/17–4/18 6.16 2.51** 3.12 3.97 6.07 7.20 1.88 3.07 3.54

5/18–10/18 4.53 2.49** 2.96 3.03 4.95 3.84* 2.11 2.80 3.00

* Significant within-group difference (p < 0.05)
** Significant between-group difference (p < 0.05)
† Beginning of phase 1
+ Beginning of phase 2

551The distribution of police use of force across patrol and specialty…

violent calls than patrol officers (Gaub et al. 2020). However, the only studies to
empirically test this assertion failed to find statistically significant differences in use of
force between patrol and specialty unit officers (Brandl et al. 2001; Williams and
Westall 2003). Our study contradicts these findings.

The third and fourth columns of Table 1 show the standardized rates of force for all
200 study officers separated by BWC research group assignment. Using t tests of
means, we find that there are no statistically significant within-group or between-group
differences. At the aggregate group level, BWCs had no impact on the rates of use of
force, a finding that is consistent with more recent studies of BWCs and use of force
(White et al. 2019).

Four-group comparison

We next tested whether the overall trends in use of force were masked by group-level
change, which is a possibility for two reasons. First, specialty unit officers comprise a
relatively small group: Only 48–64 officers per month are members of a specialty unit
in this agency. Additionally, specialty units are called to incidents that typically receive
greater scrutiny; thus, these officers may respond differently to being filmed compared
with those working general patrol. To test this hypothesis, we separate officers by both
research group assignment and unit assignment (see remaining columns in Table 1) and
compared rates among the groups over time.

Notably, phase 1 specialty unit officers used significantly less force than phase 2
specialty unit officers for the first 2 years after BWCs were deployed to phase 1 officers
(November 2015–October 2017), with no corresponding difference in patrol. This
difference diminished for the last year of the study period (November 2017–October
2018). Additional analysis showed that no single specialty unit was driving this finding
in terms of number of phase 1 or 2 officers; in other words, no single unit has far fewer
phase 1 officers, or far more phase 2 officers, compared with others. This eliminates the
possibility that the proportion of phase 1 and 2 officers in any specific specialty unit
was driving this finding. There are, however, several alternative explanations for this
finding. For example, the finding could be driven by specific officers, opportunity to
engage in force, or a combination thereof. Officers in specialty units have, by virtue of


























































11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10

Monthly Rates of Force, by Unit Type

Patrol Specialty

Fig. 1 Rates of Force (per 1000 calls for service) by Unit Type

552 J. E. Gaub et al.

their mission and assignment, greater opportunity to engage in use of force. As such,
when they are moved back into patrol, the opportunity or inclination to respond with
force is removed or mitigated. In short, there are noteworthy but perplexing group
differences within specialty units as a whole.

Time series analysis

We identified the best-fitting model for all phase 1 officers (2,1,0) and all phase 2
officers (0,1,1), as well as each subgroup: phase 1 patrol (2,1,0), phase 1 specialty
(1,0,1), phase 2 patrol (0,1,1), and phase 2 specialty (0,1,1) (see Table 2). We then
conducted interrupted time series analysis with each officer group, testing BWC impact
with varying onsets (abrupt, gradual) and duration (temporary, permanent), starting in
November 2015 for phase 1 officer groups and May 2016 for phase 2 officer groups.
There was only one statistically significant finding: a gradual, permanent decline in use
of force among phase 2 specialty officers starting in February 2017 (9-month delayed
onset after BWC deployment) and persisting through the end of the study period (see
also Fig. 2). The introduction of BWCs was not associated with change in force rates
for any other officer group.


While there is a robust literature analyzing correlates of police coercive behavior and a
growing body of research on BWCs, scholars in both fields have traveled the same path
and left the same question unanswered: are there unit-level differences in use of force?
Our study bridges this gap in both areas of research, and we have two primary findings.

First, use of force rates for officers assigned to specialty units were nearly four times
greater than those of officers assigned to general patrol units, and this finding was
statistically significant over the entire study period. We account for unit-level variation
in call activity and unit assignment changes. Still, Tempe officers in specialty units use
force far more frequently than officers in patrol units. To our knowledge, this is the first
study to identify such disparate rates of force among officer work groups. Second, we

Table 2 Results from ARIMA Across Officer Groups

Officer groups Model Abrupt



Phase 1 (2,1,0) X X X

Phase 2 (0,1,1) X X X

Phase 1 only

Patrol (2,1,0) X X X

Specialty (1,0,1) X X X

Phase 2 only

Patrol (0,1,1) X X X

Specialty (0,1,1) X − 0.204 (0.101)* 2/17 X

* p < 0.05

553The distribution of police use of force across patrol and specialty…

find that the implementation of BWCs had no impact on use of force at the department
level. This is true cross-sectionally, looking at each time-block using t tests of means,
and longitudinally using ARIMA, though we see a slightly different story at the unit

Given the serious implications of police use of force, it is critical that we have a
thorough understanding of not only department-level trends, but also the prevalence
and distribution of force within a department. Only two studies have addressed use of
force in specialized police units: One focused on one specialty unit (SWAT; Williams
and Westall 2003) and the other examined citizen complaints of excessive force rather
than actual use of force behaviors (Brandl et al. 2001). By comparison, our study is a
rigorous assessment of all officer use of force over a 4-year period comparing multiple
specialty units with general patrol, and we find that officers in specialty units consis-
tently use force at a higher rate than patrol officers. This suggests that significantly
more attention should be paid to the behaviors of police specialty units. Given the
current focus placed on police use of force and public unrest concerning its perceived
excessive use against minorities, the dearth of research addressing coercive behaviors
used by the specialty units who respond to high-risk calls for service is …

Paragraphs & Paragraphing

This resource was written by Purdue OWL.

Last full revision by Dana Lynn Driscoll.

Last edited by Dana Lynn Driscoll on August 16th 2006 at 3:04PM

Summary: The purpose of this handout is to give some basic instruction and advice

regarding the creation of understandable and coherent paragraphs.

On Paragraphs

What is a paragraph?

A paragraph is a collection of related sentences dealing with a single topic. Learning to

write good paragraphs will help you as a writer stay on track during your drafting and

revision stages. Good paragraphing also greatly assists your readers in following a piece

of writing. You can have fantastic ideas, but if those ideas aren’t presented in an

organized fashion, you will lose your readers (and fail to achieve your goals in writing).

The Basic Rule: Keep One Idea to One Paragraph

The basic rule of thumb with paragraphing is to keep one idea to one paragraph. If you

begin to transition into a new idea, it belongs in a new paragraph. There are some simple

ways to tell if you are on the same topic or a new one. You can have one idea and several

bits of supporting evidence within a single paragraph. You can also have several points in

a single paragraph as long as they relate to the overall topic of the paragraph. If the single

points start to get long, then perhaps elaborating on each of them and placing them in

their own paragraphs is the route to go.

Elements of a Paragraph

To be as effective as possible, a paragraph should contain each of the following: Unity,

Coherence, A Topic Sentence, and Adequate Development. As you will see, all of

these traits overlap. Using and adapting them to your individual purposes will help you

construct effective paragraphs.


The entire paragraph should concern itself with a single focus. If it begins with a one

focus or major point of discussion, it should not end with another or wander within

different ideas.


Coherence is the trait that makes the paragraph easily understandable to a reader. You

can help create coherence in your paragraphs by creating logical bridges and verbal


Logical bridges

 The same idea of a topic is carried over from sentence to sentence

 Successive sentences can be constructed in parallel form

Verbal bridges

 Key words can be repeated in several sentences

 Synonymous words can be repeated in several sentences

 Pronouns can refer to nouns in previous sentences

 Transition words can be used to link ideas from different sentences

A topic sentence

A topic sentence is a sentence that indicates in a general way what idea or thesis the

paragraph is going to deal with. Although not all paragraphs have clear-cut topic

sentences, and despite the fact that topic sentences can occur anywhere in the paragraph

(as the first sentence, the last sentence, or somewhere in the middle), an easy way to

make sure your reader understands the topic of the paragraph is to put your topic sentence

near the beginning of the paragraph. (This is a good general rule for less experienced

writers, although it is not the only way to do it). Regardless of whether you include an

explicit topic sentence or not, you should be able to easily summarize what the paragraph

is about.

Adequate development

The topic (which is introduced by the topic sentence) should be discussed fully and

adequately. Again, this varies from paragraph to paragraph, depending on the author’s

purpose, but writers should beware of paragraphs that only have two or three sentences.

It’s a pretty good bet that the paragraph is not fully developed if it is that short.

Some methods to make sure your paragraph is well-developed:

 Use examples and illustrations

 Cite data (facts, statistics, evidence, details, and others)

 Examine testimony (what other people say such as quotes and paraphrases)

 Use an anecdote or story

 Define terms in the paragraph

 Compare and contrast

 Evaluate causes and reasons

 Examine effects and consequences

 Analyze the topic

 Describe the topic

 Offer a chronology of an event (time segments)

How do I know when to start a new paragraph?

You should start a new paragraph when:

 When you begin a new idea or point. New ideas should always start in new

paragraphs. If you have an extended idea that spans multiple paragraphs, each

new point within that idea should have its own paragraph.

 To contrast information or ideas. Separate paragraphs can serve to contrast

sides in a debate, different points in an argument, or any other difference.

 When your readers need a pause. Breaks in paragraphs function as a short

“break” for your readers—adding these in will help your writing more readable.

You would create a break if the paragraph becomes too long or the material is


 When you are ending your introduction or starting your conclusion. Your

introductory and concluding material should always be in a new paragraph. Many

introductions and conclusions have multiple paragraphs depending on their

content, length, and the writer’s purpose.

Transitions and Signposts

Two very important elements of paragraphing are signposts and transitions. Signposts are

internal aids to assist readers; they usually consist of several sentences or a paragraph

outlining what the article has covered and where the article will be going.

Transitions are usually one or several sentences that “transition” from one idea to the

next. Transitions can be used at the end of most paragraphs to help the paragraphs flow

one into the next.

How to Write a Literature Review

1. Introduction

Not to be confused with a book review, a literature review surveys scholarly articles, books and other

sources (e.g. dissertations, conference proceedings) relevant to a particular issue, area of research, or

theory, providing a description, summary, and critical evaluation of each work. The purpose is to offer an

overview of significant literature published on a topic.

2. Components

Similar to primary research, development of the literature review requires four stages:

 Problem formulation—which topic or field is being examined and what are its component issues?

 Literature search—finding materials relevant to the subject being explored

 Data evaluation—determining which literature makes a significant contribution to the understanding

of the topic

 Analysis and interpretation—discussing the findings and conclusions of pertinent literature

Literature reviews should comprise the following elements:

 An overview of the subject, issue or theory under consideration, along with the objectives of the

literature review

 Division of works under review into categories (e.g. those in support of a particular position, those

against, and those offering alternative theses entirely)

 Explanation of how each work is similar to and how it varies from the others

 Conclusions as to which pieces are best considered in their argument, are most convincing of their

opinions, and make the greatest contribution to the understanding and development of their area of


In assessing each piece, consideration should be given to:

 Provenance—What are the author’s credentials? Are the author’s arguments supported by

evidence (e.g. primary historical material, case studies, narratives, statistics, recent scientific


 Objectivity—Is the author’s perspective even-handed or prejudicial? Is contrary data considered or

is certain pertinent information ignored to prove the author’s point?

 Persuasiveness—Which of the author’s theses are most/least convincing?

 Value—Are the author’s arguments and conclusions convincing? Does the work ultimately

contribute in any significant way to an understanding of the subject?

3. Definition and Use/Purpose

A literature review may constitute an essential chapter of a thesis or dissertation, or may be a self-contained

review of writings on a subject. In either case, its purpose is to:

 Place each work in the context of its contribution to the understanding of the subject under review

 Describe the relationship of each work to the others under consideration

 Identify new ways to interpret, and shed light on any gaps in, previous research

 Resolve conflicts amongst seemingly contradictory previous studies

 Identify areas of prior scholarship to prevent duplication of effort

 Point the way forward for further research

 Place one’s original work (in the case of theses or dissertations) in the context of existing literature

The literature review itself, however, does not present new primary scholarship.

Creating a Thesis Statement

This resource was written by Erin Karper.

Last full revision by Elyssa Tardiff.

Last edited by Karl Stolley on September 28th 2006 at 2:44PM

Summary: This resource provides tips for creating a thesis statement and examples of

different types of thesis statements.

Tips and Examples for Writing Thesis Statements

Tips for Writing Your Thesis Statement

1.Determine what kind of paper you are writing:

 An analytical paper breaks down an issue or an idea into its component parts,

evaluates the issue or idea, and presents this breakdown and evaluation to the


 An expository (explanatory) paper explains something to the audience.

 An argumentative paper makes a claim about a topic and justifies this claim with

specific evidence. The claim could be an opinion, a policy proposal, an

evaluation, a cause-and-effect statement, or an interpretation. The goal of the

argumentative paper is to convince the audience that the claim is true based on the

evidence provided.

If you are writing a text which does not fall under these three categories (ex. a narrative),

a thesis statement somewhere in the first paragraph could still be helpful to your reader.

2. Your thesis statement should be specific—it should cover only what you will discuss

in your paper and should be supported with specific evidence.

3. The thesis statement usually appears at the end of the first paragraph of a paper.

4. Your topic may change as you write, so you may need to revise your thesis statement

to reflect exactly what you have discussed in the paper.

Thesis Statement Examples

Example of an analytical thesis statement:

An analysis of the college admission process reveals two principal problems

facing counselors: accepting students with high test scores or students with

strong extracurricular backgrounds.

The paper that follows should:

 explain the analysis of the college admission process

 explain the two problems facing admissions counselors

Example of an expository (explanatory) thesis statement:

The life of the typical college student is characterized by time spent

studying, attending class, and socializing with peers.

The paper that follows should:

 explain how students spend their time studying, attending class, and socializing

with peers

Example of an argumentative thesis statement:

High school graduates should be required to take a year off to pursue community

service projects before entering college in order to increase their maturity

and global awareness.

The paper that follows should:

 present an argument and give evidence to support the claim that students should

pursue community projects before entering college

This resource was written by Purdue OWL.

Appropriate Language: Overview

When writing, it is very important to use language that fits your the audience you are writing for and

the purpose you want to achieve. Inappropriate language uses can damage your credibility,

undermine your argument, or alienate your audience. This handout will cover some of the major

issues with appropriate language use: levels of language formality, deceitful language and

Euphemisms, slang and idiomatic expressions; using group-specific jargon; and biased/stereotypical


The following is a short overview of the different aspects of using appropriate language. Review the

other sections of this handout for a more complete discussion.

1. Levels of Formality: Write in a style that your audience expects and that fits your

purpose is key to successful writing.

2. In-Group Jargon: Jargon refers to specialized language used by groups of like-minded

individuals. Only use in-group jargon when you are writing for members of that group.

You should never use jargon for a general audience without first explaining it.

3. Slang and idiomatic expressions: Avoid using slang or idiomatic expressions in

general academic writing.

4. Deceitful language and Euphemisms: Avoid using euphemisms (words that veil the

truth, such as “collateral damage” for the unintended destruction of civilians and their

property) and other deceitful language.

5. Biased language: Avoid using any biased language including language with a racial,

ethnic, group, or gender bias or language that is stereotypical.

6. Levels of Formality
7. The level of formality you write with should be

determined by the expectations of your audience

and your purpose. For example, if you are writing

a cover letter for a job application or a college

academic essay, you would write in a formal style.

If you are writing a letter to a friend, writing

something personal, or even writing something

for a humorous or special interest magazine when

informal writing is expected, you would use a

more informal style. Formality exists on a scale—

in the example below, a letter of application to a

known colleague can result in a semi-formal style.

8. Here is an example:

9. Formal (Written to an unknown audience): I

am applying for the receptionist position

advertised in the local paper. I am an

excellent candidate for the job because of

my significant secretarial experience,

good language skills, and sense of


10. Semi-formal (Written to a well-known

individual): I am applying for the

receptionist position that is currently

open in the company. As you are aware, I

have worked as a temporary employee with

your company in this position before. As

such, I not only have experience and

knowledge of this position, but also

already understand the company’s needs and

requirements for this job.

11. Informal (Incorrect): Hi! I read in the

paper that ya’ll were looking for a

receptionist. I think that I am good for

that job because I’ve done stuff like it

in the past, am good with words, and am

incredibly well organized.

Group Jargon

The term “jargon” refers to any in-group or specialized language used by small groups of like-minded

individuals. This terminology is usually specialized to the function of the group, and will be used by

and among group members as a sign of belonging, status, and for keeping out outsiders.

For example, individuals who study linguistics will use words like quantifier, voiceless labiodental

fricative, diglossia, intensifier, minimal pair and metonymy. To non-linguists, these words have

different meanings or no meanings at all.

When making the choice of what vocabulary to use, you should first and foremost consider the

audience that you are addressing:

If you are writing for a general audience (even an general academic audience) you should avoid using

in-group jargon without explanations. Overloading your audience with words they do not understand

will not help you achieve your purpose.

For example, if you are writing a paper explaining concepts in linguistics to an

audience of non-linguists, you might introduce and explain a few important terms. But

you wouldn’t use those terms without an explanation or in a way your audience wouldn’t


If, however, you are writing to an in-group audience you will want to use group-specific jargon. Not

using the jargon when it is expected by your audience can signal to the audience that you are not a

member of that group or have not mastered the group’s terminology. This will most likely damage

your credibility and interfere with your purpose in writing.

For example, if you are writing a conference paper for a group of linguists or a term

paper for a college-level linguistics course, you should use in-group jargon to help

show that you understand the concepts and can discuss them in ways other linguists


Slang and Idiomatic Expressions

You should avoid using slang (words like ya’ll, yinz, cool) or idiomatic expressions (“pull someone’s

leg”, “spill the beans”, and “something smells fishy”) in formal academic writing. These words make

your writing sound informal, and hence, less credible. Furthermore, for non-native speakers of

English, these expressions may prove more difficult to understand because of their non-literal nature.

Times do exist, however, when the use of slang and idiomatic expressions are appripriate. Think about

who your audience is, what they expect, and how the use of these words may help or hinder your

purpose. If you are writing a very informal or humorous piece, slang or idiomatic expressions may be


Deceitful Language and Euphemisms

Deceitful Language and Euphemisms

You should avoid using any language whose purpose is deceitful. Euphemisms are terms that attempt

to cover up that which is wrong, unethical, taboo, or harsh.

