Broadest Study Yet Uses Scientific Process to Measure Impact of Police Body-Worn Cameras
Mayor Muriel Bowser releases the findings from a scientifically rigorous evaluation of the Metropolitan Police Department’s (MPD) body-worn camera program. The study, facilitated by The Lab @ DC, a team of applied scientists, used scientific processes to measure the impact of body-worn cameras in the District. Data was collected from June 2015 through March 2017. With more than 2,220 patrol officers and sergeants involved, this is one of the largest and most comprehensive body-worn camera studies currently available.
“Our police department has always valued a strong relationship with the residents and visitors it serves. We invested in one of the most comprehensive deployments of body-worn cameras in the nation to ensure even greater transparency and accountability,” said Mayor Bowser. “As we conclude this comprehensive study, we will recommit ourselves to always evaluating what works—and what does not—to better serve our residents and create a safer, stronger DC.”
From the beginning, the study prioritized scientific rigor and transparency. The Lab @ DC created a detailed pre-analysis plan that described the planned methodology and statistical analyses to be used in the study. This plan was shared publicly, including on the Open Science Framework, before the data were analyzed. The Lab @ DC hosted eleven events between October 2016 and May 2017 to discuss the body-worn camera program and the study. This outreach ensured that neither The Lab @ DC nor MPD could change the analytic approach at any point to support a particular outcome.
MPD staff worked with The Lab @ DC to design and implement a randomized controlled trial—a test design in which individual officers were randomly assigned to either wear a body camera or not. Using administrative data, the primary outcomes of interest measured were documented uses of force and civilian complaints as well as a variety of additional policing activities and judicial outcomes. The recently completed study found no statistically significant average effects on the measured outcomes. However, the study notes that the results do not exclude that the use of body-worn cameras in law enforcement might provide other valuable information.
“Good training and trust is built before a body-worn camera is put into service,” said David Yokum, Director of the Lab @ DC. “Additional research that focuses on how camera footage is used in an evidentiary capacity—such as in court, officer training, and personnel matters—may show that a greater value of this tool exceeds traditional ideas.”
Nearly one year since the deployment of their body-worn cameras, MPD is now able to use their footage for training purposes and is also beginning to see cases in which footage is available matriculate through the judicial system.
“Our comprehensive body-worn camera program is one of the ways we can continue building on the trust we have with the community,” said MPD Chief Peter Newsham. “Not only does it offer greater transparency, it has allowed us to evaluate split-second decisions officers are making to improve our training. The comprehensive study only reassures us that body-worn cameras are an invaluable technology for our department and the community.”