The study, which was led by Barak Ariel of Cambridge University, integrated the findings of 10 experiments in which police in different cities were randomly assigned to use a body camera during different shifts. Remarkably, the study captured the behavior of over 2,000 police officers and more than two million hours of law enforcement activity. The dismal result: Body cameras had no overall effect on how often police used force and was correlated with a statistically significant increase in assaults on police officers. Although violence between suspects and police went down in a few of the 10 study sites, these benefits were more than cancelled out by other sites where cameras made no difference or made violence more common.
Criminologist David Kennedy said he was disappointed by the study’s findings but not entirely surprised by them. The roots of today's mistrust of police have a long history in many communities, he points out. “Cameras look forward, but trust can't be established without being honest about what’s happened between police and the community in the past, which is a hard thing for folks with power and privilege to acknowledge," he said. "Cameras do not deal with issues of accountability, and angry communities don’t have much faith that information from cameras will be acted upon.”
Does this mean that body cameras are worthless? Ariel and his colleagues cautioned against this conclusion, noting that the variability in their data across the 10 sites shows that “body worn videos worked in some places, some of the time.” Presuming this limited claim is correct, it would still imply that equipping police with cameras is not the panacea it is sometimes portrayed.
The idea that technology can eliminate complex human problems can be quite seductive, as the widespread enthusiasm for body cameras indicates. But without the demanding work required to transform how police departments and minority communities view each other and relate to each other, cameras may serve only to document how bad things are rather than make them any better.
Keith Humphreys is a professor of psychiatry at Stanford University.