Here are some examples from the military:

 Pacification = The act of forcefully exerting outside government over a previously

autonomous people

 Friendly Fire = Being shot at (unintentionally) by your own allies

 Collateral Damage = Destruction of property and killing of innocent civilians during war


 Sunshine Units = A term for a power plant that is leaking radiation into the surrounding


Complex or Confusing Language

Language can also be deceitful if it is overly complex or confusing. Confusing language is deliberately

created complex and is used to downplay the truth or to evade responsibility. Here is an example:

The acquisition of pollution permits by individuals and corporations that produce

toxins has now been allowed by the recently amended Clean Air Act of 1990. Institution

of permits simplifies and clarifies obligations for business and industry, making

environmental protections more accessible for these constituents. The government and

the Environmental Protection Agency will be greatly assisted in their endeavors by

monitoring the release of all substances and having the substances listed on one

individual permit.

Although this paragraph makes it seem like this facet of the Clean Air act is helping the environment,

the EPA, and the federal government, in reality all it is doing is explaining the new permit system that

allows permit holders to release pollutants into the environment.

Group Terminology

Depending on your purpose, however, some terms that may be considered euphanisms may be

appropriate or even sanctioned by groups they affect. For example, it is more correct to say “persons

with disabilities” or “differently-abled persons” than to call someone “handicapped” “crippled” or even

“disabled.” In these cases, it is important to use what is considered correct by the group in question.

Stereotypes and Biased Language

Avoid using language that is stereotypical or biased in any way. Biased language frequently occurs

with gender, but can also offend groups of people based on sexual orientation, ethnicity, interest, or


Stereotyped Language

Stereotyped language is any that assumes a stereotype about a group of people. For example, don’t

assume a common stereotype about blonde women:

Incorrect: Although she was blonde, Mary was still intelligent.

Revised: Mary was intelligent.

Non-Sexist language

Writing in a non-sexist, non-biased way is both ethically sound and effective. Non-sexist writing is

necessary for most audiences; if you write in a sexist manner and alienate much of your audience

from your discussion, your writing will be much less effective.

The National Council of Teachers of English (NCTE) suggests the following guidelines:

Generic Use

Although MAN in its original sense carried the dual meaning of adult human and adult male, its

meaning has come to be so closely identified with adult male that the generic use of MAN and other

words with masculine markers should be avoided.

 Original: mankind

 Alternatives: humanity, people, human beings

 Original:man’s achievements

 Alternative: human achievements

 Original: man-made

 Alternatives: synthetic, manufactured, machine-made

 Original: the common man

 Alternatives: the average person, ordinary people

 Original: man the stockroom

 Alternative: staff the stockroom

 Original: nine man-hours

 Alternative: nine staff-hours


Avoid the use of MAN in occupational terms when persons holding the job could be either male or


 Original: chairman

 Alternatives: coordinator (of a committee or department), moderator (of a meeting),

presiding officer, head, chair

 Original: businessman

 Alternatives: business executive, business person

 Original: fireman

 Alternative: firefighter

 Original: mailman

 Alternative: mail carrier

 Original: steward and stewardess

 Alternative: flight attendant

 Original: policeman and policewoman

 Alternative: police officer

 Original: congressman

 Alternative: congressional representative

Historically, some jobs have been dominated by one gender or the other. This has lead to the

tendency for a person of the opposite gender to be “marked” by adding a reference to gender. You

should avoid marking the gender in this fashion in your writing.

 Original: male nurse

 Alternative: nurse

 Original: woman doctor

 Alternative: doctor

Appropriate Pronoun Usage

Because English has no generic singular—or common-sex—pronoun, we have used HE, HIS, and HIM

in such expressions as “the student needs HIS pencil.” When we constantly personify “the judge,” “the

critic,” “the executive,” “the author,” and so forth, as male by using the pronoun HE, we are subtly

conditioning ourselves against the idea of a female judge, critic, executive, or author. There are

several alternative approaches for ending the exclusion of women that results from the pervasive use

of masculine pronouns.

Recast into the plural

 Original: Give each student his paper as soon as he is finished.

 Alternative:Give students their papers as soon as they are finished.

Reword to eliminate gender problems.

 Original: The average student is worried about his grade.

 Alternative: The average student is worried about grades.

Replace the masculine pronoun with ONE, YOU, or (sparingly) HE OR SHE, as appropriate.

 Original: If the student was satisfied with his performance on the pretest, he took the post-


 Alternative: A student who was satisfied with her or his performance on the pretest took the


Alternate male and female examples and expressions. (Be careful not to confuse the


 Original: Let each student participate. Has he had a chance to talk? Could he feel left out?

 Alternative: Let each student participate. Has she had a chance to talk? Could he feel left


Indefinite Pronouns

Using the masculine pronouns to refer to an indefinite pronoun (everybody, everyone, anybody,

anyone) also has the effect of excluding women. In all but strictly formal uses, plural pronouns have

become acceptable substitutes for the masculine singular.

 Original: Anyone who wants to go to the game should bring his money tomorrow.

 Alternative: Anyone who wants to go to the game should bring their money tomorrow.

Avoiding Plagiarism

This resource was written by Purdue OWL.

Last full revision by Karl Stolley.

Last edited by Dana Lynn Driscoll on September 18th 2007 at 4:20PM

Summary: There are few intellectual offenses more serious than plagiarism in academic

and professional contexts. This resource offers advice on how to avoid plagiarism in your


Research-based writing in American institutions, both educational and corporate, is filled

with rules that writers, particularly beginners, aren’t aware of or don’t know how to

follow. Many of these rules have to do with research and proper citation. Gaining a

familiarity of these rules, however, is critically important, as inadvertent mistakes can

lead to charges of plagiarism, which is the uncredited use (both intentional and

unintentional) of somebody else’s words or ideas.

While some cultures may not insist so heavily on documenting sources of words, ideas,

images, sounds, etc., American culture does. A charge of plagiarism can have severe

consequences, including expulsion from a university or loss of a job, not to mention a

writer’s loss of credibility and professional standing. This resource, which does not reflect

any official university policy, is designed to help you develop strategies for knowing how

to avoid accidental plagiarism..

*(Students will want to make sure that they are familiar with University of South

Florida’s official academic dishonesty policy as well as any additional policies that their

instructors have implemented.)*

Intellectual Challenges in American Academic Writing

There are some intellectual challenges that all students are faced with when writing.

Sometimes these challenges can almost seem like contradictions, particularly when

addressing them within a single paper. For example, American teachers often instruct

students to:

 Develop a topic based on what has already been said and written but write

something new and original

 Rely on opinions of experts and authorities on a topic but improve upon and/or

disagree with those same opinions

 Give credit to researchers who have come before you but make your own

significant contribution

 Improve your English or fit into a discourse community by building upon what

you hear and read but use your own words and your own voice

Is It Plagiarism Yet?

There are some actions that can almost unquestionably be labeled plagiarism. Some of

these include buying, stealing, or borrowing a paper (including, of course, copying an

entire paper or article from the Web); hiring someone to write your paper for you; and

copying large sections of text from a source without quotation marks or proper citation.

But then there are actions that are usually in more of a gray area. Some of these include

using the words of a source too closely when paraphrasing (where quotation marks

should have been used) or building on someone’s ideas without citing their spoken or

written work. Sometimes teachers suspecting students of plagiarism will consider the

students’ intent, and whether it appeared the student was deliberately trying to make ideas

of others appear to be his or her own.

However, other teachers and administrators may not distinguish between deliberate and

accidental plagiarism. So let’s look at some strategies for avoiding even suspicion of

plagiarism in the first place

When Do We Give Credit?

The key to avoiding plagiarism is to make sure you give credit where it is due. This may

be credit for something somebody said, wrote, emailed, drew, or implied. Many

professional organizations, including the Modern Language Association and the

American Psychological Association, have lengthy guidelines for citing sources.

However, students are often so busy trying to learn the rules of MLA format and style or

APA format and style that they sometimes forget exactly what needs to be credited. Here,

then, is a brief list of what needs to be credited or documented:

 Words or ideas presented in a magazine, book, newspaper, song, TV program,

movie, Web page, computer program, letter, advertisement, or any other medium

 Information you gain through interviewing or conversing with another person,

face to face, over the phone, or in writing

 When you copy the exact words or a unique phrase

 When you reprint any diagrams, illustrations, charts, pictures, or other visual


 When you reuse or repost any electronically-available media, including images,

audio, video, or other media

Bottom line, document any words, ideas, or other productions that originate somewhere

outside of you.

There are, of course, certain things that do not need documentation or credit, including:

 Writing your own lived experiences, your own observations and insights, your

own thoughts, and your own conclusions about a subject

 When you are writing up your own results obtained through lab or field


 When you use your own artwork, digital photographs, video, audio, etc.

 When you are using “common knowledge,” things like folklore, common sense

observations, myths, urban legends, and historical events (but not historical


 When you are using generally-accepted facts, e.g., pollution is bad for the

environment, including facts that are accepted within particular discourse

communities, e.g., in the field of composition studies, “writing is a process” is a

generally-accepted fact.

Deciding if Something is “Common Knowledge”

Generally speaking, you can regard something as common knowledge if you find the

same information undocumented in at least five credible sources. Additionally, it might

be common knowledge if you think the information you’re presenting is something your

readers will already know, or something that a person could easily find in general

reference sources. But when in doubt, cite; if the citation turns out to be unnecessary,

your teacher or editor will tell you.

Safe Practices

Most students, of course, don’t intend to plagiarize. In fact, most realize that citing

sources actually builds their credibility for an audience and even helps writers to better

grasp information relevant to a topic or course of study. Mistakes in citation and crediting

can still happen, so here are certain practices that can help you not only avoid plagiarism,

but even improve the efficiency and organization of your research and writing.

Best Practices for Research and Drafting

Reading and Note-Taking

 In your notes, always mark someone else’s words with a big Q, for quote, or use

big quotation marks

 Indicate in your notes which ideas are taken from sources with a big S, and which

are your own insights (ME)

 When information comes from sources, record relevant documentation in your

notes (book and article titles; URLs on the Web)

Writing Paraphrases or Summaries

 Use a statement that credits the source somewhere in the paraphrase or summary,

e.g., According to Jonathan Kozol, ….

 If you’re having trouble summarizing, try writing your paraphrase or summary of

a text without looking at the original, relying only on your memory and notes

 Check your paraphrase or summary against the original text; correct any errors in

content accuracy, and be sure to use quotation marks to set off any exact phrases

from the original text

 Check your paraphrase or summary against sentence and paragraph structure, as

copying those is also considered plagiarism.

 Put quotation marks around any unique words or phrases that you cannot or do

not want to change, e.g., “savage inequalities” exist throughout our educational

system (Kozol).

Writing Direct Quotations

 Keep the source author’s name in the same sentence as the quote

 Mark the quote with quotation marks, or set it off from your text in its own block,

per the style guide your paper follows

 Quote no more material than is necessary; if a short phrase from a source will

suffice, don’t quote an entire paragraph

 To shorten quotes by removing extra information, use ellipsis points (…) to

indicate omitted text, keeping in mind that:

o Three ellipsis points indicates an in-sentence ellipsis, and four points for

an ellipsis between two sentences

 To give context to a quote or otherwise add wording to it, place added words in

brackets, []; be careful not to editorialize or make any additions that skew the

original meaning of the quote—do that in your main text, e.g.,

o OK: Kozol claims there are “savage inequalities” in our educational

system, which is obvious.

o WRONG: Kozol claims there are “[obvious] savage inequalities” in our

educational system.

 Use quotes that will have the most rhetorical, argumentative impact in your paper;

too many direct quotes from sources may weaken your credibility, as though you

have nothing to say yourself, and will certainly interfere with your style

Writing About Another’s Ideas

 Note the name of the idea’s originator in the sentence or throughout a paragraph

about the idea

 Use parenthetical citations, footnotes, or endnotes to refer readers to additional

sources about the idea, as necessary

 Be sure to use quotation marks around key phrases or words that the idea’s

originator used to describe the idea

Maintaining Drafts of Your Paper

Sometimes innocent, hard-working students are accused of plagiarism because a

dishonest student steals their work. This can happen in all kinds of ways, from a

roommate copying files off of your computer, to someone finding files on a disk or pen

drive left in a computer lab. Here are some practices to keep your own intellectual

property safe:

 Do not save your paper in the same file over and over again; use a numbering

system and the Save As… function. E.g., you might have research_paper001.doc,

research_paper002.doc, research_paper003.doc as you progress. Do the same

thing for any HTML files you’re writing for the Web. Having multiple draft

versions may help prove that the work is yours (assuming you are being ethical in

how you cite ideas in your work!).

 Maintain copies of your drafts in numerous media, and different secure locations

when possible; don’t just rely on your hard drive or pen drive.

 Password-protect your computer; if you have to leave a computer lab for a quick

bathroom break, hold down the Windows key and L to lock your computer

without logging out.

 Password-protect your files; this is possible in all sorts of programs, from Adobe

Acrobat to Microsoft word (just be sure not to forget the password!)

Revising, Proofreading, and Finalizing Your Paper

 Proofread and cross-check with your notes and sources to make sure that anything

coming from an outside source is acknowledged in some combination of the

following ways:

o In-text citation, otherwise known as parenthetical citation

o Footnotes or endnotes

o Bibliography, References, or Works Cited pages

o Quotation marks around short quotes; longer quotes set off by themselves,

as prescribed by a research and citation style guide

o Indirect quotations: citing a source that cites another source

 If you have any questions about citation, ask your instructor well in advance of

your paper’s due date, so if you have to make any adjustments to your citations,

you have the time to do them well

Is It a Scholarly Journal?



 Is the article divided into sections with headings such as those listed below?

o Introduction

o Theory or Background

o Methods

o Discussion

o Literature review

o Subjects

o Results

o Conclusion

 Is there an abstract (summary) at the beginning of the article?

 Is the tone of the article thoughtful, restrained and serious?

 Does the article have footnotes or citations of other sources?

 Does the article have a bibliography or list of references at the end?

 Are the author’s credentials listed?

 Is the topic of the article narrowly focused and explored in depth?

 Is the article based on either original research or authorities in the field (as opposed to

personal opinion)?

 Is the article written for readers with some prior knowledge of the subject?


 Is the journal published or sponsored by a professional scholarly society, professional

association, or university academic department?


 Did you find a citation for it in one of the electronic databases that includes scholarly

publications? (Criminal Justice Abstracts, EBSCOhost Academic Search Premier,

PsycINFO, Sociological Abstracts) Read the database description to see if scholarly

publications are included.

 Did you use the option on the database search screen to limit the results to scholarly or

peer reviewed publications?

CRIMINAL JUSTICE AND BEHAVIOR, 2021, Vol. 48, No. 6, June 2021, 734 –754.

DOI: https://doi.org/10.1177/0093854820970583

Article reuse guidelines: sagepub.com/journals-permissions

© 2020 International Association for Correctional and Forensic Psychology


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Police Department


Urban Institute

Police body-worn cameras (BwCs) can help improve transparency, accountability, and policing behaviors. This study
extends prior BwC research by using a panel analysis design with a measure of treatment duration to examine how the effects
of BwCs change over time. Using data from the Milwaukee Police Department (N = 1,009), we propose and test two com-
peting hypotheses: The program maturity hypothesis suggests that BwCs will be more effective at reducing use of force and
complaints over time, whereas the program fatigue hypothesis expects BwCs to be less effective the longer officers wear
BwCs. we find that BwCs reduced complaints overall and that, over time, each additional month with a camera resulted in
6% fewer complaints. There was no overall relationship between BwCs and use of force, but our treatment duration model
suggests that there was an immediate decrease in use of force incidents, followed by a gradual increase in subsequent months.

Keywords: body-worn cameras; BwC; police; use of force; complaints; longitudinal; panel analysis


In recent years, body-worn cameras (BwCs) have become nearly ubiquitous with polic-
ing. In the most recent survey available, nearly half of all general-purpose law enforcement

aUthors’ note: This project was supported by Grant No. 2015-WY-BX-0006 awarded by the Bureau of
Justice Assistance. The Bureau of Justice Assistance is a component of the Department of Justice’s Office of Justice
Programs, which also includes the Bureau of Justice Statistics, the National Institute of Justice, the Office of
Juvenile Justice and Delinquency Prevention, the Office for Victims of Crime, and the SMART Office. The opinions,
findings, conclusions, and recommendations expressed here are those of the authors and should not be attributed
to the U.S. Department of Justice, the Urban Institute, its trustees, or its funders. Funders do not determine research
findings or the insights and recommendations of Urban experts. Further information on the Urban Institute’s fund-
ing principles is available at urban.org/fundingprinciples. We would like to thank staff from the Milwaukee Police
Department, especially Sgt. Doug Wiorek, who played a significant role in working with the researchers for this
study and article. Correspondence concerning this article should be addressed to Bryce E. Peterson, Justice Policy
Center, Urban Institute, 500 L’Enfant Plaza SW, Washington, DC 20024; e-mail: [email protected]

970583CJBXXX10.1177/0093854820970583Criminal Justice and BehaviorPeterson, lawrence / short title


agencies in the United States had cameras, whereas 80% of departments with 500 or more
officers had a BwC program (Hyland, 2018). The top reasons for deploying these devices
were to improve officer safety, reduce complaints from community members, improve evi-
dence quality, reduce agency liability, and improve accountability (Hyland, 2018). In short,
police departments have adopted cameras to enhance the day-to-day operations of the
agency and improve transparency and accountability among their officers.

These aims and motivations have been amplified by the recent social movements in the
United States advocating for dramatic police reform following the tragic deaths of George
Floyd and Breonna Taylor, among others. In the wake of these events, several states, includ-
ing New Mexico (Senate Bill 8, 2020) and Colorado (Senate Bill 20-217, 2020), have
enacted new laws requiring the statewide use of police body cameras, while both parties in
Congress have similarly proposed police legislation that would require federal officers to
wear BwCs and provide funding for local departments to purchase cameras (Norwood,
2020). Groups like the National Association for the Advancement of Colored People
(NAACP), American Civil Liberties Union (ACLU), and public defender agencies are also
calling for police body cameras and strong policies to guide their use (Lenninger, 2020;
Miles, 2020; Stanley, 2020). These reform efforts and calls to action emphasize the poten-
tial for BwCs to hold officers accountable, make departments more transparent, and help
rebuild community trust.

