Do the Effects of Police Body-Worn Cameras on Use of Force and Complaints Change Over Time? Results From a Panel Analysis in the Milwaukee Police Department

• Published date: 01 June 2021
• DOI: 10.1177/0093854820970583
• Author: Bryce E. Peterson,Daniel S. Lawrence
• Date: 01 June 2021
• Subject Matter: Articles

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

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

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© 2020 International Association for Correctional and Forensic Psychology

734

DO THE EFFECTS OF POLICE BODY-WORN

CAMERAS ON USE OF FORCE AND

COMPLAINTS CHANGE OVER TIME?

Results From a Panel Analysis in the Milwaukee

Police Department

BRYCE E. PETERSON

DANIEL S. LAWRENCE

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

INTRODUCTION

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: bpeterson@urban.org.

970583CJBXXX10.1177/0093854820970583Criminal Justice and BehaviorPeterson, Lawrence / Short Title

research-article2020

Peterson, Lawrence / EFFECTS OF POLICE BODY-WORN CAMERAS OVER TIME 735

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