January 17, 2015


The Effect of Police Body Cameras (Alex Tabarrok, January 13, 2015, Marginal Revolution)

The first randomized controlled trial of police body cameras shows that cameras sharply reduce the use of force by police and the number of citizen complaints.

We conducted a randomized controlled trial, where nearly 1,000 officer shifts were randomized over a 12-month period to treatment and control conditions. During ''treatment shifts'' officers were required to wear and use body-worn-cameras when interacting with members of the public, while during ''control shifts'' officers were instructed not to carry or use the devices in any way. We observed the number of complaints, incidents of use-of-force, and the number of contacts between police officers and the public, in the years and months preceding the trial (in order to establish a baseline) and during the 12 months of the experiment.

The results were that police use of force reports halved on shifts when police wore cameras. In addition, the use of force during the entire treatment period (on shifts both using and not using cameras) was about half the rate as during pre-treatment periods. In other words, the camera wearing shifts appear to have caused police to change their behavior on all shifts in a way that reduced the use of force.

Posted by at January 17, 2015 7:25 AM

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