As a measure of these concepts, early research linked the efficacy of BwCs to their abil-
ity to reduce use of force incidents and citizen complaints. A study in Rialto, California,
found steep reductions in both use of force and citizen complaints after the department
deployed BwCs (Ariel et al., 2015; Farrar & Ariel, 2013; see also Katz et al., 2014). In
more recent years, the impact of BwCs on these outcomes is mixed. Some authors contin-
ued to find reductions in complaints and force (Braga et al., 2017; Jennings et al., 2017)
while others only found reductions in complaints (Ariel et al., 2016a, 2016b, 2017; Peterson
et al., 2018) or no impact on either outcome (yokum et al., 2017).

while the extant BwC literature is robust, mixed findings underscore areas of inquiry
that warrant further exploration. For example, most studies have examined the immediate
effects of BwC programs after their implementation, while less is known about how they
impact officer behaviors and police–community interactions over time. There is also lim-
ited research on how department-wide adoption of BwCs affects policing outcomes as
more and more officers are equipped with the technology. The current study contributes to
the current body of research by using a quasi-experimental, panel analysis design to exam-
ine the effects of BwCs and how these change over time. we use data from the Milwaukee
Police Department (MPD), which deployed cameras to all eligible officers in a four-phased
rollout. This study aims to inform practice as agencies are still learning how best to deploy
BwCs, create procedures and policies guiding implementation, and incorporate cameras
and footage into operational activities, officer management, and training. This, ultimately,
can help departments improve outcomes related to officer behavior and police–community
interactions and inform budgetary decisions around their BwC programs.

literatUre revieW

BwCs are increasingly being used by police departments across the world under the
assumption that they can improve transparency, accountability, and policing activities. Two


of the most widely used and relevant metrics of BwC effectiveness have been changes in
the number of use of force incidents and citizen complaints. Regardless of whether they
were justified or validated, both uses of force and citizen complaints are undesirable out-
comes in police–community interactions. Thus, both outcomes are used in the literature as
proxies for public accountability, perceptions of trust, and police misbehavior. Still, current
research on the relationship between BwCs and these outcomes is mixed.

Use of force

Studies on the effect of BwCs on use of force have produced inconsistent findings and
have been difficult to disentangle (Lum et al., 2019). In one of the pioneering studies on the
topic, officers in Rialto, California, were randomly assigned to either wear a BwC or con-
tinue their shifts as usual without a camera. The researchers observed that shifts without
BwCs had twice as many use of force incidents as shifts with BwCs (Ariel et al., 2015;
Farrar & Ariel, 2013). Similarly, in a randomized controlled trial (RCT) with 416 officers
from the Las Vegas Police Department, researchers found a 12.5% reduction in use of force
for officers equipped with BwCs (Braga et al., 2017). BwC-equipped officers in Orlando,
Florida, were found to have 5.0% fewer use of force incidents than the control group
(Jennings et al., 2017).

Despite these promising findings, other studies have found nonsignificant and inconclu-
sive effects of BwCs on police use of force. For example, the results from studies in
washington, DC (yokum et al., 2017) and Milwaukee (Peterson et al., 2018) reveal that
BwCs did not impact officers’ levels of use of force. Ariel et al. (2016b) conducted a mul-
tisite analysis of 10 RCTs by shift and found that on average, BwCs had no effect on use of
force incidents. while changes in use of force varied across geographical areas, there was
no evident impact overall. To examine this further, Ariel et al. (2016a) placed each of the 10
departments into groups according to officer’s compliance with the assigned experimental
condition. The results were mixed: Use of force decreased in departments where officers
wore the BwCs in compliance with their assignment in the experiment; however, no effect
was found in the departments where officers had full discretion on when to wear the BwCs,
for both experimental groups.

citizen comPlaints

Citizen complaints have been used in studies as a proxy measure for public perception of
police legitimacy, satisfaction with police performance, and other justice-related outcomes
(Ariel et al., 2015; Liederbach et al., 2008; Pate & Friddell, 1993). Early research has gener-
ally demonstrated large reductions in citizen complaints when evaluating the impact of
BwCs on officer behavior. Specifically, there was a 40% reduction among offers wearing
head cameras in Plymouth, England (Goodall, 2007); a 23% decline in Phoenix, Arizona
(Katz et al., 2014); a 90% decrease in Rialto, California (Ariel et al., 2015); a 65% decline
in Orlando, Florida (Jennings et al., 2015); an 11.5% decrease on the Isle of wight, UK
(Ellis et al., 2015); 51% fewer BwC-equipped officers with complaints than control group
officers in Milwaukee, wisconsin (Peterson et al., 2018); and a 2.5% reduction in the likeli-
hood of U.K. officers receiving a complaint when wearing a BwC (Owens & Finn, 2018).
Using data across a 10-site RCT, Ariel et al. (2017) found a 93% reduction in citizen com-
plaints from before the BwC intervention to after it was fully implemented. One notable


exception to these findings was a large RCT conducted in washington D.C., where the
researchers found no association between cameras and complaints (yokum et al., 2017).

More recent studies have yielded additional information about the effect of BwCs on
complaint reduction. For example, results from the Las Vegas Metropolitan Police
Department found that BwCs reduce about one complaint per officer. These results were
derived from data from between both the treatment and control groups over the preinterven-
tion and intervention phases (Braga et al., 2017). Another study found that not only did
complaints against BwC-equipped officers decline, but that those who did receive com-
plaints while wearing the camera were less likely to have that complaint sustained (Katz
et al., 2015). Finally, findings from another study suggest that the public’s satisfaction with
a police interaction, and therefore their likelihood to lodge a complaint, may be more influ-
enced by whether the officer showed elements of procedural justice regardless of whether
they had a BwC (McClure et al., 2017).

A key issue with examining the relationship between BwCs, police behavior, and citizen
complaints is the already low incident rate of complaints. Small changes to the raw counts
of complaints can result in large percentage changes. This was the case in Arlington, Texas,
during 2015–2016 where researchers found that citywide complaints were reduced by 5.3%
but overall complaints climbed 4.1% when officers equipped with a BwC were removed
(Police Executive Research Forum [PERF], 2017).

the effects of BWcs over time

Most prior studies on use of force and complaints have examined the overall or average
change in officers’ behaviors after they are equipped with a camera, but there is limited
information on the degree to which these effects vary over time. we propose two hypothe-
ses to guide an examination of these effects over time. First, the “program maturity hypoth-
esis” suggests that BwCs increase in their effectiveness as officers become more comfortable
with the technology, develop muscle memory, and accept them as a part of everyday prac-
tice. Gaub and colleagues (2016) compared officer perceptions of BwCs in three police
departments before and after implementation of a BwC program. Across all departments,
officers were more likely to report that the technology was easy to use and comfortable to
wear after implementation of the program, whereas officers in two departments were more
likely to report that BwCs made their jobs easier and were received well by coworkers
(Gaub et al., 2016). A study in the Los Angeles Police Department also found that officers
were more likely to believe that BwCs were easy to use and comfortable to wear post-BwC
deployment (wooditch et al., 2020). Relatedly, a study by Lawrence and colleagues (2019)
examined BwC activation levels and found that officers increased BwC use month-over-
month across all policing activities, indicating that officers were more comfortable and
familiar with the technology over time.

As familiarity and acceptance of BwC technology grow, police supervisors may also
become more effective and efficient at using the technology to manage officers. For exam-
ple, sergeants may increasingly pull and review officers’ BwC footage, address specific
behavioral problems, and proactively identify areas for improvement. Once officers realize
how camera footage is used to correct these issues, they will gradually adjust their behaviors,
including limiting negative or potentially volatile interactions with community members.
Thus, the program maturity hypothesis suggests that BwCs will become more effective at
improving officer behavior and, specifically, reducing use of force and complaints over time.


Conversely, the “program fatigue hypothesis” assumes that BwCs could become less
effective over time as officers adapt their behaviors and the novelty of the cameras wears
off. A study in Phoenix, Arizona, found that officer activation of BwCs varied significantly,
but the rate of activations was highest in the month immediately after officers received
cameras (Katz et al., 2015). Despite their promise as a supervisory tool, most departments
do not regularly, proactively review footage to identify potential issues in officer behavior.
If officers do not notice a change in the department and the behaviors of their colleagues
after implementation of the BwC program, it is unlikely BwCs will change officers’ behav-
iors that may result in a use of force incident or complaint, regardless of how long they are
equipped with a camera.

Program fatigue may also occur if officers become disgruntled with the technology over
time for failing to live up to their expectations. For instance, Gaub and colleagues (2016)
found that officers in three departments were less likely to believe BwCs would make citi-
zens cooperative and respectful after implementation of the BwC program. wooditch et al.
(2020) similarly found that some officers were less likely to believe BwCs could increase
public trust after being equipped with a camera. Improved cooperation, respect, and trust
have been the central justifications for departments to purchase and deploy these devices.
Therefore, if officers are not seeing these benefits in their interactions with community
members, departments may lose the buy-in of their officers and see declines in the overall
effectiveness of the technology. Thus, even if officers initially adjust their behaviors in
response to being equipped with a BwC, they may revert to their pre-BwC routines after a
period. In this situation, the program fatigue hypothesis would suggest that the effectiveness
of BwCs at improving officer behavior, use of force incidents, and complaints would
diminish over time.

Although not a direct test of these competing hypotheses, Sutherland and colleagues
(2017) conducted a 3-year follow-up study from the first RCT of police BwCs in the Rialto
Police Department. Using an interrupted time series design, the authors incorporated rates
of use of force and complaints during an arrest for the year before the experiment, the
experimental year, and 3 years after the experiment. Results showed that initial rates of
complaints against police and use of force during arrest were sustained in the 4 years fol-
lowing the introduction of the cameras (Sutherland et al., 2017). These findings suggest that
persistence, rather than fade-out effects, may characterize the long-term impact of BwCs.

A related consideration of the time-variant effects of BwCs is how departments imple-
ment their programs. Many departments have chosen to pilot their BwC programs with a
select group of officers and gather preliminary information on their utility and effectiveness
before determining whether to deploy them department wide. As such, most studies have
used a small group of officers within the department (e.g., Ariel et al., 2015; Gaub et al.,
2016; Grossmith et al., 2015; Jennings et al., 2015, 2017; Katz et al., 2014; Sutherland
et al., 2017; white et al., 2018) or split the full department into a treatment and comparison
group (wallace et al., 2018). There has been less research to date on how the department-
wide implementation of a BwC program affects officer behavior (for an exception, see
Sutherland et al., 2017).

A department-wide rollout of a BwC program has further implications for our two
hypotheses. Under the program maturity hypothesis, officers will become more comfort-
able or supportive of BwCs as more of their colleagues are equipped with the technology
and it becomes routine practice for all officers. As more officers become equipped with a


BwC, individuals may increasingly believe that their interactions will be recorded by their
colleagues even if they do not activate their own camera. Thus, it is possible that BwC
programs become more generally effective at deterring officer misbehaviors (e.g., unjusti-
fied use of force incidents and negative interactions with community members) as a greater
number of officers in the department receive cameras.

Conversely, and in line with the program fatigue hypothesis, it becomes harder for super-
visors to monitor compliance and use BwCs to manage officer behavior as more officers in
the department are equipped with the devices. This may be particularly true in jurisdictions
where BwCs were rolled out so quickly that department did not create a robust policy for
addressing noncompliance or prescribing how supervisors should review and proactively
use footage. If officers believe they and their colleagues can get away with not using the
cameras as specified in the department’s policy, or if they realize that cameras are not rou-
tinely used by supervisors to correct or reinforce behaviors, it is unlikely that BwCs will
have a lasting, widespread impact on use of force incidents or complaints.

cUrrent stUDy

The current study seeks to build on prior research by examining the effects of BwCs on
officer use of force incidents and citizen complaints over time in an agency that rapidly
deployed BwCs to all its patrol officers. Specifically, we aim to test the following

hypothesis 1 (h1): BwCs will reduce citizen complaints against officers. we expect our findings
to be in line with existing research, which has consistently found that officers equipped with
BwCs are less likely to have a complaint lodged against them than officers without a camera
(Ariel et al., 2016a, 2016b, 2017; Braga et al., 2017; Ellis et al., 2015; Goodall, 2007; Jennings
et al., 2017; Katz et al., 2014).

hypothesis 2 (h2): BwCs will have no overall impact on use of force incidents. Based on numer-
ous recent studies that have found no relationship between cameras and use of force (Ariel
et al., 2016a, 2016b; white et al., 2018; yokum et al., 2017), we similarly expect there to be no
overall impact of BwCs on these incidents.

hypothesis 3 (h3): BwCs will become more effective at reducing use of force and citizen com-
plaints over time. To test the above-stated program maturity hypothesis, we hypothesize that
BwCs will reduce use of force incidents and complaints more so the longer officers are
equipped with cameras. Although we do not expect to see any immediate or overall relation-
ship between BwCs and use of force, it is possible that BwCs will become more effective as
the program matures. In addition, although we expect to see an overall decrease in complaints,
this reduction may be more pronounced over time.

hypothesis 4 (h4): BwCs will become less effective at reducing use of force and citizen com-
plaints over time. Competing with H3, we will also test the program fatigue hypothesis. Under
this hypothesis, we anticipate that BwCs will be less effective at reducing complaints and use
of force incidents the longer officers wear BwCs. For instance, although we expect to see an
overall decrease in citizen complaints, we would find support for this hypothesis if that effect
becomes null or reverses over time.

To test these hypotheses, we used data collected through an evaluation of the MPD’s
BwC program, including information on personnel, officer demographics, use of force
incidents, and citizen complaints. Milwaukee is the largest city in wisconsin, with a diverse


population of nearly 599,000 people in 2016, including 36% white, 38.8% Black, and
18.2% Hispanic (U.S. Census Bureau, 2018). The city’s BwC program developed out of
two issues. First, the city has historically suffered from high crime rates. In 2016,
Milwaukee’s violent crime was 153.30 per 10,000 people, whereas its property crime rate
was 406.40 per 10,000 people. This was the eighth highest violent crime rate and third high-
est property crime rate in cities with a population of 100,000 or more in the country (Federal
Bureau of Investigation [FBI], 2017). The MPD also launched a number of other initiatives
around the same time as their BwC program, such as the Public Safety Partnership and
Project Safe Neighborhoods programs (Brackens & Miller, 2017; U.S. Attorney’s Office,
2019). Both efforts had a heavy focus on reducing gun violence and making areas safer
through community partnerships.

Second, the MPD faced steep challenges building trust among community residents,
particularly in communities of color, in the years prior to implementing their BwC pro-
gram. These issues came to a head in 2014 when an MPD officer shot and killed Dontre
Hamilton. Mr. Hamilton suffered from schizophrenia and paranoia and had fallen asleep on
a park bench when an officer confronted him. After Mr. Hamilton became aggressive, the
MPD officer shot him 14 times. Although the officer was fired, he was not charged with a
crime, which sparked a series of protests across the city (Rogan, 2018). This event, coupled
with the department’s focus on reducing crime, was the impetus for their BwC program.

Under increased pressure from the public and city officials, the MPD launched their
BwC program rather quickly. They developed their BwC policy in mid-2015 and were
tasked with deploying BwCs to all patrol officers by the end of 2016. To best meet this
deadline, the MPD deployed cameras in four waves. wave 1 occurred in October 2015,
where the MPD equipped 182 officers from the Neighborhood Task Force (a group of offi-
cers charged with conducting traffic stops and other proactive activities) and one district
(District 5) with cameras. This served as a pilot test so the MPD could identify and address
technological challenges and incorporate officer feedback into future trainings. wave 2
occurred in March, 2016, during which a random and representative selection of 268 offi-
cers across all remaining districts (Districts 1–4 and 6–7) received their cameras. wave 3
similarly involved 238 more randomly selected officers from across the department being
equipped with BwCs in June 2016. wave 4 occurred in November 2016, and resulted in all
remaining eligible officers (n = 423) receiving their cameras. The staggered BwC rollout
ensured MPD had the capabilities and capacity to train and equip the officers assigned to
each wave. Officers were required to receive a BwC once selected for a phase and were not
able to join or postpone to another phase.

All officers received in-person training by the MPD sergeant who was managing the
BwC program. They were equipped with the Axon Flex 2 BwC model, which are small
devices that officers had the option to mount on their head, collar, or shoulder. As is the case
with all current body camera models, these devices require officers to activate them during
encounters with community members. However, this particular model from Axon has a
small buffering period that captures video of the 30 s immediately before the officer turns
the camera on, although they do not capture audio during this period. The MPD’s BwC
policy requires officers to wear the cameras “at all times when on duty and performing or
likely to perform enforcement duties” (MPD, 2019, p. 4). The policy also prescribes that
officers shall activate their cameras during nearly all community encounters, such as vehi-
cle stops, field interviews and pedestrian stops, searches of persons or property, calls for


service, suspect/witness statements and interviews, and so on. One exception is that officers
have discretion to turn off or not activate their cameras during potentially sensitive events
or circumstances (when interviewing victims of a sexual assault, children, etc.).

The MPD’s BwC program was partially supported by funding from the U.S. Department
of Justice through the Bureau of Justice Assistance’s (BJA) Strategies for Policing Innovation
program. This funding also supported our evaluation of the BwC program and partnership
with the MPD.


we collected data on the MPD officers who received a BwC during the four waves of
the department’s BwC rollout, which included all officers assigned to patrol or similar
duties. Officers were excluded by MPD from the BwC program if they were assigned to
limited duty or administrative positions (positions that involve answering phones, observ-
ing surveillance cameras, etc.). Officers with a rank of lieutenant or higher were also
excluded from the program because they have limited interactions with the public. If an
officer was equipped with a BwC, but was later reassigned or promoted into a position that
no longer required a camera, we retained them in the analyses and tracked the change. Of
the 1,772 sworn officers employed by Milwaukee at the time of our analyses, 1,268 served
a patrol function and were equipped with a camera during the MPD’s deployment. we fur-
ther limited our analytic sample to officers who were consistently employed by the MPD
between January 1, 2015, and June 30, 2017, excluding new recruits hired during this period
and officers who retired or were fired between these months (n = 192). we also excluded
67 officers due to missing demographic and outcome data.

This resulted in a full analytic sample of 1,009 officers. we then transformed these data into
a panel data set so that use of force incidents and citizen complaints were aggregated into
monthly counts for 30 unique, 1-month periods (i.e., each month between January 2015 and
June 2017). This allowed us to generate baseline data on these outcomes (i.e., several months
of use of force and complaint data before officers began receiving BwCs) and provided a way
to measure changes in the effects of BwCs on these outcomes over time. The final data set
offered us with a range of baseline and follow-up data for each officer. Those who received a
camera in wave 1 of deployment (October 2015) had 9 months of baseline data and 21 months
of follow-up after being equipped with a BwC, compared with 22 months of baseline and 8
months of follow-up data for officers who received cameras in wave 4 (November 2016).


The current study examines two outcomes. First, we created a measure of the monthly
count of use of force incidents per officer. A use of force is defined by departmental policy
in Milwaukee and includes incidents ranging from physically subduing an individual who
is not complying with officers’ commands to discharging a weapon and deadly force.

we also examine the monthly counts of citizen complaints against each officer. People in
Milwaukee may lodge a complaint against an officer by phone or in person with a supervi-
sor at any of the …

This resource was written by Purdue OWL.

