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The Effect of Police Body-Worn Cameras on Use of Force and Citizens' Complaints Against the Police: A Randomized Controlled Trial

NCJ Number
Journal of Quantitative Criminology Volume: 31 Dated: 2015 Pages: 509-35
Barak Ariel; William A. Farrar; Alex Sutherland
Date Published
27 pages

This paper describes the authors’ efforts to determine the effects of body-worn-cameras on the prevalence of use-of-force or citizens’ complaints against the police.


The authors of this study describe their efforts to answer the question of whether or not body-worn-cameras reduce the prevalence of use-of-force and/or citizens’ complaints against the police. The authors describe their methodology, which involved empirically testing the use of body-worn-cameras by measuring the effect of videotaping police–public encounters on incidents of police use-of-force and complaints, in randomized-controlled settings. Over 12 months, the authors randomly-assigned officers to “experimental-shifts” during which they were equipped with body-worn HD cameras that recorded all contacts with the public and to “control-shifts” without the cameras (n = 988). They nominally defined use-of-force, both unnecessary/excessive and reasonable, as a non-desirable response in police–public encounters. The authors estimate the causal effect of the use of body-worn-videos on the two outcome variables using both between-group differences using a Poisson regression model as well as before-after estimates using interrupted time-series analyses. The authors found that the likelihood of force being used in control conditions were roughly twice those in experimental conditions. Similarly, a pre/post analysis of use-of-force and complaints data also supported this result: the number of complaints filed against officers dropped from 0.7 complaints per 1,000 contacts to 0.07 per 1,000 contacts. The authors discuss the findings in terms of theory, research methods, policy and future avenues of research on body-worn-videos. Publisher Abstract Provided