Judging disparities: Recidivism risk, image motives and in-group bias on Wisconsin criminal courts

This paper studies racial in-group disparities in Wisconsin, which has one of the highest Black-to-White incarceration rate ratios among all U.S. states. The analysis is motivated by a model in which a judge may want to incarcerate more due to three factors: (1) when the defendant has higher recidivism risk and is more likely to commit future crimes; (2) when the defendant is from a different group (anti-out-group preferences); and (3) when the defendant is of the same group but that group is responsible for a majority of crimes (image motives). Further, a judge may have better information on recidivism risk due to two factors: (4) becoming more experienced, and (5) sharing the same group as the defendant. We take these ideas to new data on 1 million cases from Wisconsin criminal courts, 2005-2017. Using a recidivism risk score that we construct using machine learning tools to predict reoffense, we find evidence that judges do tend to incarcerate defendants with a higher recidivism risk (1). Consistent with judge experience leading to better information on defendant recidivism risk (4), we find that more experienced judges are more responsive in jailing defendants with a high recidivism risk score. Looking at racial disparities between majority (White) and minority (Black) judges and defendants, we find no evidence for anti-out-group bias (2). Consistent with image motives (3), we find that when the minority group is responsible for most crimes, minority-group judges are harsher on their in-group. Finally, consistent with judges having better information on recidivism risk for same-group defendants (5), we find that judges are more responsive to the recidivism risk score for defendants from the same group.