Sentence Variety

Strategies for Variation

Adding sentence variety to prose can give it life and rhythm. Too many sentences with the same

structure and length can grow monotonous for readers. Varying sentence style and structure can also

reduce repetition and add emphasis. Long sentences work well for incorporating a lot of information,

and short sentences can often maximize crucial points. These general tips may help add variety to

similar sentences.

1. Vary the rhythm by alternating short and long sentences.

Several sentences of the same length can make for bland writing. To enliven paragraphs, write

sentences of different lengths. This will also allow for effective emphasis.

Example: The Winslow family visited Canada and Alaska last summer to find some native

American art. In Anchorage stores they found some excellent examples of soapstone

carvings. But they couldn’t find a dealer selling any of the woven wall hangings they

wanted. They were very disappointed when they left Anchorage empty-handed.

Revision: The Winslow family visited Canada and Alaska last summer to find some native

American art, such as soapstone carvings and wall hangings. Anchorage stores had many

soapstone items available. Still, they were disappointed to learn that wall hangings,

which they had especially wanted, were difficult to find. Sadly, they left empty-


Example: Many really good blues guitarists have all had the last name King. They have

been named Freddie King and Albert King and B.B. King. The name King must make a

bluesman a really good bluesman. The bluesmen named King have all been very talented

and good guitar players. The claim that a name can make a guitarist good may not be

that far fetched.

Revision: What makes a good bluesman? Maybe, just maybe, it’s all in a stately name.

B.B. King. Freddie King. Albert King. It’s no coincidence that they’re the royalty of

their genre. When their fingers dance like court jesters, their guitars gleam like

scepters, and their voices bellow like regal trumpets, they seem almost like nobility.

Hearing their music is like walking into the throne room. They really are kings.

2. Vary sentence openings.

If too many sentences start with the same word, especially “The,” “It,” “This,” or “I,” prose can grow

tedious for readers, so changing opening words and phrases can be refreshing. Below are alternative

openings for a fairly standard sentence. Notice that different beginnings can alter not only the

structure but also the emphasis of the sentence. They may also require rephrasing in sentences before

or after this one, meaning that one change could lead to an abundance of sentence variety.

Example: The biggest coincidence that day happened when David and I ended up sitting

next to each other at the Super Bowl.

Possible Revisions:

 Coincidentally, David and I ended up sitting right next to each other at the

Super Bowl.

 In an amazing coincidence, David and I ended up sitting next to each other at

the Super Bowl.

 Sitting next to David at the Super Bowl was a tremendous coincidence.

 But the biggest coincidence that day happened when David and I ended up sitting

next to each other at the Super Bowl.

 When I sat down at the Super Bowl, I realized that, by sheer coincidence, I was

directly next to David.

 By sheer coincidence, I ended up sitting directly next to David at the Super


 With over 50,000 fans at the Super Bowl, it took an incredible coincidence for

me to end up sitting right next to David.

 What are the odds that I would have ended up sitting right next to David at the

Super Bowl?

 David and I, without any prior planning, ended up sitting right next to each

other at the Super Bowl.

 Without any prior planning, David and I ended up sitting right next to each

other at the Super Bowl.

 At the crowded Super Bowl, packed with 50,000 screaming fans, David and I ended

up sitting right next to each other by sheer coincidence.

 Though I hadn’t made any advance arrangements with David, we ended up sitting

right next to each other at the Super Bowl.

 Many amazing coincidences occurred that day, but nothing topped sitting right

next to David at the Super Bowl.

 Unbelievable, I know, but David and I ended up sitting right next to each other

at the Super Bowl.

 Guided by some bizarre coincidence, David and I ended up sitting right next to

each other at the Super Bowl.

Sentence Types

Structurally, English sentences can be classified four different ways, though there are endless

constructions of each. The classifications are based on the number of independent and dependant

clauses a sentence contains. An independent clause forms a complete sentence on its own, while a

dependent clause needs another clause to make a complete sentence. By learning these types, writers

can add complexity and variation to their sentences.

Simple sentence: A sentence with one independent clause and no

dependent clauses.

 My aunt enjoyed taking the hayride with you.

 China’s Han Dynasty marked an official recognition of Confucianism.

Compound Sentence: A sentence with multiple independent clauses but no

dependent clauses.

 The clown frightened the little girl, and she ran off screaming when she saw


 The Freedom Riders departed on May 4, 1961, and they were determined to travel

through many southern states.

Complex Sentence: A sentence with one independent clause and at least

one dependent clause.

 After Mary added up all the sales, she discovered that the lemonade stand was

32 cents short

 While all of his paintings are fascinating, Hieronymus Bosch’s triptychs, full

of mayhem and madness, are the real highlight of his art.

Complex-Compound Sentence: A sentence with multiple independent

clauses and at least one dependent clause.

 With her reputation on the line, Peggy played against a fierce opponent at the

Scrabble competition, and overcoming nerve-racking competition, she won the game

with one well-placed word.

 Catch-22 is widely regarded as Joseph Heller’s best novel, and because Heller

served in World War II, which the novel satirizes, the zany but savage wit of the

novel packs an extra punch.

For Short, Choppy Sentences

If your writing contains lots of short sentences that give it a choppy rhythm, consider these tips.

1. Combine Sentences With Conjunctions:

Join complete sentences, clauses, and phrases with conjunctions:

and, but, or, nor, yet, for, so

Example: Doonesbury cartoons satirize contemporary politics. Readers don’t always find

this funny. They demand that newspapers not carry the strip.

Revision: Doonesbury cartoons laugh at contemporary politicians, but readers don’t

always find this funny and demand that newspapers not carry the strip.

2. Link Sentences Through Subordination:

Link two related sentences to each other so that one carries the main idea and the other is no longer a

complete sentence (subordination). Use connectors such as the ones listed below to show the


after, although, as, as if, because, before, even if, even though, if, if only, rather

than, since, that, though, unless, until, when, where, whereas, wherever, whether,

which, while

Example: The campus parking problem is getting worse. The university is not building

any new garages.

Revision: The campus parking problem is getting worse because the university is not

building any new garages.

Example: The US has been highly dependent on foreign oil for many years. Alternate

sources of energy are only now being sought.

Revision: Although the US has been highly dependent on foreign oil for many years,

alternate sources are only now being sought.

Notice in these examples that the location of the clause beginning with the dependent marker (the

connector word) is flexible. This flexibility can be useful in creating varied rhythmic patterns over the

course of a paragraph.

For Repeated Subjects or Topics

Handling the same topic for several sentences can lead to repetitive sentences. When that happens,

consider using these parts of speech to fix the problem.

1. Relative pronouns

Embed one sentence inside the other using a clause starting with one of the relative pronouns listed


which, who, whoever, whom, that, whose

Example: Indiana used to be mainly an agricultural state. It has recently attracted

more industry.

Revision: Indiana, which used to be mainly an agricultural state, has recently

attracted more industry.

Example: One of the cameras was not packed very well. It was damaged during the move.

Revision: The camera that was not packed very well was damaged during the move.

Example: The experiment failed because of Murphy’s Law. This law states that if

something can go wrong, it will.

Revision: The experiment failed because of Murphy’s Law, which states that if

something can go wrong, it will.

Example: Doctor Ramirez specializes in sports medicine. She helped my cousin recover

from a basketball injury.

Revision 1: Doctor Ramirez, who specializes in sports medicine, helped my cousin

recover from a basketball injury.

Revision 2: Doctor Ramirez, whose specialty is sports medicine, helped my cousin

recover from a basketball injury.

2. Participles

Eliminate a be verb (am, is, was, were, are) and substitute a participle:

Present participles end in -ing, for example: speaking, carrying, wearing, dreaming.

Past participles usually end in -ed, -en, -d, -n, or -t but can be irregular, for

example: worried, eaten, saved, seen, dealt, taught.

Example: Wei Xie was surprised to get a phone call from his sister. He was happy to

hear her voice again.

Revision 1: Wei Xie, surprised to get a phone call from his sister, was happy to hear

her voice again.

Revision 2: Surprised to get a phone call from his sister, Wei Xie was happy to hear

her voice again.

3. Prepositions

Turn a sentence into a prepositional phrase using one of the words below:

about, above, across, after, against, along, among, around, as, behind, below,

beneath, beside, between, by, despite, down, during, except, for, from, in, inside,

near, next to, of, off, on, out, over, past, to, under, until, up, with

Example: The university has been facing pressure to cut its budget. It has eliminated

funding for important programs. (two independent clauses)

Revision: Under pressure to cut its budget, the university has eliminated funding for

important programs. (prepositional phrase, independent clause)

Example: Billy snuck a cookie from the desert table. This was against his mother’s


Revision: Against his mother’s wishes, Billy snuck a cookie from the desert table.

For Similar Sentence Patterns or Rhythms

When several sentences have similar patterns or rhythms, try using the following kinds of words to

shake up the writing.

1. Dependent markers

Put clauses and phrases with the listed dependent markers at the beginning of some sentences

instead of starting each sentence with the subject:

after, although, as, as if, because, before, even if, even though, if, in order to,

since, though, unless, until, whatever, when, whenever, whether, and while

Example: The room fell silent when the TV newscaster reported the story of the


Revision: When the TV newscaster reported the story of the earthquake, the room fell


Example: Thieves made off with Edvard Munch’s The Scream before police could stop


Revision: Before police could stop them, thieves made off with Edvard Munch’s The


2. Transitional words and phrases

Vary the rhythm by adding transitional words at the beginning of some sentences:

accordingly, after all, afterward, also, although, and, but, consequently, despite,

earlier, even though, for example, for instance, however, in conclusion, in contrast,

in fact, in the meantime, in the same way, indeed, just as… so, meanwhile, moreover,

nevertheless, not only… but also, now, on the contrary, on the other hand, on the

whole, otherwise, regardless, shortly, similarly, specifically, still, that is, then,

therefore, though, thus, yet

Example: Fast food corporations are producing and advertising bigger items and high-

fat combination meals. The American population faces a growing epidemic of obesity.

Revision: Fast food corporations are producing and advertising bigger items and high-

fat combination meals. Meanwhile, the American population faces a growing epidemic of



Journal of Quantitative Criminology

1 3


Do Police Body‑Worn Cameras Reduce Citizen Fatalities?
Results of a Country‑Wide Natural Experiment

Joel Miller1  · Vijay F. Chillar1

Accepted: 21 April 2021
© The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2021

Objectives This study assesses the effects of body-worn cameras (BWCs) on rates of fatal-
ities arising from police-citizen encounters. While existing experimental research has not
examined this outcome because it is so rare, the staggered roll-out of BWCs across the
nation’s law enforcement agencies provides an opportunity for quasi-experimental analysis.
Methods Difference-in-difference (DID) analyses using Poisson models compare changes
in U.S. law enforcement agencies’ fatality counts with changes in BWC acquisition. Using
a federal law enforcement survey focused on body worn cameras (LEMAS-BWCS) and
media-sourced data on fatal encounters from fatalencounters.org (FE), the research exam-
ines agencies acquiring BWCs between 2013/14 and 2015/16 and those that did not acquire
them up to 2016 and had no plans to do so. It includes a fixed effects annual panel data
analysis with data from 2005/06 to 2018/19 and two two-group analyses focusing on a pre-
treatment period (2010/11 to 2012/13) and a post-treatment period (2016/17 to 2018/19).
The latter includes a propensity score matched comparison.
Results Two out of three DID analyses showed statistically significant negative effects of
BWCs on citizen fatalities. The propensity score matched two-group analysis returned a
non-significant negative effect.
Conclusions The research finds some evidence for BWC effects on citizen fatalities. How-
ever, there are important validity threats to this conclusion. These include the possibility
that BWC acquisition serves as a marker for other policy changes focused on BWC-acquir-
ing agencies in the 2013/14 to 2015/16 period and beyond.

Keywords Body-worn cameras · Fatal encounters · Police technology · Use of force ·

* Joel Miller
[email protected]

1 School of Criminal Justice, Center for Law and Justice, Rutgers University, 123 Washington Street
Suite 549, Newark, NJ 07102, USA

Journal of Quantitative Criminology

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In the summer of 2014, the fatal police shooting of Michael Brown in Ferguson Mis-
souri reignited a fierce national debate about the prevalence of fatal outcomes from police
encounters in the United States (U.S.), particularly among black men (Sherman 2018).
Anger about police killings has been fueled since then by the steady stream of stories
of others killed in police interactions, including those fatally shot (such as Tamir Rice,
Laquan McDonald, and Breonna Taylor) and those dying in other forms of police confron-
tation (such as Freddie Gray and Daniel Prude). Outrage was reenergized in the summer of
2020 with the killing of George Floyd, under the knee of a Minneapolis police officer, lead-
ing to a fresh wave of country-wide protests.

It transpires that U.S. rates of fatal encounters are unparalleled in the western world.
American police kill an average of three people daily (Guardian 2017), with rates of fatal
police shootings in the U.S. about 18 times higher than Denmark, 38 times higher than
Germany, and 200 times higher than England and Wales (Hirschfield 2015b). Research by
Edwards et al. (2019) has recently calculated that the lifetime risks of mortality from police
use-of-force for black males at about 1 in 1,000, and 1 in 2,000 for males in general. This
places police use of force as one of the leading causes of death in these groups: for males
between the ages of 25 and 29, it ranked sixth, behind accidents, suicide, other homicides,
heart disease and cancer (Edwards et al. 2019).1

U.S. exceptionalism in its rates of fatal encounters likely reflect differences in gun laws,
gun culture, and welfare policies (Hirschfield 2015a, b). However, explanations likely
also owe something to the way police agencies operate, including their policies, training,
and supervision (Alpert and MacDonald 2001; Fyfe 1988; Hickman and Piquero 2009;
Nowacki 2015; Shjarback and White 2016). Recognizing this, and responding to the recent
public outcry, many police leaders and legislatures have sought to strengthen police organi-
zational policies to limit their reliance on lethal force (Police Executive Research Forum
[PERF], 2016; President’s Task Force 2015; Subramanian and Skrzypiec 2017).

In this context, body-worn cameras (BWCs) have featured as an important compo-
nent of many new policies, rapidly expanding among police departments in recent years
(Hyland 2018). These small devices, worn on the officers’ person (such as their clothing,
sunglasses, or helmet) coupled with a system of data storage that can facilitate replay of
the video recorded at a later time, offer the prospect of improving officer behaviors dur-
ing encounters, and building trust between community and police (Lum et al. 2019; White

While the initial push for BWCs took place in the absence of much evaluation evidence,
the situation has since evolved with a burgeoning body of evaluation literature now avail-
able (Lum et  al. 2019) alongside toolkits (Bureau of Justice Assistance, n.d.) and tech-
nical assistance programs (Body Worn Camera Training and Technical Assistance, n.d.)
for practitioners wishing to implement BWCs. Yet, while evaluations of BWCs examine
a variety of outcomes, we are not aware of a single study that has assessed their effects
on citizen fatalities. Given the role these fatalities have played in the push for BWCs, this
is perhaps surprising. However, it pragmatically reflects the methodological challenges
of conducting such research. Fatal encounters are extremely rare in the context of routine

1 It is notable that the racial disparities in deaths from use of force echo larger disparities in homicides gen-
erally, with black homicide rates 7.31 times greater than white homicide rates in 2016 age-adjusted com-
parisons (Centers for Disease Control and Prevention, n.d.).

Journal of Quantitative Criminology

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police-public interactions and provide limited statistical power to support analysis in site-
specific evaluations.

The current study seeks to overcome these methodological challenges, and to help fill
the gap in research. It does so by exploiting the staggered acquisition of BWC systems
across thousands of U.S. law enforcement agencies in recent years, as measured in a 2016
Bureau of Justice Statistics (BJS) survey of law enforcement agencies (U.S. BJS 2016). By
comparing these data with national media-based records of police fatal encounters, a series
of difference-in-difference (DID) analyses are used to generate quasi-experimental insights
about the effects of BWCs on fatal encounters.

Literature and Theory

Understanding Police Fatal Encounters

We define fatal encounters as police contacts with the public in which police actions plau-
sibly contribute to the death of the subject. While these can involve non-lethal force, medi-
cal emergencies, or mental health issues, they predominantly involve the police shooting of
suspects.2 And, while they are relatively frequent in the U.S. compared to other countries,
they are nonetheless extremely rare events within the context of routine policing (Sherman
2018). Numbering roughly a thousand each year (Guardian 2017), they contrast in magni-
tude with the 53.5 million people experiencing at least one police-initiated encounter annu-
ally (Davis et al. 2018).

White (2002) has highlighted the importance of environmental, organizational, and situ-
ational influences in explaining use of deadly force, and these levels of explanation likely
have lessons for fatal encounters generally. Environmental factors include community-level
characteristics, for example with use of deadly force associated with violent crime (Kania
and Mackey 1977; Fyfe 1980). They also include external efforts to control deadly force
discretion, such as court rulings and state laws which have been shown to influence use of
deadly force (e.g., Tennenbaum 1994).

Organizational influences on fatal encounters include administrative policies, such as
those introduced in the New York Police Department in the 1970s, which reduced officer
shootings (Fyfe 1978) as well as similar policies elsewhere (Fyfe 1988; Geller and Scott
1992; White 2002). They additionally encompass organizational leadership which have
their own influence on use of force (Fyfe 1982; Sherman 2018; White 2001) and police
subcultures may also be influential (Wong and Bibring 2017; Marenin 2016).

Fatal encounters are also a product of situational factors. While the majority of suspects
who are shot present some significant physical threat to the police (Fyfe 1980; Klinger
et  al. 2016; Klinger and Slocum 2017), fatal outcomes also depend on a range of situ-
ational dynamics, including the suspect and officer’s actions and the options available to

2 Randomly drawing 50 encounters between May 2005 and April 2019 from the fatalencounters.org data-
base (excluding vehicle-related, deaths, deaths involving multiple law enforcement agencies, or deaths asso-
ciated with federal or corrections agencies), we found that all 50 cases involved some officer use of force.
Officers shot at the suspect in 43 out of 50 cases, tasered them in 4 cases, used a stun gun in one case, used
flashbang grenades and teargas in one case, and engaged in a physical struggle in two cases. In 21 cases,
the victim had a gun, and in 12 further cases they had some other kind of weapon (in 9 cases a bladed
weapon). In two cases, the victim shot themselves. Six encounters involved suspects barricading themselves
in a building (five times with hostages). One case involved an off-duty officer killing a suspect.

Journal of Quantitative Criminology

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the officer (Bayley 1986; Fyfe 1986). Binder and Scharf (1980) and White (2002) describe
how encounters pass through the distinct phases of anticipation, entry, interaction/informa-
tion exchange, force decision, and aftermath, with officers and citizens making decisions
and responses that may escalate or de-escalate the encounter and ultimately affect the like-
lihood of violence. Outcomes will also be influenced by how many shots officers fired (in
police shootings), whether officers render immediate medical care to injured or sick mem-
bers of the public, and whether they call in medical support or transport people to the hos-
pital for those who need it (Zimring 2017).

