If police departments better reflected the racial makeup of the communities they served, would incidents of police violence drop? That rationale seemed intuitive, and Ferguson, Mo., offered fertile ground for testing the theory. In 2015, two in three residents in the city of 21,000 were black, but only three officers in the 53-member force were. This disparity appeared as a tangible underlying factor that may have contributed to Brown’s death. Black people are involved in and are victims of police-involved killings at greater proportions than any other racial group, but research findings on the role of race in police violence have been inconclusive and sometimes contradictory, NPR reports.
A study to be published in the Public Administration Review will complicate that body of research even more. “What we find is evidence that [having] more black police officers probably doesn’t offer a direct solution to this problem,” says Sean Nicholson-Crotty, a political scientist at Indiana University. The researchers concluded that as the ratio of black officers in police departments rose — up to a certain threshold — so did the number of fatal encounters between officers and black residents. When black officers reach 25 percent of the police force, the rate of fatal police-involved incidents levels off. The study also found that once a police department became about 40 percent black, the trendline flipped — the more black officers a department has after that point, the less likely the incidence of fatal encounters with black people. The study suggests that what departments really need isn’t just to simply add more black officers, but to reach a critical mass of black officers. In fact, so many black officers that they would be overrepresented relative to the local black population. Only 15 of the 100 largest cities have 40 percent black officers.