Study: No association between diversification of US police departments and clearance rates of crimes against minorities

Along with high rates of crime relative to other developed nations, the United States’ crime clearance rates—the rates at which crimes are solved—are alarmingly low. One way to raise crime clearance rates is to diversify police departments. A new study examined the effect of diversification of police departments on clearance of aggravated assaults in U.S. police agencies. None of the measures of representation studied were significantly associated with clearance of victims’ assaults.

The study, by researchers at the University of Wisconsin Milwaukee (UWM), appears in Criminology & Public Policy.

“Less than half of crimes in the United States are cleared,” explains Aki Roberts, associate professor of sociology at UWM, who led the study. “Citizen cooperation in crime investigations can help lead to arrests, which raises the rates of crime clearance. But citizen engagement with police in minority communities tends to be low.”

To address these issues, efforts have been made to diversify police agencies racially and ethnically. Greater minority representation is expected to improve police treatment of minority residents and foster a more positive relationship between police and the community. But these efforts also carry the risk that they will be viewed as a naïve panacea that fails to address deep-rooted and longstanding tensions.

In this study, researchers examined more than 350 U.S. police agencies’ levels of racial/ethnic diversity and the arrest clearance of aggravated assaults within their jurisdictions. They used 2016 Law Enforcement Management and Administrative Statistics from the U.S. Department of Justice, as well as data from the U.S. Census Bureau’s American Community Survey to measure three aspects of police diversity in each agency: the percentage of Black officers, the ratio of Black officers to the city’s population, and the presence or absence of Black police leadership.

The study also used data from the FBI’s National Incident-Based Reporting System (NIBRS) to examine nearly 44,000 aggravated assaults of Black victims across 205 police agencies. It also explored equivalent Hispanic police diversity measures, examining nearly 8,400 aggravated assaults with Hispanic victims across 158 agencies.

The study found that none of the diversity measures examined vis a vis Black officers were significantly associated with the clearance of aggravated assaults of Black victims. The study found similar results for the diversity measures vis a vis Hispanic officers and Hispanic victims. The results, which echo those of prior studies, may reflect the idea that diversification does little to change police agency culture and resulting policing style, especially at the relatively low levels of minority representation in most agencies, the authors suggest.

“Although our findings do not point to a benefit of diversity for clearance involving minority victims, it is encouraging that the results do not suggest that increasing minority police representation harms clearance rates,” notes Hannah Smith, a Ph.D. student in sociology at UWM, who co-authored the study.

“Therefore, it appears that police agencies can continue to increase their racial and ethnic diversity without sacrificing clearance rates, a main indicator of police performance. However, we need more research on policing outcomes and diversity, including studies that examine this relationship using data over time.”