Policy Responses to Fatal Encounters

The recent explosion of public interest in police fatal encounters reflects a revelation for
many. However, as Sherman (2018) has described, this represents a second “awakening”.
Popular and political interest in excessive shootings by police in the 1970s and 1980s led to
reforms ushered in by progressive police chiefs and civil litigation, and which were associ-
ated with the halving of citizens killed by police across large cities (Sherman et al. 1986).
New policy restrictions limited the shooting of nonviolent suspects and vehicles, and the
use of warning shots (Geller and Scott 1992), and are illustrated in influential research by
Fyfe (1978) in New York. The period of reform gave rise to the 1985 U.S. Supreme Court
decision of Tennessee v. Garner (471U.S.1) that made the killing of fleeing non-violent
suspects unconstitutional, which apparently pushed down justifiable homicides by police
even further (Tennenbaum 1994), seemingly because smaller cities then adopted the policy
for the first time (Sherman 2018).

Subsequently, interest in police shootings faded in the late 1980s, in the wake of the
crack epidemic and rising urban homicide rates (Sherman 2018). The Graham v. Connor
(490U.S.386; 1989) supreme court decision seemed to represent a further step backwards
by granting officers substantial latitude in use of deadly force, ruling they were justified in
killing people if they reasonably believed a life was in danger (Sherman 2018). Police kill-
ings of citizens apparently increased again in the early 1990s (Zimring 2017).

Recent high-profile police killings have spurred a renewed public interest in the issue,
and galvanized calls for police reform, with some effect. Developments included a blue-
ribbon presidential task force in 2015 on “twenty-first century policing”, which issued 59
recommendations that included a focus on building trust and legitimacy and strengthen-
ing policy and oversight (President’s Task Force on 21st Century Policing 2015). In 2016
PERF issued a set of “guiding principles” for use of force, focused on responding to sub-
jects with mental illness and who are not carrying firearms (PERF 2016). A survey of
forty-seven large police departments conducted by the Major Cities Chiefs Association
(MCCA) and the National Police Foundation showed that 39% of them had changed their
use of force policies and incorporated de-escalation and revised scenario-based training
between 2015 and 2017 (Stephens 2019). There were also changes to state legislation, with
15 states passing legislation in 2015 or 2016 to strengthen the regulation and training of
use of force, enhance accountability in use of force cases, or to implement policies relating
to vulnerable populations and crisis intervention (Subramanian and Skrzypiec 2017). In
2017, 21 states required de-escalation training for police (Clarey 2017).

The new reforming trend has been accompanied by a substantial push for BWC adop-
tion by police departments. The President’s 2015 task force final report highlighted BWCs
as a potential tool for improving trust and accountability (President’s Task Force on 21st
Century Policing 2015; White and Coldren 2017). Providing a financial and symbolic

Journal of Quantitative Criminology

1 3

boost to this trend, the DOJ sponsored a BWC Policy and Implementation Program, that
has awarded tens of millions of dollars to local agencies since 2016 to implement BWC
systems (Braga et al. 2018; White et al. 2017). And in 2016 and 2017, half of states intro-
duced legislation to mandate BWC usage in law enforcement (Subramanian and Skrzypiec
2017). Survey evidence from the BJS’ survey of law enforcement (data from which is used
in this article) showed that 47% of police agencies boasted BWC systems in 2016 (Hyland
2018), more than double the number for 2014 (22%) and eight times the number for 2011
(6%; U.S. BJS, 2016).

Effects of BWCs on Policing

The initial push for BWCs took place without a substantial evidence-base concerning
the technology’s efficacy. However, the widespread utilization of BWCs has since cre-
ated opportunities for evaluators to learn. In the most extensive reviews to date, Lum
et al. (2019) analyzed 70 empirical studies on BWCs published through June 2018, which
include many credible experimental and quasi-experimental studies. This was followed by
publication of a Campbell Collaboration review that included results of meta-analysis of
some of these studies (Lum et al. 2020).

The most consistent effect identified by Lum and colleagues’ reviews was a decrease in
the number of complaints against the police when BWCs are used. Notably, meta-analysis
estimated a 16.6% reduction in police complaints (based on 22 study effect sizes; Lum
et al. 2020). While complaints are often seen as a measure of officer behavior, it is unclear
whether these results might also reflect changes in citizen responses to encounters (e.g.,
Koen et  al. 2018; Lum et  al. 2019). Research on BWCs’ effects on officer use of force
specifically—the measure most closely related to our outcome of interest—shows mixed
findings, however (Lum et al. 2019, 2020; Malm 2019). Lum and colleagues’ meta-analysis
(2020) estimated that BWCs reduced use of force overall by just 6.8%, based on 26 eligible
effect sizes, an effect that was not statistically significant. Moreover, despite some concerns
about risks of contamination or “spillover” effects in some experimental designs focused
on BWCs (Ariel et al. 2019), Lum et al. (2020) meta-analysis found no clear effect of con-
tamination risk on use of force effect sizes.

Other BWC effects reviewed by Lum et al. (2019) are mostly inconsistent. For example,
in Lum and colleagues’ meta-analysis (2020), they found only two overall significant BWC
meta-analytic effects from a total 12 outcomes examined. Besides the statistically signifi-
cant reduction in complaints against officers, the only other statistically significant effect
was an increase in numbers of non-traffic citations (based on just two study effect sizes).
Other outcomes, for example in relation to field interviews or stop and frisk, calls for ser-
vice, assaults on officers/officer injuries/resistance, and traffic stops and tickets, showed no
significant overall meta-analytic effects.

Inconsistent study effects of BWCs likely reflect variations in the context and manner
in which they are implemented. White and Malm (2020) have argued that the state of an
agency pre-deployment is a key moderator of BWC effects, affected for example by the
existing accountability mechanisms and political environment into which BWCs are intro-
duced. Similarly, they suggest that planning and implementation processes can also criti-
cally shape BWC outcomes, with resistance among officers a significant risk, and a strong
potential for poorly constructed policies and non-adherence to policies by street officers.
A key negative outcome from poor implementation is the potential for BWCs to be acti-
vated inconsistently in the field. It is notable, furthermore, that moderator analysis in Lum

Journal of Quantitative Criminology

1 3

et  al.’s meta-analysis (2020) shows BWC effects on use of force are stronger when trials
have greater implementation fidelity, and when officers have less discretion with regard to
BWC activation.

How BWCs May Impact Fatal Encounters

Not a single study in Lum and colleagues’ reviews (2019,2020) examined BWCs’ effects
on citizen fatalities. Indeed, given the extreme rarity of these events, there are simply too
few of them to provide adequate statistical power to do so. While the inconsistent evidence
of BWCs’ impacts on use of force generally provides important context when considering
their effects on fatalities (Lum et al. 2019, 2020), we should note that fatal encounters are
atypical of use of force generally. Notably, there are over 700,000 incidents of police use or
threats of force without fatal outcomes each year (Hyland et al. 2015) alongside the roughly
one thousand annual fatal encounters, making these events highly unusual. If BWCs were
to affect use of deadly force and fatal outcomes from policecitizen contacts, we can theo-
rize that they would likely do this through their effects on situational and organizational

Situational Effects

Existing BWC scholarship emphasizes deterrence as the primary mechanism producing
BWC effects. According to this view, BWCs discourage officers, and citizens, from engag-
ing in inappropriate or illegal behavior, because they understand it may be captured on a
video camera that features prominently on officers’ uniforms (Ariel et al. 2017a; Hedberg
et  al. 2017; Koen et  al. 2018; Newell and Greidanus 2017). In particular, the presence of
BWCs is thought to increase the perceived certainty of apprehension for norm violations
(Ariel et  al. 2015). The idea is further underpinned by social psychological studies sug-
gesting that people being observed alter their behavior to coincide with socially accepted
norms, rules, and standards, as part of a “self-awareness effect” (Ariel et al. 2015; Duval
and Wicklund 1972; Munger and Harris 1989; Wedekind and Braithwaite 2002; Wicklund
1975). In practical terms, BWCs may cool down potentially aggressive suspects and offic-
ers (described as a “civilizing effect” [White 2014]) preventing encounters escalating to
the point where officers use force, including deadly force (Ariel et al. 2015), and perhaps
showing more restraint when they do.

Building off insights from Sherman (2018) and Klinger (2005), we might also specu-
late that the deterrence effects of BWCs work to “slow down” police-citizen encounters
in ways that reduce the risk of fatalities. These authors, relying on literature on rare and
catastrophic accidents (Perrow 1984), suggest the risk of these incidents is exacerbated
when systems are complex and involve more “tightly coupled” elements. If BWCs produce
encounters characterized by more self-control and adherence to procedures and norms, as
some studies suggest (Koen et al. 2018; Rowe et al. 2018), this could contribute to a slow-
ing effect, reducing the risk of catastrophic outcomes. However, it is also possible that the
formality produced by BWC could backfire to produce a more rigid, enforcement-oriented
policing (White and Malm 2020), consistent with the raised level of enforcement activity
produced by BWCs in some studies (Lum et al. 2020).

We should also note that BWCs may provide deterrence “upstream” of encounters before
life or death decisions present themselves. Officers concerned about the negative fallout
that may arise in the presence of a BWC might avoid proactivity or respond grudgingly to

Journal of Quantitative Criminology

1 3

calls for service, in turn reducing public interaction and the risk of fatal events. This idea is
consistent with Ariel and colleagues (Ariel et al. 2017a) description of “inertia” as a form
of “over-deterrence” and may be associated with more rigid, bureaucratic styles of BWC
implementation. White and Malm (2020) similarly suggest BWCs may be associated with
a de-policing effect.

Finally, the extent to which police-citizen encounters have fatal outcomes likely owes
something to the timeliness of appropriate first aid and medical response (Zimring 2017).
Indeed, the lack of swiftly administered first aid following shootings has been a source
of significant criticism among some commentators (Perez-Pena 2016; Sherman 2018). We
speculate that these decisions may also be susceptible to BWCs’ deterrent effects, particu-
larly given that such decisions will tend to become relevant after officer danger has passed,
when officers have discretion in how they then follow-up.

Organizational Effects

Beyond their direct deterrent effects, BWCs may have indirect effects on fatal encounters
through their influence on agency policies, practices, and culture (Koen et al. 2018). First,
agencies may use the footage generated through BWCs to enhance police training. The use
of realistic footage may better prepare officers for the kinds of situations they may encoun-
ter on the street. A second possibility involves front-line supervisors using BWCs to facili-
tate supervision (Koen et  al. 2018; White and Malm 2020). By offering a direct window
onto officers’ street level activities and behaviors, hitherto unavailable to them, they may
be better able to review problematic incidents, problem-solve, provide corrective check-
ins, and conduct annual reviews, thus incentivizing and nurturing more professional officer

In addition, we suggest that the implementation of BWCs may serve as a broader sig-
nal to frontline officers, promoting organizational priorities concerning professionalism,
accountability, and respectful treatment of the public. This would not only affect individual
officers wearing a BWC at a particular moment in time, but the broader organization and
staff. This idea is consistent with findings from a multi-site experimental study of BWCs
conducted by Ariel and colleagues (Ariel et al. 2017b). While effects on police complaints
were not evident comparing treatment and control groups, there was a stunning 93% over-
all reduction in complaints across the agency. The authors explain this with reference to
“contagious accountability” whereby officers’ exposure to BWCs—even if they were not
wearing them—reshaped their normative expectations about the appropriate treatment of

Data and Methods


Our analysis focuses on subsamples of U.S. police departments drawn from the BJS’
Law Enforcement Management and Administrative Statistics Body-Worn Camera Sup-
plement (LEMAS-BWCS) fielded in May 2016 (Hyland 2018). We included yearly data
points (May through April) for these agencies, counting forward and backwards from the
beginning of the LEMAS-BWCS survey fieldwork (yearly data points were combined for
some analyses). The survey, which included 3,928 returns  (representing  a response rate

Journal of Quantitative Criminology

1 3

of 79%), targeted state and local police departments and sheriffs’ offices, while exclud-
ing special jurisdictions agencies (such as schools, airports, or parks police), or agencies
with special enforcement responsibilities (such as conservation laws or alcohol laws). It
used a stratified sample design, based on numbers of full and part-time officers, which
would be representative (after weighting) of these law enforcement agencies in the U.S.
In doing so, it targeted all primary state law enforcement agencies, local departments,
and sheriffs’ offices with 100 or more full-time sworn officers, along with probability
samples of smaller agencies (U.S. BJS 2016). The unweighted data, from which we draw
our analytical subsamples, therefore disproportionately represent the experience of larger

Initially, we conducted analyses on most agencies surveyed, bar those agencies that
received BWCs prior to 2006/07 (wishing to avoid earlier years where data on fatal
encounters was less reliable) and for those that we had missing measures. We call this
the “full” study sample, and it totaled 3,514 agencies. However, as we will explain, prob-
lems with assumption violations (and concerns about imputed values on BWC acquisi-
tion) led us to focus attention on a smaller subset of 2,376 agencies that we call here the
“core” sample, made up of 1,346 “treatment” agencies that we know acquired BWCs
only during the period 2013/14 to 2015/2016 and 1,030 “control” agencies that likely did
not acquire them at all between 2005/06 and 2018/19. We then reduced this sample fur-
ther through a propensity score match. This left us with 1,795 agencies (1,178 treatment
and 617 control), which we refer to here as the “matched” sample. As a supplement to
these samples, we also constructed a number of alternative comparison groups that either
aspired to acquire BWCs (and may have done so after the survey) or had acquired them
outside of our focus implementation years of 2013/14 to 2015/16. As we explain later
in the paper, comparing these with the BWC acquiring agencies in the focused sample
help further check inferences about BWC effects. We relied on specific questions within
the LEMAS-BWCS survey to help select agencies according to these various criteria.
Tables 1 and 2 provide details of the research samples, including their demographic char-
acteristics, and their patterns of BWC acquisition and fatal encounters, based on the key
measures discussed below.

Data and Measures

BWC Acquisition

Our primary independent variable is the presence or absence of a BWC system in law
enforcement agencies, by year. It is important to note that this does not speak to any agen-
cy’s level of BWC implementation in any given moment, which will likely vary across
agencies that acquire BWCs (White and Malm 2020)3 We relied primarily on three
LEMAS-BWCS survey questions to develop this variable. The first asked “Has your
agency acquired any of the following tools to record officer-citizen interactions…?” which

3 For the 1,346 agencies in the core sample that had acquired BWCs between 2013/14 and 2015/16, at the
time of the 2016 survey: 50.3% of reported “Full deployment to all intended personnel”, 10.1% reported
“Complete deployment for some assignments / partial deployment in others”, 11.5% reported “Partial
deployment”, 25.6% described “Exploratory/pilot deployment”, 2.3% were unsure, and 3 cases (< 1%) had
missing responses.

Journal of Quantitative Criminology

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APA Formatting and Style Guide

This resource was written by David Neyhart and Erin Karper. Additional material by

Kristen Seas.

Last full revision by Jodi Wagner and Kristen Seas.

Last edited by Dana Lynn Driscoll on June 6th 2007 at 2:25PM

Summary: APA (American Psychological Association) is most commonly used to cite

sources within the social sciences. This resource, revised according to the 5th edition of

the APA manual, offers examples for the general format of APA research papers, in-text

citations, endnotes/footnotes, and the reference page.

General Format

General APA Guidelines

Your essay should be typed, double-spaced on standard-sized paper (8.5 X 11 inches)

with margins of 1 inch on all sides. Your final essay should include, in the order indicated

below, as many of the following sections as are applicable, each of which should begin

on a separate page:

Title page: includes a running head for publication, title, and byline and affiliation.

Page numbers and running head: in the upper right-hand corner of each page, include a

1-2 word version of your title. Follow with five spaces and then the page number.

Abstract: If your instructor requires an abstract, write a 75-100 word overview of your

essay, which should include your main idea and your major points. You also may want to

mention any implications of your research. Place the abstract on its own page

immediately after the title page. Center the word Abstract and then follow with the


Headings: Although not absolutely necessary, headings can be helpful. For

undergraduate papers, only one level of heading is necessary. Major headings should be

centered. Capitalize every word in the heading except articles (a, the), short prepositions

(in, by, for), and coordinating conjunctions (and, but, or).

Visuals: Visuals such as tables and figures include graphs, charts, drawings, and

photographs. Try to keep the visuals as simple as possible and clearly label each visual

with an Arabic numeral (ex: Table 1, Table 2, etc.) and include the title of the visual. The

label and the title should appear on separate lines above the table, flush left. Below the

table, provide the source.

List of References: Create your list of references on its own page after the last page of

your text. Center the title References one inch from the top of the page. Double space.

Alphabetize the list of references by the last name of the authors. If the work has no

author or editor, alphabetize the work by the first word of the title (excluding A, An, or


In-Text Citations: The Basics

Reference citations in text are covered on pages 207-214 of the Publication Manual.

What follows are some general guidelines for referring to the works of others in your


Note: APA style requires authors to use the past tense or present perfect tense when

using signal phrases to describe earlier research. E.g., Jones (1998) found or Jones

(1998) has found…

APA Citation Basics

When using APA format, follow the author-date method of in-text citation. This means

that the author’s last name and the year of publication for the source should appear in the

text, E.g., (Jones, 1998), and a complete reference should appear in the reference list at

the end of the paper.

If you are referring to an idea from another work but NOT directly quoting the material,

or making reference to an entire book, article or other work, you only have to make

reference to the author and year of publication in your in-text reference.

In-Text Citation Capitalization, Quotes, and Italics/Underlining

 Always capitalize proper nouns, including author names and initials: D. Jones.

 If you refer to the title of a source within your paper, capitalize all words that are

four letters long or greater within the title of a source: Permanence and Change.

Exceptions apply to short words that are verbs, nouns, pronouns, adjectives, and

adverbs: Writing New Media, There Is Nothing Left to Lose. (Note that in your

References list, only the first word of a title will be capitalized: Writing new


 When capitalizing titles, capitalize both words in a hyphenated compound word:

Natural-Born Cyborgs.

 Capitalize the first word after a dash or colon: “Defining Film Rhetoric: The Case

of Hitchcock’s Vertigo.”

 Italicize or underline the titles of longer works such as books, edited collections,

movies, television series, documentaries, or albums: The Closing of the American

Mind; The Wizard of Oz; Friends.

 Put quotation marks around the titles of shorter works such as journal articles,

articles from edited collections, television series episodes, and song titles:

“Multimedia Narration: Constructing Possible Worlds”; “The One Where

Chandler Can’t Cry.”

