Who Watches the Watchmen: Evidence of the Effect of Body-Worn Cameras on New York City Policing

We present a multi-year study of the rollout of Body-Worn Cameras (BWCs) to the New York City Police Department (NYPD). Our study adds to the prior body of work by clarifying some of the discord within it, particularly with respect to large urban police departments. We estimate the effect of BWC deployment on precinct volumes of citizen stops, arrests, complaints against officers, and use-of-force incidents. Results indicate that BWCs drive significant increases in stops and decreases in arrests and citizen complaints. We observe no effect on use of force. We also document heterogeneity in affected stops and complaints. Our findings speak to three potential benefits of BWCs in urban law enforcement: an increase in legitimate stops made by police; a decrease in complaints alleging officers’ abuse of authority; and a reduction in arrests (which appears beneficial, regardless of whether this results from improved behavior among police or citizens).