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Measuring the Direct and Spillover Effects of Body-Worn Cameras on the Civility of Police–Citizen Encounters and Police Work Activities

NCJ Number
Journal of Quantitative Criminology Volume: 36 Dated: December 2020 Pages: 851-876
Date Published
October 2019
26 pages

This paper reports on a research study that uses a simultaneous quasi-experimental design to test for direct and spillover effects of body-worn cameras on the civility of police-citizen encounters as well as policework activities; it lays out the study’s methodology, outcomes, and conclusions.


Existing research on the effects of body-worn cameras (BWCs) have found largely consistent results regarding direct significant reductions in citizen complaints and often also report reductions in use of force reports. However, few studies have examined possible spillover effects on untreated officers. This study explicitly tests for direct and spillover effects of BWCs on the civility of police-citizen encounters and police work activities. This study assesses the direct effects of BWCs on citizen complaints, police use of force, and police proactivity and discretion during a 1-year randomized controlled trial in the Boston Police Department. Through a simultaneous quasi-experimental design, this study also investigates whether BWC deployment results in spillover effects onto control officers in treated districts as compared to comparison officers in untreated districts. Findings indicate that the use of BWCs reduces citizen complaints and police use of force but has no appreciable impact on officer activity or discretion. Furthermore, results indicate significant spillover reductions in citizen complaints for control officers in treated districts. The results of this study suggest that a limited BWC adoption may generate spillover deterrent impacts as officers and citizens perceive an increased threat that inappropriate and illegal behaviors will be captured on video even when BWCs are not actually present during an encounter. Partial BWC implementation seems like a cost-effective alternative to full implementation. However, police executives and policy makers need to think carefully about possible negative externalities generated by uneven BWC coverage. (Published Abstract Provided)

Date Published: October 1, 2019