Research on Policing Reform and Accountability

Our Research

Statistical Methods

We work hard to improve measurement and quantitative research on policing, especially on the problem of quantifying racial bias.

Policy Evaluation

We evaluate policy interventions to see how they affect policing outcomes.

Public Opinion & Education

We engage in research on how the mass public perceives policing and crime, as well as in public-facing education.

The Role of Officer Race and Gender in Police-Civilian Interactions in Chicago

Diversification is a widely proposed policing reform, but its impact is difficult to assess. We used records of millions of daily patrol assignments, determined through fixed rules and preassigned rotations that mitigate self-selection, to compare the average behavior of officers of different demographic profiles working in comparable conditions. Relative to white officers, Black and Hispanic officers make far fewer stops and arrests, and they use force less often, especially against Black civilians.

Administrative Records Mask Racially Biased Policing

We show that if police racially discriminate when choosing whom to investigate, analyses using administrative records to estimate racial discrimination in police behavior are statistically biased, and many quantities of interest are unidentified – even among investigated individuals – absent strong and untestable assumptions. Using principal stratification in a causal mediation framework, we derive the exact form of the statistical bias that results from traditional estimation.

Militarization Fails to Enhance Police Safety or Reduce Crime but May Harm Police Reputation

Using a rare geocoded census of SWAT team deployments from Maryland, we show that militarized police units are more often deployed in communities with large shares of African American residents, even after controlling for local crime rates. Using nationwide panel data on local police militarization, we demonstrate that militarized policing fails to enhance officer safety or reduce local crime.