Short Quotations

If you are directly quoting from a work, you will need to include the author, year of

publication, and the page number for the reference (preceded by “p.”). Introduce the

quotation with a signal phrase that includes the author’s last name followed by the date of

publication in parentheses.

According to Jones (1998), “Students often had difficulty using APA style,

especially when it was their first time” (p. 199).

Jones (1998) found “students often had difficulty using APA style” (p. 199);

what implications does this have for teachers?

If the author is not named in a signal phrase, place the author’s last name, the year of

publication, and the page number in parentheses after the quotation.

She stated, “Students often had difficulty using APA style,” (Jones, 1998, p.

199), but she did not offer an explanation as to why.

Long Quotations

Place direct quotations longer than 40 words in a free-standing block of typewritten lines,

and omit quotation marks. Start the quotation on a new line, indented five spaces from

the left margin. Type the entire quotation on the new margin, and indent the first line of

any subsequent paragraph within the quotation five spaces from the new margin.

Maintain double-spacing throughout. The parenthetical citation should come after closing

punctuation mark.

Jones’s (1998) study found the following:

Students often had difficulty using APA style, especially when it was their

first time citing sources. This difficulty could be attributed to the fact that

many students failed to purchase a style manual or to ask their teacher for

help. (p. 199)

Summary or Paraphrase

If you are paraphrasing an idea from another work, you only have to make reference to

the author and year of publication in your in-text reference, but APA guidelines

encourage you to also provide the page number (although it is not required.)

According to Jones (1998), APA style is a difficult citation format for first-

time learners.

APA style is a difficult citation format for first-time learners (Jones, 1998,

p. 199).

In-Text Citations: Author/Authors

APA style has a series of important rules on using author names as part of the author-date

system. There are additional rules for citing indirect sources, electronic sources, and

sources without page numbers.

Citing an Author or Authors

A Work by Two Authors:Name both authors in the signal phrase or in the parentheses

each time you cite the work. Use the word “and” between the authors’ names within the

text and use “&” in the parentheses.

Research by Wegener and Petty (1994) showed…

(Wegener & Petty, 1994)

A Work by Three to Five Authors: List all the authors in the signal phrase or in

parentheses the first time you cite the source.

(Kernis, Cornell, Sun, Berry, & Harlow, 1993)

In subsequent citations, only use the first author’s last name followed by “et al.” in the

signal phrase or in parentheses.

(Kernis et al., 1993)

In et al., et should not be followed by a period.

Six or More Authors: Use the first author’s name followed by et al. in the signal phrase

or in parentheses.

Harris et al. (2001) argued…

(Harris et al., 2001)

Unknown Author: If the work does not have an author, cite the source by its title in the

signal phrase or use the first word or two in the parentheses. Titles of books and reports

are italicized or underlined; titles of articles and chapters are in quotation marks.

A similar study was done of students learning to format research papers (“Using

APA,” 2001).

Note: In the rare case the “Anonymous” is used for the author, treat it as the author’s

name (Anonymous, 2001). In the reference list, use the name Anonymous as the author.

Organization as an Author: If the author is an organization or a government agency,

mention the organization in the signal phrase or in the parenthetical citation the first time

you cite the source.

According to the American Psychological Association (2000),…

If the organization has a well-known abbreviation, include the abbreviation in brackets

the first time the source is cited and then use only the abbreviation in later citations.

First citation: (Mothers Against Drunk Driving [MADD], 2000)

Second citation: (MADD, 2000)

Two or More Works in the Same Parentheses: When your parenthetical citation

includes two or more works, order them the same way they appear in the reference list,

separated by a semi-colon.

(Berndt, 2002; Harlow, 1983)

Authors With the Same Last Name: To prevent confusion, use first initials with the last


(E. Johnson, 2001; L. Johnson, 1998)

Two or More Works by the Same Author in the Same Year: If you have two sources

by the same author in the same year, use lower-case letters (a, b, c) with the year to order

the entries in the reference list. Use the lower-case letters with the year in the in-text


Research by Berndt (1981a) illustrated that…

Personal Communication: For interviews, letters, e-mails, and other person-to-person

communication, cite the communicators name, the fact that it was personal

communication, and the date of the communication. Do not include personal

communication in the reference list.

(E. Robbins, personal communication, January 4, 2001).

A. P. Smith also claimed that many of her students had difficulties with APA

style (personal communication, November 3, 2002).

Citing Indirect Sources

If you use a source that was cited in another source, name the original source in your

signal phrase. List the secondary source in your reference list and include the secondary

source in the parentheses.

Johnson argued that…(as cited in Smith, 2003, p.102).

Note:When citing material in parentheses, set off the citation with a comma, as above.

Electronic Sources

If possible, cite an electronic document the same as any other document by using the

author-date style.

Kenneth (2000) explained…

Unknown Author and Unknown Date: If no author or date is given, use the title in your

signal phrase or the first word or two of the title in the parentheses and use the

abbreviation “n.d.” (for “no date”).

Another study of students and research decisions discovered that students

succeeded with tutoring (“Tutoring and APA,” n.d.).

Sources Without Page Numbers

When an electronic source lacks page numbers, you should try to include information that

will help readers find the passage being cited. When an electronic document has

numbered paragraphs, use the ¶ symbol, or the abbreviation “para.” followed by the

paragraph number (Hall, 2001, ¶ 5) or (Hall, 2001, para. 5). If the paragraphs are not

numbered and the document includes headings, provide the appropriate heading and

specify the paragraph under that heading. Note that in some electronic sources, like Web

pages, people can use the Find function in their browser to locate any passages you cite.

According to Smith (1997), … (Mind over Matter section, para. 6).

Note: Never use the page numbers of Web pages you print out; different computers print

Web pages with different pagination.

Reference List: Basic Rules

Your reference list should appear at the end of your paper. It provides the information

necessary for a reader to locate and retrieve any source you cite in the body of the paper.

Each source you cite in the paper must appear in your reference list; likewise, each entry

in the reference list must be cited in your text.

Your references should begin on a new page separate from the text of the essay; label this

page References (with no quotation marks, underlining, etc.), centered at the top of the

page. It should be double-spaced just like the rest of your essay.

Basic Rules

 All lines after the first line of each entry in your reference list should be indented

one-half inch from the left margin. This is called hanging indentation.

 Authors’ names are inverted (last name first); give the last name and initials for all

authors of a particular work unless the work has more than six authors. If the

work has more than six authors, list the first six authors and then use et al. after

the sixth author’s name to indicate the rest of the authors.

 Reference list entries should be alphabetized by the last name of the first author of

each work.

 If you have more than one article by the same author, single-author references or

multiple-author references with the exact same authors in the exact same order are

listed in order by the year of publication, starting with the earliest.

 When referring to any work that is NOT a journal, such as a book, article, or Web

page, capitalize only the first letter of the first word of a title and subtitle, the first

word after a colon or a dash in the title, and proper nouns. Do not capitalize the

first letter of the second word in a hyphenated compound word.

 Capitalize all major words in journal titles.

 Italicize titles of longer works such as books and journals.

 Do not italicize, underline, or put quotes around the titles of shorter works such as

journal articles or essays in edited collections.

Reference List: Author/Authors

The following rules for handling works by a single author or multiple authors apply to all

APA-style references in your reference list, regardless of the type of work (book, article,

electronic resource, etc.)

Single Author

Last name first, followed by author initials.

Berndt, T. J. (2002). Friendship quality and social development. Current Directions

in Psychological Science, 11, 7-10.

Two Authors

List by their last names and initials. Use the “&” instead of “and.”

Wegener, D. T., & Petty, R. E. (1994). Mood management across affective states: The

hedonic contingency hypothesis. Journal of Personality & Social Psychology, 66,


Three to Six Authors

List by last names and initials; commas separate author names, while the last author name

is preceded again by “&”

Kernis, M. H., Cornell, D. P., Sun, C. R., Berry, A., & Harlow, T. (1993). There’s

more to self-esteem than whether it is high or low: The importance of stability

of self-esteem. Journal of Personality and Social Psychology, 65, 1190-1204.

More Than Six Authors

If there are more than six authors, list the first six as above and then “et al.,” which stands

for “and others.” Remember not to place a period after “et” in “et al.”

Harris, M., Karper, E., Stacks, G., Hoffman, D., DeNiro, R., Cruz, P., et al.

(2001). Writing labs and the Hollywood connection. Journal of Film and Writing,

44(3), 213-245.

Organization as Author

American Psychological Association. (2003).

Unknown Author

Merriam-Webster’s collegiate dictionary (10th ed.).(1993). Springfield, MA:


NOTE: When your essay includes parenthetical citations of sources with no author

named, use a shortened version of the source’s title instead of an author’s name. Use

quotation marks and italics as appropriate. For example, parenthetical citations of the two

sources above would appear as follows: (Merriam-Webster’s, 1993) and (“New Drug,”


Two or More Works by the Same Author

Use the author’s name for all entries and list the entries by the year (earliest comes first).

Berndt, T.J. (1981).

Berndt, T.J. (1999).

When an author appears both as a sole author and, in another citation, as the first author

of a group, list the one-author entries first.

Berndt, T. J. (1999). Friends’ influence on students’ adjustment to school.

Educational Psychologist, 34, 15-28.

Berndt, T. J., & Keefe, K. (1995). Friends’ influence on adolescents’ adjustment to

school. Child Development, 66, 1312-1329.

References that have the same first author and different second and/or third authors are

arranged alphabetically by the last name of the second author, or the last name of the

third if the first and second authors are the same.

Wegener, D. T., Kerr, N. L., Fleming, M. A., & Petty, R. E. (2000). Flexible

corrections of juror judgments: Implications for jury instructions. Psychology,

Public Policy, & Law, 6, 629-654.

Wegener, D. T., Petty, R. E., & Klein, D. J. (1994). Effects of mood on high

elaboration attitude change: The mediating role of likelihood judgments.

European Journal of Social Psychology, 24, 25-43.

Two or More Works by the Same Author in the Same Year

If you are using more than one reference by the same author (or the same group of

authors listed in the same order) published in the same year, organize them in the

reference list alphabetically by the title of the article or chapter. Then assign letter

suffixes to the year. Refer to these sources in your essay as they appear in your reference

list, e.g.: “Berdnt (1981a) makes similar claims…”

Berndt, T. J. (1981a). Age changes and changes over time in prosocial intentions

and behavior between friends. Developmental Psychology, 17, 408-416.

Berndt, T. J. (1981b). Effects of friendship on prosocial intentions and

behavior. Child Development, 52, 636-643. Reference List: Articles in

Basic Form

APA style dictates that authors are named last name followed by initials; publication year

goes between parentheses, followed by a period. The title of the article is in sentence-

case, meaning only the first word and proper nouns in the title are capitalized. The

periodical title is run in title case, and is followed by the volume number which, with the

title, is also italicized or underlined.

Author, A. A., Author, B. B., & Author, C. C. (Year). Title of article. Title of

Periodical, volume number(issue number), pages.

Article in Journal Paginated by Volume

Journals that are paginated by volume begin with page one in issue one, and continue

numbering issue two where issue one ended, etc.

Harlow, H. F. (1983). Fundamentals for preparing psychology journal articles.

Journal of Comparative and Physiological Psychology, 55, 893-896.

Article in Journal Paginated by Issue

Journals paginated by issue begin with page one every issue; therefore, the issue number

gets indicated in parentheses after the volume. The parentheses and issue number are not

italicized or underlined.

Scruton, R. (1996). The eclipse of listening. The New Criterion, 15(30), 5-13.

Article in a Magazine

Henry, W. A., III. (1990, April 9). Making the grade in today’s schools. Time, 135,


Article in a Newspaper

Unlike other periodicals, p. or pp. precedes page numbers for a newspaper reference in

APA style. Single pages take p., e.g., p. B2; multiple pages take pp., e.g., pp. B2, B4 or

pp. C1, C3-C4.

Schultz, S. (2005, December 28). Calls made to strengthen state energy policies.

The Country Today, pp. 1A, 2A.

Letter to the Editor

Moller, G. (2002, August). Ripples versus rumbles [Letter to the editor].

Scientific American, 287(2), 12.


Baumeister, R. F. (1993). Exposing the self-knowledge myth [Review of the book The

self-knower: A hero under control ]. Contemporary Psychology, 38, 466-467.

Reference List: Books

Basic Format for Books

Author, A. A. (Year of publication). Title of work: Capital letter also for

subtitle. Location: Publisher.

NOTE: For “Location,” you should always list the city, but you should also include the

state if the city is unfamiliar or if the city could be confused with one in another state.

Calfee, R. C., & Valencia, R. R. (1991). APA guide to preparing manuscripts for

journal publication. Washington, DC: American Psychological Association.

Edited Book, No Author

Duncan, G.J., & Brooks-Gunn, J. (Eds.). (1997). Consequences of growing up poor.

New York: Russell Sage Foundation.

Edited Book with an Author or Authors

Plath, S. (2000). The unabridged journals (K.V. Kukil, Ed.). New York: Anchor.

A Translation

Laplace, P. S. (1951). A philosophical essay on probabilities. (F. W. Truscott & F.

L. Emory, Trans.). New York: Dover. (Original work published 1814).

NOTE: When you cite a republished work, like the one above, work in your text, it

should appear with both dates: Laplace (1814/1951).

Edition Other Than the First

Helfer, M.E., Keme, R.S., & Drugman, R.D. (1997). The battered child (5th ed.).

Chicago: University of Chicago Press.

Article or Chapter in an Edited Book

Author, A. A., & Author, B. B. (Year of publication). Title of chapter. In A.

Editor & B. Editor (Eds.), Title of book (pages of chapter). Location:


NOTE: When you list the pages of the chapter or essay in parentheses after the book

title, use “pp.” before the numbers: (pp. 1-21). This abbreviation, however, does not

appear before the page numbers in periodical references, except for newspapers.

O’Neil, J. M., & Egan, J. (1992). Men’s and women’s gender role journeys: Metaphor

for healing, transition, and transformation. In B. R. Wainrib (Ed.), Gender

issues across the life cycle (pp. 107-123). New York: Springer.

Multivolume Work

Wiener, P. (Ed.). (1973). Dictionary of the history of ideas (Vols. 1-4). New York:


Reference List: Electronic Sources

Article From an Online Periodical

Online articles follow the same guidelines for printed articles. Include all information the

online host makes available, including an issue number in parentheses.

Author, A. A., & Author, B. B. (Date of publication). Title of article. Title of

Online Periodical, volume number(issue number if available). Retrieved month

day, year, from http://www.someaddress.com/full/url/

Bernstein, M. (2002). 10 tips on writing the living Web. A List Apart: For People

Who Make Websites, 149. Retrieved May 2, 2006, from


Online Scholarly Journal Article

Author, A. A., & Author, B. B. (Date of publication). Title of article. Title of

Journal, volume number. Retrieved month day, year, from


Kenneth, I. A. (2000). A Buddhist response to the nature of human rights. Journal of

Buddhist Ethics, 8.Retrieved February 20, 2001, from


If the article appears as a printed version as well, the URL is not required. Use

“Electronic version” in brackets after the article’s title.

Whitmeyer, J.M. (2000). Power through appointment [Electronic version]. Social

Science Research, 29, 535-555.

Article From a Database

When referencing material obtained from an online database (such as a database in the

library), provide appropriate print citation information (formatted just like a “normal”

print citation would be for that type of work). Then add information that gives the date of

retrieval and the proper name of the database. This will allow people to retrieve the print

version if they do not have access to the database from which you retrieved the article.

You can also include the item number or accession number in parentheses at the end, but

the APA manual says that this is not required. (For more about citing articles retrieved

from electronic databases, see page 278 of the Publication Manual.)

Smyth, A. M., Parker, A. L., & Pease, D. L. (2002). A study of enjoyment of peas.

Journal of Abnormal Eating, 8(3). Retrieved February 20, 2003, from

PsycARTICLES database.

Nonperiodical Web Document, Web Page, or Report

List as much of the following information as possible (you sometimes have to hunt

around to find the information; don’t be lazy. If there is a page like

http://www.somesite.com/somepage.htm, and somepage.htm doesn’t have the information

you’re looking for, move up the URL to http://www.somesite.com/):

Author, A. A., & Author, B. B. (Date of publication). Title of document. Retrieved

month day, year, from http://Web address.

NOTE: When an Internet document is more than one Web page, provide a URL that

links to the home page or entry page for the document. Also, if there isn’t a date available

for the document use (n.d.) for no date.

Chapter or Section of a Web document

Author, A. A., & Author, B. B. (Date of publication). Title of article. In Title of

book or larger document (chapter or section number). Retrieved month day, year,

from http://www.someaddress.com/full/url/.

Engelshcall, R. S. (1997). Module mod_rewrite: URL Rewriting Engine. In Apache HTTP

Server Version 1.3 Documentation (Apache modules.) Retrieved March 10, 2006,


This resource was written by Stacy Weida for OWL Purdue

Starting the Writing Process

Writing takes time

Find out when is the assignment due and devise a plan of action. This may seem obvious and

irrelevant to the writing process, but it’s not. Writing is a process, not merely a product. Even the best

professional writers don’t just sit down at a computer, write, and call it a day. The quality of your

writing will reflect the time and forethought you put into the assignment. Plan ahead for the

assignment by doing pre-writing: this will allow you to be more productive and organized when you sit

down to write. Also, schedule several blocks of time to devote to your writing; then, you can walk

away from it for a while and come back later to make changes and revisions with a fresh mind.

Use the rhetorical elements as a guide to think through your

Thinking about your assignment in terms of the rhetorical situation can help guide you in the

beginning of the writing process. Topic, audience, genre, style, opportunity, research, the writer, and

purpose are just a few elements that make up the rhetorical situation.

Topic and audience are often very intertwined and work to inform each other. Start with a broad view

of your topic such as skateboarding, pollution, or the novel Jane Eyre and then try to focus or refine

your topic into a concise thesis statement by thinking about your audience. Here are some questions

you can ask yourself about audience:

 Who is the audience for your writing?

 Do you think your audience is interested in the topic? Why or why not?

 Why should your audience be interested in this topic?

 What does your audience already know about this topic?

 What does your audience need to know about this topic?

 What experiences has your audience had that would influence them on this topic?

 What do you hope the audience will gain from your text?

For example, imagine that your broad topic is dorm food. Who is your audience? You could be writing

to current students, prospective students, parents of students, university administrators, or nutrition

experts among others. Each of these groups would have different experiences with and interests in the

topic of dorm food. While students might be more concerned with the taste of the food or the hours

food is available parents might be more concerned with the price.

You can also think about opportunity as a way to refine or focus your topic by asking yourself what

current events make your topic relevant at this moment. For example, you could connect the

nutritional value of dorm food to the current debate about the obesity epidemic or you could connect

the price value of dorm food to the rising cost of a college education overall.

Keep in mind the purpose of the writing assignment.

