Association for Public Policy Analysis & Management

Police officer body-worn cameras (BWCs) have been promoted as a technological mechanism that will improve policing and the perceived legitimacy of the police and legal institutions. While there is a national movement to deploy BWCs widely, BWCs are financially costly and involve new administrative complexities, including officer training and the storage and dissemination of video footage. In addition, difficult questions related to privacy remain unresolved. A nationwide survey found that 95% of police departments across the country either have already or intend to implement a BWC program [1]. However, there is little evidence to date on whether BWCs actually have the anticipated impacts. Though several evaluations have been completed and others are in progress, most appear to be small- to medium-sized (n < 500), and few evaluations have employed a randomized controlled trial (RCT), in which officers are randomly assigned to wear a BWC or not [2]. The lack of random assignment makes causal inference difficult for these studies; their small size makes power considerations paramount, as many of the outcomes presumed to be affected by BWCs are relatively rare, such as citizen complaints of police behavior.

Our study of the District of Columbia’s Metropolitan Police Department (MPD) body-worn camera program tackles both of these issues: we use an RCT design to evaluate the effects of BWCs citywide. The department is currently in the process of deploying 2,800 BWCs to its police force, offering a unique opportunity to run an RCT, in which 50% of all full duty patrol and station officers will be randomly assigned to wear BWCs. The larger sample size of the MPD study—to our knowledge one of the largest randomized controlled trials of a BWC program in the country—enables us to detect more precisely the effects of BWCs on police and citizen behavior as well as their evidentiary value in both internal affairs investigations and criminal justice proceedings.

While the RCT is scheduled to continue until December 2016, preliminary results from the first phase of the study (conducted in two of the seven police districts) offer early insights on the effects of BWCs. In addition,  by disseminating lessons learned from the design and implementation of our BWC program and study—including the process for collaborating with academic researchers to rigorously evaluate the effects of BWCs—we hope to make a valuable contribution to our understanding of how this new technology affects law enforcement and criminal justice outcomes.

[1] Mike Maciag, “Survey: Almost All Police Departments Plan to Use Body Cameras,” Governing.com, January 26, 2016.

[2] See Michael D. White, Police Officer Body-Worn Cameras: Assessing the Evidence (U.S. Department of Justice: Office of Justice Programs, 2014). and Cynthia Lum, Christopher Koper, Linda Merola, Amber Scherer, & Amanda Reioux, Existing and Ongoing Body Worn Camera Research: Knowledge Gaps and Opportunities: A Research Agenda for the Laura and John Arnold Foundation (Phase 1 Report), Fairfax, VA (2015): Center for Evidence-Based Crime Policy, George Mason University.