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Evaluating the Effects of Police Body-Worn Cameras: A Randomized Controlled Trial

NCJ Number
Date Published
October 2017
32 pages

This paper seeks to fill a gap in the research about the effects of body-worn cameras on police and civilian behaviors.


The authors of this working paper describe their research into the impacts of body-worn cameras (BWCs) on police and civilian behaviors. The authors discuss the study design, measurement strategies, provide graphs and charts, and discuss their research findings. In order to estimate the average effects of BWCs, the authors conducted a randomized controlled trial involving 2,224 Metropolitan Police Department (MPD) officers in Washington, DC. Their pre-analysis plan was publicly registered in advance, and they compared officers randomly assigned to wear BWCs to officers in the control group who did not wear BWCs. The authors measured primary outcomes through documented use of force and civilian complaints, as well as judicial outcomes. The authors conclude that they are unable to detect any statistically significant effects of the BWCs, and they suggest that expectations for the effects of BWCs should be recalibrated and law enforcement agencies that are considering the adoption of BWCs should not expect dramatic reductions in use of force or complaints, or other large-scale shifts in police behavior, solely from the use of cameras.

Date Published: October 1, 2017