Writing can have many different purposes. Here are just a few examples:

 Summarizing: Presenting the main points or essence of another text in a condensed form

 Arguing/Persuading: Expressing a viewpoint on an issue or topic in an effort to convince

others that your viewpoint is correct

 Narrating: Telling a story or giving an account of events

 Evaluating: Examining something in order to determine its value or worth based on a set of


 Analyzing: Breaking a topic down into its component parts in order to examine the

relationships between the parts.

 Responding: Writing that is in a direct dialogue with another text.

 Examining/Investigating: Systematically questioning a topic to discover or uncover facts that

are not widely known or accepted, in a way that strives to be as neutral and objective as


 Observing: Helping the reader see and understand a person, place, object, image or event

that you have directly watched or experienced through detailed sensory descriptions.

You could be observing your dorm cafeteria to see what types of food students are actually eating,

you could be evaluating the quality of the food based on freshness and quantity, or you could be

narrating a story about how you gained fifteen pounds your first year at college.

You may need to use several of these writing strategies within your paper. For example you could

summarize federal nutrition guidelines, evaluate whether the food being served at the dorm fits those

guidelines, and then argue that changes should be made in the menus to better fit those guidelines.

Pre-writing strategies

Once you have thesis statement just start writing! Don’t feel constrained by format issues. Don’t

worry about spelling, grammar, or writing in complete sentences. Brainstorm and write down

everything you can think of that might relate to the thesis and then reread and evaluate the ideas you

generated. It’s easier to cut out bad ideas than to only think of good ones. Once you have a handful of

useful ways to approach thesis you can use a basic outline structure to begin to think about

organization. Remember to be flexible; this is just a way to get you writing. If better ideas occur to

you as you’re writing, don’t be afraid to refine your original ideas.

Symptoms and Cures for Writer’s Block

Because writers have various ways of writing, a variety of things can cause a writer to experience

anxiety, and sometimes this anxiety leads to writer’s block. Often a solution can be found by speaking

with your instructor (if you are in school), or a writing tutor. There are some common causes of

writer’s block, however, and when you are blocked, consider these causes and try the strategies that

sound most promising:


You have attempted to begin a paper without doing any preliminary work such as brainstorming or


Possible Cures

 Use invention strategies suggested by a tutor or teacher

 Write down all the primary ideas you’d like to express and then fill in each with the smaller

ideas that make up each primary idea. This can easily be converted into an outline


You have chosen or been assigned a topic which bores you….

Possible Cures

 Choose a particular aspect of the topic you are interested in (if the writing situation will allow

it…i.e. if the goal of your writing can be adjusted and is not given to you specifically, or if the

teacher or project coordinator will allow it)

 Talk to a tutor about how you can personalize a topic to make it more interesting


You don’t want to spend time writing or don’t understand the assignment…

Possible Cures

 Resign yourself to the fact that you have to write

 Find out what is expected of you (consult a teacher, textbook, student, tutor, or project


 Look at some of the strategies for writing anxiety listed below


You are anxious about writing the paper…

Possible Cures

 Focus your energy by rehearsing the task in your head.

 Consciously stop the non-productive comments running through your head by replacing them

with productive ones.

 If you have some “rituals” for writing success (chewing gum, listening to jazz etc.), use them.


You are so stressed out you can’t seem to put a word on the page…

Possible Cures

 Stretch! If you can’t stand up, stretch as many muscle groups as possible while staying


 Try tensing and releasing various muscle groups. Starting from your toes, tense up for

perhaps five to ten seconds and then let go. Relax and then go on to another muscle group.

 Breathe deeply. Close your eyes; then, fill your chest cavity slowly by taking four of five short

deep breaths. Hold each breath until it hurts, and then let it out slowly.

 Use a calming word or mental image to focus on while relaxing. If you choose a word, be

careful not to use an imperative. Don’t command yourself to “Calm down!” or “Relax!”


You’re self-conscious about your writing, you may have trouble getting started. So, if you’re

preoccupied with the idea that you have to write about a subject and feel you probably won’t express

yourself well…

Possible Cures

 Talk over the subject with a friend or tutor.

 assure yourself that the first draft doesn’t have to be a work of genius, it is something to work


 Force yourself to write down something, however poorly worded, that approximates your

thought (you can revise this later) and go on with the next idea.

 Break the task up into steps. Meet the general purpose first, and then flesh out the more

specific aspects later.

 Try one of the strategies on the next page of this resource.

Other Strategies for Getting Over Writer’s Block

If you have tried the other strategies and are still having problems, try some of these general

techniques for getting over writer’s block. These strategies will prove more helpful when you’re

drafting your writing.

Begin in the Middle

Start writing at whatever point you like. If you want to begin in the middle, fine. Leave the

introduction or first section until later. The reader will never know that you wrote the paper

“backwards.” Besides, some writers routinely save the introduction until later when they have a

clearer idea of what the main idea and purpose of the piece will be.

Talk Out the Paper

Talking feels less artificial than writing to some people. Talk about what you want to write someone—

your teacher, a friend, a roommate, or a tutor. Just pick someone who’s willing to give you fifteen to

thirty minutes to talk about the topic and whose main aim is to help you start writing. Have the

person take notes while you talk or tape your conversation. Talking will be helpful because you’ll

probably be more natural and spontaneous in speech than in writing. Your listener can ask questions

and guide you as you speak, and you’ll be more likely to relax and say something unpredictable than if

that you were sitting and forcing yourself to write.

Tape the Paper

Talk into a tape recorder, imagining your audience sitting in front of you. Then, transcribe the tape-

recorded material. You’ll at least have some ideas written down to work with and move around.

Change the Audience

Pretend that you’re writing to a child, to a close friend, to a parent, to a person who sharply disagrees

with you, or to someone who’s new to the subject and needs to have you explain your paper’s topic

slowly and clearly. Changing the audience can clarify your purpose and can also make you feel more

comfortable and help you write more easily.

Play a Role

Pretend you are someone else writing the paper. For instance, if you have been asked to write about

sexist advertising, assume you are the president of the National Organization of Women. Or, pretend

you are the president of a major oil company asked to defend the high price of oil. Consider being

someone in another time period, or someone with a wildly different perspective from your own. Pulling

yourself out of your usual perspective can help you see things that are otherwise invisible or difficult

to articulate, and your writing will be stronger for it.

(Many of these ideas are from Peter Elbow’s Writing with Power, [Ch. 8; 59-77] and Mack Skjei’s

Overcoming Writing Blocks.)



Taeho Kim
This draft: May 5, 2021


Controversial police use-of-force incidents have eroded police legitimacy, and body-
worn cameras (BWCs) have received extensive attention as a key reform. I study the
causal effects of BWCs on the use of force and law enforcement outcomes. Previous
studies that randomized BWC deployment at the officer level within a single agency
faced empirical challenges as (1) the control group officers are also indirectly affected by
BWCs due to interactions with the treatment group officers (spillover), (2) there may
be fundamental differences between agencies that agree to be researched and agencies
that do not (site-selection bias), and (3) researchers could not directly examine agency-
wide variables such as crime rates and public opinion. I overcome these limitations
by conducting the first nationwide study of BWCs across more than 1,000 agencies
in the US. I find that BWCs lead to substantial decreases in the use of force, both
against whites and minorities. Nationwide, they reduce police-involved homicides by
58%. In contrast to previous studies on police accountability, I find no evidence of an
association between police oversight through BWCs and reduction in policing efforts.
By examining social media usage from Twitter, I find that BWC adoption has improved
public opinion toward the police. These findings imply that BWCs can be an important
tool for improving police accountability without sacrificing policing capabilities.
JEL: K40, H40, M50

∗The University of Chicago, The Kenneth C. Griffin Department of Economics; 111 W Maple St, Apt
1310, Chicago, IL, 60610; 312 723 8137; [email protected] I would like to thank Steve Levitt, Michael
Greenstone, Heather Sarsons, and Alessandra Voena for their guidance and helpful discussion. I am grate-
ful to William McCarty for familiarizing me with the BWC literature, and officers at the Chicago Police
Department and Schaumburg Police Department, IL, for providing me with institutional background. I
thank Stephane Bonhomme, Joshua Dean, Manasi Deshpande, Alex Frankel, Alex Imas, Jacob Leshno,
Magne Mogstad, Jack Mountjoy, Derek Neal, Matthew Notowidigdo, Canice Prendergast, Alex Torgovitsky,
Thomas Wollmann, and seminar participants at UChicago for their helpful feedback.


Electronic copy available at: https://ssrn.com/abstract=3474634


Recent high-profile and controversial police use-of-force incidents have spurred protests

across the nation and calls for police reform. In ensuing debates, officer body-worn cameras

(BWCs) have been examined as a key to police reform by providing video documentation of

police encounters with community members. BWCs have the potential to significantly affect

policing by strengthening accountability and promoting community relations.

However, the question of whether BWCs are a viable solution to the police legitimacy

crisis is far from settled. BWCs may lead to reduction in policing efforts as officers become

more afraid of making errors and become less proactive in crime control activities. Moreover,

BWCs may not lead to reduction in the use of force if there is no margin of improvement in

current police practices or police unions are so powerful that officers who are found to have

used excessive force through BWCs do not face real consequences.

In this paper, I study the causal effects of BWCs on the use of force, enforcement out-

comes, and public opinion toward the police in the first nationwide study of over 1,000 local

police agencies in the US. I examine the staggered adoption of BWCs in a quasi-experimental

difference-in-difference (DID) approach. My empirical method relies on the idiosyncratic tim-

ing of BWC adoption that are attributable to administrative hurdles in the adoption process.

Anecdotal evidence suggests that as agencies rushed to adopt BWCs starting in 2014, they

faced bureaucratic delays in implementation that stemmed from uncertainties about funding

and BWC policies. Consistent with this, I find that while there are fundamental differences

between agencies that do and do not adopt BWCs, among adopters of BWCs, characteristics

of police agencies are not related to when they adopted BWCs. While selection into BWC

adoption may be endogenous, a key assumption of this approach is that the timing of BWC

adoption is uncorrelated with other determinants of changes in the use of force.

To leverage the variations in adoption timing, I gather data on agency-level use of


Electronic copy available at: https://ssrn.com/abstract=3474634

force as well as data on BWC adoption. My data on BWC adoption status come from the

Body Worn Camera Supplement to the Law Enforcement Management and Administrative

Statistics (LEMAS) Survey, a novel survey by the Bureau of Justice Statistics that asks police

chiefs in the US if they have adopted BWCs, and if so, in which year and what month. At

the national level, I gather data on police-involved homicides from 2013 to 2019. I aggregate

the incident-level observations at the agency-month level and merge them with time-varying

adoption status.

In my national analysis on police-involved homicides, I find that BWCs contribute to

substantial reductions (58%) in these incidents in an immediate trend break after BWC

adoption. When I further disaggregate these results according to the races of the victims, I

find that this decrease can be attributed to both white and minority populations. Previous

studies have largely neglected disaggregated analysis of the use of force by race. However,

this finding is especially relevant given the recent controversy surrounding police use-of-force

incidents, in which the victims tend to be minorities.

I use several strategies to rule out alternative explanations for the reduction of the

use of force. First, I use high-frequency monthly data to isolate BWC adoption from other

concurrent policies that may have been adopted together. As it typically takes about 18

months to implement BWCs, the monthly data allows me to observe the time trends of

police-involved homicides near the month of adoption at a granular level. Other confounding

reforms such as training and changes in use-of-force policies are unlikely to generate the

trend break in the use of force immediately following adoption because they do not involve

bureaucratic processes that are necessary for BWC implementation and thus would not have

implementation schedules that precisely overlap with that of BWCs. Second, I more directly

test whether BWC adoption coincided with other interventions, I gather data on purchase

orders of police training. Additionally, I analyze the possibility that agencies with high

logistical capacities can quickly implement BWC programs as an immediate response to a


Electronic copy available at: https://ssrn.com/abstract=3474634

scandal. I run robustness checks excluding agencies that indicated they did not face obstacles

to implementation and find that the results are not driven by such agencies.

To shed light on possible explanations for the reduction in the use-of-force incidents,

I consider three factors which I describe in a model of police behavior: disengagement by

police, improved police tactics, and improved citizen behavior. I find that an explanation

based on improved police tactics is most consistent with my empirical results. To check

whether disengagement has driven the reduction in the use of force, I test whether BWCs

have led to decreases in arrests or changes in crime rates; I do not find evidence for either.

This result is surprising given that previous studies on police oversight have found that

public scrutiny on the police can lead to severe police disengagement (Prendergast, 2001,

Shi, 2009, and Devi and Fryer Jr., 2020). Improved citizen behavior is also unlikely to drive

the reduction in the use of force as I do not find that BWCs have led to measurable changes

in assaults on the police. On the other hand, an explanation based on improved police

tactics is most consistent with my empirical results. Finally, I investigate whether BWCs

have reduced the use of force by improving police tactics using the LEMAS survey of police

chiefs which directly asks about the ways in which BWCs have been useful. I find that

the majority of police chiefs who have adopted BWCs agree that BWCs help improve the

professionalism of the officers and BWCs help facilitate officer training. In accordance with

their answers, I find that agencies that agreed that BWCs pose these benefits experience

greater reductions in the use of force than those that do not.

I also explore if BWCs have also led to changes in the use of force less severe than

deadly force, by supplementing my national analysis with an analysis of lower-level use of

force in New Jersey. I gather administrative data on all use of force in New Jersey from 2012

to 2016. I find that in New Jersey, implementation of BWCs has decreased the total use of

force by 20% and subject injuries by 42% following the implementation of BWCs.

Public perceptions are an important measure of police performance. Distrust in the


Electronic copy available at: https://ssrn.com/abstract=3474634

police can interfere with proper crime control and lead to rises in crime levels. However,

it is difficult to measure changes in public opinion using conventional data sources such as

surveys because they do not capture high-frequency variations over wide geographic regions.

I overcome this issue by gathering police-related tweets on Twitter. Using these data sources,

I find that BWCs lead to improved sentiments on Twitter. After BWC adoption, total tweets

about police drop by 21% and I gather suggestive evidence that sentiments also improve.

In the final section of my analysis, I interpret the reductions in the use of force in the

context of social welfare. Using a monetized value of averted police-involved homicides and

my estimates, I find that BWC programs lead to an increase in social welfare.

My national study on BWCs overcomes limitations in previous studies that have eval-

uated BWCs in single-agency settings by randomizing the treatment of equipping BWCs at

the officer level in the same agency (Ariel, 2016; Braga, Sousa, et al., 2018; Jennings et al.,

2015; Yokum et al., 2019). While this research has revealed a wealth of information about

various aspects of BWCs, the single-agency research design presents several shortcomings.

For instance, this study design does not adequately account for spillover effects on control

group officers who are also indirectly affected by working closely with treatment group of-

ficers. Moreover, these studies only examine agencies willing to cooperate with researchers,

and as such, it may be difficult to generalize from them due to site-selection bias. Also, my

cross-agency analysis allows me to study agency-wide performance measures such as crime

rates and public attitudes that single-agency studies cannot adequately examine.

In addition to contributing to current research on BWCs, which I explore in Section

II.C, I make several contributions to existing literature. First, this paper contributes to the

literature on the effects of police inputs on crime outcomes. Most of this literature focuses on

measuring the impacts of hiring more police officers (Levitt, 1997; McCrary, 2007; Miller and

Segal, 2019; Mello, 2019). Recent papers, however, evaluated innovations in policing, such

as the use of computerization (Garicano and Heaton, 2010) and DNA databases (Doleac,


Electronic copy available at: https://ssrn.com/abstract=3474634

2017). By studying an input that has been introduced primarily to decrease the use of force

and “side-effects” from policing, this paper differs from previous research on inputs applied

to improve general crime rates and clearance rates.

Additionally, this paper contributes to the recent literature that has analyzed on police

use of force as well as civilian complaints. Fryer Jr. (2018) explores racial differences in

the police use of force, while Ba (2017) and Rivera and Ba (2019) study the interactions

between civilian oversight and the use of force and complaints. Annan-Phan and Ba (2019)

examine the effects of the patrol environment on deadly force. Rozema and Schanzenbach

(2019) study intervention methods that can predict which officers will display the most

civilian allegations of misconduct. This paper differs from these papers by evaluating an

accountability tool that could help reduce the use of force and complaints.

More broadly, this paper contributes to a large body of literature on agency issues in

the public sector. It is more difficult to incentivize government bureaucrats than private

sector employees because it is hard to find an objective measure of performance and the set

of contracts governments can offer their employees is limited (Finan et al., 2017). Among dif-

ferent types of government agencies, enforcement agencies face particularly severe challenges

because of multitasking problems (Khan et al., 2016, Prendergast, 2001, Shi, 2009, Ba, 2017,

Rivera and Ba, 2019, Devi and Fryer Jr., 2020). This paper provides one of the first evidence

that suggests an accountability tool could bring benefits in enforcement agencies.

Finally, this paper relates to the literature that examines technology adoption, work

organization, and performance (e.g., Bresnahan et al., 2002; Hubbard, 2003; Athey and

Stern, 2002; Acemoglu et al., 2007; Aral et al., 2007). Although organizations have invested

substantially in monitoring employees, employee-monitoring technologies have been under-

studied in the literature. Such technologies have the potential to curb misconducts while

invasion of privacy can also have negative consequences for productivity or retention (Bern-

stein, 2012). Pierce et al. (2015) finds that a theft-monitoring software significantly reduced


Electronic copy available at: https://ssrn.com/abstract=3474634

theft and improved productivity in restaurants. I extend this literature by analyzing a video

recording technology that can more comprehensively capture employee behavior but is more

intrusive. My agency-level analysis allows me to study multiple dimensions of performance

in addition to undesirable behavior.

The remainder of the paper proceeds as follows. In Section II, I provide institutional

details about BWCs and present a stylized model of police behavior and BWCs. I also

describe previous studies on BWCs. Section III describes my data on BWC adoption status,

the use of force, and other performance measures. Section IV compares the characteristics

of agencies that adopt BWCs and those that do not, in addition to laying out an empirical

strategy for overcoming obstacles to the comparison of these two groups of agencies. In

Section V, I present my main results on the use of force and enforcement outcomes. I also

explore possible mechanisms underlying reductions in the use of force. Section VI analyzes

changes in public attitudes toward police after BWC adoption. In Section VII, I perform

a social welfare calculation of BWC programs and a budgetary analysis of BWC programs

from the perspective of police agencies. I conclude in Section VIII.



