Police lethal violence against Black people may affect clearance of crimes involving Black victims

Police use of violence, especially against Black people, may threaten police agencies' effectiveness by reinforcing residents' legal cynicism and leading to disengagement from police. For example, after the killing by police of George Floyd, a Milwaukee police official said local residents cooperated less with police than they did before the killing.

A new study examined police lethal violence against Black people and its relationship with crime clearance by arrest—a measure of the solvability of a crime when an offender is arrested or processed for further prosecution—involving Black victims. The study found some support for the idea that police lethal force against Black people is negatively associated with crime clearance of incidents involving Black victims, but the authors say their findings are not definitive.

The study, by researchers at the University of Wisconsin (UW)-Milwaukee, appears in Criminology & Public Policy, a publication of the American Society of Criminology.

"Citizen cooperation is vital to police investigations that lead to arrests," explains Aki Roberts, associate professor of sociology at UW-Milwaukee, who led the study. "To the extent that police violence against Black people hinders citizen engagement with police and threatens Black residents' cooperation with crime investigations, it could reduce clearance of crimes involving Black people. Our study is the first to examine the relationship between police use of lethal force and crime clearance."

In the United States, crime clearance rates are quite low, with Black homicide victims' cases less likely to be cleared than those of their White counterparts. In this study, researchers examined a sample of crimes involving Black victims in more than 350 jurisdictions in 2015. They used lethal violence data from the Mapping Police Violence (a Black Lives Matter-affiliated tally of people killed by police since 2013) and crime incident and clearance data from the National Incident-Based Reporting System (NIBRS) produced by the Federal Bureau of Investigation.

The impact of police lethal violence does not last forever; instead, negative feelings toward police after such violence tend to diminish over time, though they can reappear after a new event. The researchers constructed a time-varying measure of each crime's exposure to police lethal violence in its local jurisdiction. They also assessed the impact of nationally prominent events of police lethal force against Black people on residents' responses to local police violence.

Jurisdictions with higher typical exposure to police killings of Black victims exhibited lower levels of crime clearance of Black victims' crimes, with this relationship more apparent for non-lethal violent offenses than for homicides. But the authors suggest that this finding should be interpreted with caution because it may be driven by a correlation between an agency's average exposure to police killings and some agency or jurisdiction characteristics that were not included in the model. For example, in jurisdictions with more police violence, there may already be a generally distrustful relationship between police and the Black community.

Given these inconclusive findings, the authors suggest addressing the question of why there might or might not be a relationship between police killings and crime clearance. Among their explanations: Even people who distrust the broader institution of policing may still view the police as providers of necessary assistance in certain circumstances and hold a variety of complicated motivations that could still encourage them to cooperate with specific crime investigations. Conversely, citizens in some jurisdictions may be so cynical about police that an additional killing by police would not change their attitudes. Another possibility is that the effect of police violence on residents is so transitory that it does not influence residents' willingness to cooperate for more than a short period of time.

The study suggests that in addition to reducing instances of police lethal violence through better training and vetting of officers and improvement of non-lethal means of subduing suspects, local police agencies should accelerate their adoption of policing practices and organizational characteristics that could enhance police legitimacy and citizen cooperation in the Black community, especially in jurisdictions with high exposure to police violence. Other steps to take include requiring police to wear body-worn cameras, increasing minority representation and leadership in police agencies, and promoting perceptions of procedural justice in Black communities.

Among the study's limitations, the authors note that the NIBRS includes data on only a portion of the many incidents that may be relevant to crime clearance, underrepresents larger cities, and does not provide detailed geographical information for crimes. "Our main analysis using the specific timing of agencies' police lethal violence events did not find significantly reduced clearance in those agencies following these events. However, additional exploratory analyses suggested that there could be such an impact, but for a shorter time than we had initially hypothesized," notes John M. Roberts Jr., professor of sociology at UW-Milwaukee, who coauthored the study. "This possibility should be investigated in further research."