Body-worn cameras (BWCs) are one of the most rapidly spreading technologies in policing today. As of 2016, the U.S. Bureau of Justice Statistics estimated that 60 percent of local police departments and 49 percent of sheriffs’ offices in the United States were using BWCs for all of their officers.¹ The U.S. federal government has facilitated this trend by providing tens of millions of dollars for BWC acquisition and training since 2015. The adoption of BWCs in the United States has been propelled by a crisis of legitimacy in policing, caused largely by controversial police shootings and the perception of aggressive crime control techniques, particularly in minority communities. Advocates of BWCs believe that the use of these cameras can reduce unjustified use of force by police, promote accountability for police misconduct, discourage unfounded or frivolous complaints against police, and improve community-police interactions more generally. However, some have also worried that BWCs might encourage de-policing, encroach on individuals’ privacy, discourage crime reporting and cooperation from community members, or have other unintended effects. There are also questions about the best uses and policies for implementing BWCs. Nonetheless, widespread adoption has moved forward in the absence of much evidence to guide police on these issues.

Researchers have developed a substantial body of research on BWCs in just the last few years. In the most comprehensive review to date on BWCs, the authors and their colleagues Megan Stoltz and Amber Scherer, reviewed 70 studies that have examined more than 110 outcomes associated with this technology.² These studies have been conducted in a variety of settings including small and large agencies in the United States and other countries.

In general, research findings indicate that officers seem supportive of BWCs, particularly as they gain more experience with them. Increasingly, officers value BWCs as a tool for their protection (against false or exaggerated accusations of wrongdoing), for evidence collection of criminal wrongdoing, and to increase the accuracy of their reporting. It may be fair to say, however, that BWCs have not produced dramatic changes in police behavior, for better or worse. Although early findings indicated BWCs reduce the use of force by officers, more recent findings have been mixed, perhaps as a result of variations in agency policies regarding how the devices should be used (for example, whether or not they should be activated at all times). A more encouraging finding is that BWCs seem to reduce complaints against officers. The question remains, however, whether and to what degree these changes reflect community members’ reporting behaviors (they might be less inclined to file minor or unfounded complaints) or improvements in officers’ behavior or their interactions with community members. Indeed, it is not clear from available evidence that BWCs improve community members’ satisfaction with police encounters, as might be expected if BWCs were having substantial effects on police behavior. In sum, BWCs may curb some of the worst police behaviors but have little impact otherwise.

Similarly, fears of “de-policing” (sometimes referred to as the “Ferguson Effect”) from the use of BWCs have not been realized. Arrests seem as likely to increase as to decrease with the use of BWCs, perhaps suggesting that adoption of the cameras leads to more formal and legalistic responses to citizens but only in some contexts. Otherwise, BWCs do not seem to have discouraged most proactive field contacts or officer-initiated activities. But police proactivity is complex; community members might want some types of police proactivity to decline (for example, indiscriminate stop-question-and-frisks or misdemeanor arrests for recreational drug use), but they might want other types of proactivity to increase (e.g., problem-solving, community engagement, targeted enforcement in high-crime places). From an evidence-based perspective, the hope is that BWCs do not cause police to stop carrying out positive, proactive activities that can prevent and reduce crime and that do not generate negative reactions from community members.

For their part, community members are also generally supportive of police using BWCs, although this support comes with important caveats. For example, support for BWCs can also be contingent on a community member’s age, race, and experience with the police (i.e., younger and non-white individuals may see fewer benefits of BWCs). Additionally community satisfaction with the police seems to be determined by the way officers treat and interact with people, not necessarily whether an officer is wearing a camera. (In fact, studies suggest that people cannot consistently remember if officers were wearing BWCs.) Studies also indicate varying results of the impact of BWCs on the behavior of community members. While more studies have found no significant differences between officers with and without BWCs in terms of assaults upon them or reports of resisting arrest, a few studies have showed assaults against officers increased for officers wearing BWCs. As noted, BWCs may discourage people from filing complaints against police, but this may not necessarily translate into more positive views of police. BWCs also might exacerbate an already challenged relationship between the community and the police, especially if community members expect the cameras to be used to increase police accountability and transparency, but officers primarily use them to increase the accountability of community members. Indeed, studies have found that BWC footage is most often used to prosecute individuals for crimes they commit and can be useful in increasing the probability of pleas, convictions, and criminal charging.

Overall, then, perhaps anticipated effects from BWCs have been overestimated. If true, this should not be surprising, given the mixed, modest, and sometimes unintended effects that technologies have more generally in policing. However, several caveats are in order. Although the number of BWC studies is large overall, the number of evaluations for any particular outcome is still often small, and findings are thus subject to change. As the evidence base grows, the field should also gain a better sense of contextual factors (e.g., agency policies, uses of BWCs, and community contexts) that might be associated with desired and undesired outcomes.

Finally, the research evidence is still lacking on many important questions about BWCs. For example, one question that has yet to be studied is whether BWCs can reduce criminal justice disparities, in particular, those disparities resulting from implicit or explicit biases. It also unknown whether BWCs affect the legality of police actions (for example, adherence to Fourth Amendment standards); whether BWCs affect community members’ willingness to report crime and cooperate in police investigations; or whether there are differential impacts of BWCs on different groups of people or officers. Perhaps most importantly, the effects of BWCs on police organizations are still unknown. If BWCs are to produce substantial changes in police behavior and performance, these changes are most likely to come through their effects on processes and systems in police organizations, particularly those pertaining to training, deployment, supervision, and accountability. Determining how BWCs affect the processes and outcomes of internal police investigations is particularly central to assessing whether BWCs achieve the purpose that was arguably the main driver of their adoption (i.e., improving transparency and accountability in the investigation of serious police misconduct, particularly surrounding the use of deadly force). These changes will come slowly, if at all, and will require long-term attention from the field. Nevertheless, they may be the most consequential for community-police relations and police legitimacy in the long run.

In the meantime, agencies will almost certainly continue to adopt BWCs. Given the ubiquity of personal video and audio recording devices, more and more police agencies are likely to conclude that they need to have their own recording of events for community-police encounters with negative outcomes. A growing expectation among the public that the use of BWCs is a marker of a responsive, transparent, and legitimate police organization is also likely. This will put considerable technical and financial strains on police (and prosecutors) that will also need further attention in cost efficiency analyses. Nevertheless, the behavioral changes in the field may be modest and mixed, at least in the short run.🛡

Notes:

¹ Shelley S. Hyland, Body-Worn Cameras in Law Enforcement Agencies, 2016 (Washington, DC: U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, 2018).

² Cynthia Lum, Megan Stoltz, Christopher S. Koper, and J. Amber Scherer, “The Research on Body-Worn Cameras: What We Know, What We Need to Know,” Criminology and Public Policy (forthcoming, February 2019).

Please cite as

Cynthia Lum and Christopher S. Koper, “The Evidence Base for Body-Worn Cameras: What Law Enforcement Leaders Still Need to Know,” Research in Brief, Police Chief Online, December 28, 2018.