II.A Adoption of BWCs and Policies

Widespread public support and buy-ins from law enforcement executives and officers

have materialized into policy changes across the nation. In 2014, the Obama administration

proposed a subsidy of $263 million for the purchase of 50,000 BWCs by local law enforcement

agencies. Backed by an infusion of these federal funds, and reinforced by grants from state

and local governments, BWCs are now widely used in the US. Specifically, as of 2016, they

have been fully deployed by 60% of local police departments and 49% of sheriffs’ offices in


Electronic copy available at: https://ssrn.com/abstract=3474634

the US (Hyland, 2018). Currently, debates are active nationwide about whether to equip all

US law enforcement officers with BWCs.

BWCs are not a new technology, although they have evolved over time through the

incorporation of recent smart technological advances. BWCs have been tested in the United

Kingdom as early as 2005 (Harris, 2010). However, they did not gain widespread adoption

in the US until a string of high-profile and controversial officer-involved killings in New York,

Missouri, Illinois, and Ohio spurred public demand in the second half of 2014 (Maskaly et

al., 2017). Figure I depicts the evolution of the coverage of BWC programs across the US.

After a modest rise in BWC implementation in the US to around 15% of all agencies, BWC

adoption escalated in 2014 at a steeper rate, entering 67% of all agencies by June 2016. This

trend captures agencies’ haste to outfit officers in order to avoid controversies. Before BWCs

became the subject of public attention, agencies that adopted the technology had generally

deployed the devices to specialized positions such as traffic details or officers covering major

events such as protests and sporting events (Police Executive Research Forum, 2017).

From the perspective of police departments that were looking to obtain BWCs, BWCs

are more than just a device. First, they are expensive. BWC programming involves rigorous

logistics, vast data management systems, public records requests processing systems in ad-

dition to the cameras themselves. For example, Federal Ways, CA, that has 134 officers has

allocated for its BWC program $1.1 million for the initial year and $450K per year, which

represents 1.4% of the total annual budget and 3.8% of the budget for Field Operations. A

survey of US police executives, which serves as one of my primary data sources, shows that

the costs of BWC implementation are a real concern. 86% of executives that did not adopt

BWCs said that costs were a primary reason; this was followed by the burden of public

records request, which were mentioned by 70% of executives. Among agencies that adopted

BWCs, the biggest obstacle they faced in implementation was the fact that costs were higher

than anticipated, as reported in Table II. Because of the high expenses, agencies looking to


Electronic copy available at: https://ssrn.com/abstract=3474634

purchase BWCs resorted to funding opportunities provided by local, state or federal gov-

ernments. Second, the implementation of BWCs requires careful crafting of policies and

negotiations as BWCs carry sensitive information. Officers are sensitive to materials that is

recorded, stored, and released, because BWCs can intrude on their privacy and negatively

affect their employment status.

As a recording device that is more mobile than previous technologies such as car dash-

board cameras, the BWC has the potential to reshape police-citizen interactions. BWCs

can be worn on the front of officers’ uniforms or clipped to headgear. Different departments

have varying policies on what events to record. In my data sample, the majority of police

departments that adopted BWCs require officers to turn on BWCs during routine calls for

service, traffic stops, officer-initiated citizen contacts, firearms deployments, and executions

of arrests and search warrants. A common “fail-safe” feature of BWCs allows them to always

be on and save the 30 seconds of footage prior to the officer activating the record button.

Once the footage is recorded, it is usually stored with security protections to address

concerns of privacy and evidence integrity. Most agencies record and track internal access

to video files. The video files are kept in storage for varying periods of time, with the modal

response in my data being one month to a year. The videos may be kept for longer periods

of time if, for example, they are associated with use of force, a citizen complaints, or legal


The process of implementing BWCs is lengthy and contains many administrative hur-

dles. This paper’s identification strategy relies on the bureaucratic process that has prevented

agencies from maintaining full control over the timing of eventual adoption. The implemen-

tation process begins when the police chief consults with the local council and recommends

capital purchase. These two entities make decisions based on the positions of the public and


Electronic copy available at: https://ssrn.com/abstract=3474634

officers. The process takes about 18 months.1 The agency must study devices and requests

proposals from vendors. Because the BWC program is expensive, the agency prepares a

budget according to its availability and writes grants which often contain stipulations that

the award can only be used for cameras that have yet to be purchased. The agency must also

develop policies that satisfy the requests of the council as well as police unions, which may

prolong the process. Finally, the agency must train officers and install necessary hardwares

and hire personnel to process public records requests.

In the initial years of BWCs, as agencies navigated these bureaucratic processes, anec-

dotal evidence abounds that agencies faced long and arbitrary delays. For example, in

Nashville, TN, BWC was named a top priority in 2016 by city and police leadership, but in

2019, months before roll-out, the mayor delayed the program citing simmering budget crisis

and concerns over massive downstream costs. Agencies also awaited official policies from

county and state governments regarding BWC use and data release policies before imple-

menting their programs. These bureaucratic factors will serve as the basis for my empirical

design that relies on variation in BWC adoption timing.

II.B Model of Police Behavior and BWCs

How do BWCs change the use of force? First, as officers recognize that their actions

may be subject to closer scrutiny and that bad policing tactics are more likely to be detected

and punished, they consequently attempt to reduce actions that lead to bad behavior. Thus,

the total amount of policing efforts may decline, as bad policing may be proportional to

1A recent Chicago Tribune article (09/11/2020) quotes the Chief of Naperville, IL, police who made
the assessment based on other police departments’ timelines (https://www.chicagotribune.com/sub-


Electronic copy available at: https://ssrn.com/abstract=3474634

the total policing efforts. This phenomenon is commonly known as de-policing and has

been widely documented (Prendergast, 2001, Shi, 2009, Devi and Fryer Jr., 2020). Second,

BWCs may lead officers to develop more prudent police tactics by investing in their skills.

In addition, BWCs may further facilitate training by providing objective views into policing

in action. Anecdotal evidence suggests that agencies use footage from BWCs to provide

scenario-based training, to evaluate the performance of new officers in the field, and to

identify areas in which further training may be needed (Police Executive Research Forum,

2014). Third, citizens may be more likely to cooperate with police if they hold more positive

beliefs about the police who are equipped with BWCs or are aware that they are more likely

to be prosecuted for resisting arrest with video evidence.

To illustrate these concepts more clearly, I have constructed a model of police decision-

making based on the principal-agent models of policing in Prendergast (2001) and Shi (2009).

The objectives of the city (the principal) are to minimize crime while also minimizing errors

and expenditure. Police officers and their field supervisors (agents) decide upon the amount

of training and policing efforts facing the ex-post oversight. In the first stage, the agent

makes the decision of improving her force mitigation tactics such as tactical positioning,

verbal de-escalation techniques, and implicit bias controls. Through the principal-agent

model, bad policing naturally arises as a fixed proportion of policing efforts, and investment

in policing tactics reduces chances that bad policing will occur. These investments are costly

as they require close examination of current practices and efforts to detect and correct any

suboptimal behavior. BWCs may affect policing in the model in three different ways; they

may increase the rate of investigation of bad policing, reduce the cost of skill development,

or decrease hostility of citizens toward the police.

In the first stage of the model, the agent’s problem can be written as

U1 = max

w + δU2(k) − ck, (1)


Electronic copy available at: https://ssrn.com/abstract=3474634

where she maximizes the first period utility U1 by choosing k ∈ {0, 1}. If she chooses to

invest, she pays the cost c. She receives a fixed wage w from the principal and cares about

discounted future U2, which depends on her investment decision. In the second stage, she

decides the effort level in making arrests taking into account the expected penalty from errors

in arrests, rewards from arrests, and dis-utility from the effort:

U2 = max

{w − N(e) × ρh × q(k) × ρi × ∆ + f(N(e)) −

e2}, (2)

where N is the number of arrests made by the officer (which increases in effort e), ρh is

the citizen hostility parameter drawn i.i.d. from a distribution between 0 and 1 (where a

higher outcome implies more investigative cases), q(k) is the expected error rate which is a

decreasing function of skill investment from the first period, ρi is the rate of investigation

and finding that the officer is guilty of wrongdoing, ∆ is the punishment for being found

guilty. f(N(e)) represents the reward the principal gives to the agent for each arrest, and

the final term parametrizes the cost of arrest efforts.

The amount of the use of force F is increasing in arrest efforts e, decreasing in force

mitigation techniques k, and increasing in citizen hostility:

F =

eαρ1−αh , A > 1. (3)


In the model, the primitive variables that are directly affected by BWCs are ρi, c, and

ρh; BWC adoption increases ρi, and ρh, and decreases c. Through these changes, BWCs

may change the use of force in the following three channels:

1. BWCs decrease arrest efforts as greater ρi implies higher costs from police errors.

Lower arrest efforts lead to lower levels of use of force in Equation 3.


Electronic copy available at: https://ssrn.com/abstract=3474634

2. BWCs increase investment in policing skills as greater ρi incentives skill development to

reduce errors and cost of investment c decreases. The agent employs a cutoff strategy

when choosing to invest, in which lower costs of skill investment and higher rates of

investigation lead to decision to invest in skill development. Better skills directly lead

to less use of force2

3. As BWCs increase police legitimacy, lower ρh directly reduces the use of force. The

model mechanically generates this relationship in Equation 3.

The three channels have a few implications about law enforcement outcomes, which I

will use to guide my empirical findings. The first channel of lower policing efforts imply that

BWCs would also lead to lower arrests. The second channel implies increase in arrest rates,

as lower error rates from higher skills incentives greater policing efforts. The third channel

of lower citizen hostility implies lower assaults against officers. I use these predictions to

guide my analysis when I examine mechanisms behind changes in the use of force.

Not modeled here are potentially beneficial effects of BWCs on investigation and pros-

ecution, which may lead to reduction in cost of arrest efforts. However, since these aspects

are not primary factors that determine the use of force, I do not consider them in my model.

2Change in the use of force from skill development can be thought of as a combination of the direct effect
and the indirect effect through increased policing efforts (lower error rates lead officers to increase efforts).
In a model with continuous skill development k, the change in the use of force can be expressed as the total
derivative dF

, which equals






. (4)

With the added assumption that the direct effects of mitigation skills dominates the indirect effects through
increased arrest efforts, use of force declines.


Electronic copy available at: https://ssrn.com/abstract=3474634

II.C Previous Studies of BWCs

The gradually increasing body of academic research of BWCs, all in the field of crim-

inology, has lagged behind the rapid growth of interest in and adoption of the technology

and has sought to uncover whether BWCs fulfill promises of greater police accountability,

police efficacy, improved relations with the public (Lum et al., 2019). A significant number

of those studies have used a deterrence framework to examine the impacts of BWCs on offi-

cer behavior, including use of force (Ariel, 2016; Braga, Sousa, et al., 2018; Jennings et al.,

2015; Yokum et al., 2019), as well as citizen complaints about officer behavior or conduct

(Hedberg et al., 2017; Peterson et al., 2018), and arrests (Ariel, 2016; Ready and Young,


Table I lists randomized controlled trials that examine the effects of BWCs on use of

force listed in a recent literature …

This is a research paper; a review of the

Scientific literature. This is not an essay assignment. Research Paper

Is divided into four parts. Each paper will build on the previous paper. The paper will

Focus on The Effect of Body Cameras on Police Use of Force

The first part of the paper (CP1)

covers a statement of the problem or issue the policy is

trying to address,

as well as the origins and history of the policy.

What do we know about the problem in terms of its prevalence or incidence,

and (if relevant) how does this problem relate to or intersect with other similar areas?

What is the history of the policy:

how did it emerge/develop

how has it changed or evolved over time?

should be a minimum 10 doublespaced

pages using traditional font sizes and margins.

For each paper, please put your name

on a cover page, along with the title of your paper. Please also number your pages. Please prepare each paper in Word and use the following naming convention for each

submitted file: LastName_FirstName_CP#

Annotated Bibliography


The main arguments are that other factors will reduce fatal encounters. It is hard to determine whether or not BWC is the solution to fatal police encounters because of the other factors that cause deadly police encounters. The first factor they feel will reduce fatalities is to build trust within the community. The second factor is people feel like the police should not be handling situations with homeless people and people with mental health issues. They feel like social workers, and mental health workers should address those problems. The article argues about the role of body-worn cameras (BWC) in minimizing the killing of citizens by police. The report covers the importance of BWC in the police force as a part of the technological reforms that aim to improve the sector and make the police more accountable and minimize their engagement in police brutality.

The research studies agencies had BWCs between 2013/14 and 2015/16 and agencies that did not get them up to 2016. The study uses a difference in differences approach. “The study shows Two out of three DID analyses showed statistically significant negative effects of BWCs on citizen fatalities.” (Page 1) The authors came to that answer by going over research in a survey for those years. The surveys asked whether they were likely to get cameras or already have cameras. The study then looked at an equation to estimate the percentage of fatality counts for different years to determine whether or not it will increase or decrease.


This is a useful source. The sources’ strength is the data collected during the surveys that can show whether or not BWC made a difference. The weakness of the source is basing an equation on whether BWC will reduce police fatalities. The research article helped support that BWC has a benefit in police reforms. It works with other reforms in reducing citizen fatalities caused by police since the cameras promote accountability. 


The source is important for my research project, offering support in the argument that body cameras used by police are a technology that reduces police brutality. The article has not changed my perception of the importance of BWCS. I do not think BWC reduces police use of force because people are still dying. Officers are fully aware of the difference between appropriate force and non-appropriate force. I believe some people have the mindset of fear for their lives. Many people that died at the hands of the police were unharmed and did not threaten the officer’s safety. The source is objective.

Retrieved from: Miller, J., & Chillar, V. (2021). Do Police Body-Worn Cameras Reduce Citizen Fatalities? Results of a Country-Wide Natural Experiment. Journal of Quantitative Criminology. https://eds-p-ebscohost-com.umasslowell.idm.oclc.org/ 


The main argument is that BWC invades individual privacy, broadens state control, and unevenly targets minority communities. The article expresses the role of body-worn cameras by the police as the current technological reform having a significant effect in reducing police brutality and reducing discrimination and politics. The BWC is there to make the police conduct their work within the law provisions and prevent them from using force. BWC minimizes the cases where the police discriminate against people based on their race or gender because their work will be evaluated using the camera-recorded information for accountability purposes. The study focuses on the effects that BWC has on black and brown communities. They use research on randomized controlled trials. 


The article is of value to my research, where I learned about the value that the BWC technology brings in transforming the police force for the better. The report has supporting evidence that contributes to already collected literature. The source is objective. The strength is showing research on how BWC reduces citizens’ complaints. The weakness is the BWC not telling whether someone was racially profiled. There is some question the BWC cannot answer simply from the video. 


 Compared to the other sources, the article has highlighted that the cameras minimize the radicalization of power and eradicate inequalities that make the police work according to the law provisions. I can use this source in my research, explaining that there are more than just BWC that will help reduce police fatalities and how officers will also need to implement those things. I can also suggest how to do the research or what topics to research. 

Retrieved from: Henne, K., Shore, K., & Harb, J. (2021). Body-worn cameras, police violence and the politics of evidence: A case of ontological gerrymandering. Critical Social Policy, 026101832110339. https://journals-sagepub-com.umasslowell.idm.oclc.org/doi/pdf/10.1177/02610183211033923 

Summary: The article by Taeho Kim is much comprehensive in discussing the benefits that the BWC brings for the police. There have been controversial complaints about police brutality and have damaged the police legitimacy and reputation. The current intervention towards the sector where the BWC was introduced is of value because it increases the accountability of the police to their actions. The critical reform through BWC is the proper intervention. The study looked at the “causal effects of BWCs on the use of force, enforcement outcomes, and public opinion toward the police in the first nationwide study of over 1,000 local police agencies in the US.” (Page 2) The research supported that the technology reduces police involvement in brutality since the decrease of police homicide involvement was 58%.  


The source is much as significant as others because the evidence is credible in supporting the importance of BWC, which is the main topic in my research. I consider the source beneficial because it will help the other sources prove that BWC reduces police homicides and brutality. The source is objective. The strength of the source is she looks at different reasons why the reduction in force would go down. If there is a policy change or new training, it may help reduce the use of force along with BWC. Those options can also help the use of force go down. So her information would be inaccurate. The weakness in the source is she was unable to test whether BWCs led to reductions in arrests or differences in crime rates. If there is no evidence on those things, the information can be misleading because some officers can deal with twice more people that they have to arrest, leading to the use of force than other officers. So while some cities can show body cams did not change anything, they just may have had to deal with fewer arrests. Another weakness is she bases some of the research on LEMAS surveys of the police chiefs. Some of the police chiefs that are not a fan of body cams may lie and say they are not useful and are a waste of money.


The topic discussed by the article relates to the paper in expressing the role that BWC brings in the police reforms. The article has changed my perception about police reforms and using technology like BWC as the best way to reduce police engaging in brutality. The article showed equations with tables and graphs with high numbers and percentages of BWC, improving the use of force.

Retrieved from: Kim, T., (2019). Facilitating Police Reform: Body Cameras, Use of Force, and LawEnforcement Outcomes. Available at SSRN: http://dx.doi.org/10.2139/ssrn.3474634

Summary: The article by Taeho Kim is much comprehensive in discussing the benefits that the BWC brings for the police. There have been controversial complaints about police brutality and have damaged the police legitimacy and reputation. The current intervention towards the sector where the BWC was introduced is of value because it increases the accountability of the police to their actions. The critical reform through BWC is the proper intervention. The study looked at the “causal effects of BWCs on the use of force, enforcement outcomes, and public opinion toward the police in the first nationwide study of over 1,000 local police agencies in the US.” (Page 2) The research supported that the technology reduces police involvement in brutality since the decrease of police homicide involvement was 58%.  


The source is much as significant as others because the evidence is credible in supporting the importance of BWC, which is the main topic in my research. I consider the source beneficial because it will help the other sources prove that BWC reduces police homicides and brutality. The source is objective. The strength of the source is she looks at different reasons why the reduction in force would go down. If there is a policy change or new training, it may help reduce the use of force along with BWC. Those options can also help the use of force go down. So her information would be inaccurate. The weakness in the source is she was unable to test whether BWCs led to reductions in arrests or differences in crime rates. If there is no evidence on those things, the information can be misleading because some officers can deal with twice more people that they have to arrest, leading to the use of force than other officers. So while some cities can show body cams did not change anything, they just may have had to deal with fewer arrests. Another weakness is she bases some of the research on LEMAS surveys of the police chiefs. Some of the police chiefs that are not a fan of body cams may lie and say they are not useful and are a waste of money.


The topic discussed by the article relates to the paper in expressing the role that BWC brings in the police reforms. The article has changed my perception about police reforms and using technology like BWC as the best way to reduce police engaging in brutality. The article showed equations with tables and graphs with high numbers and percentages of BWC, improving the use of force.

Retrieved from: Kim, T., (2019). Facilitating Police Reform: Body Cameras, Use of Force, and LawEnforcement Outcomes. Available at SSRN: http://dx.doi.org/10.2139/ssrn.3474634