Do Judges Vary in Their Treatment of Race?

TLDR

Minorities may face systematic racial differences in legal outcomes, but unobservable case characteristics make it hard to assess treatment differences. The study estimates judge‑to‑judge variation in minority sentencing by exploiting random case assignment to control for unobservable case characteristics. They measure between‑judge differences in the racial gap in incarceration rates and sentence lengths, using a Monte Carlo simulation to construct a counterfactual where race has no effect. The analysis reveals significant judge‑to‑judge variation in incarceration rates for African American versus white defendants, but no such variation in sentence lengths.

Abstract

Are minorities treated differently by the legal system? Systematic racial differences in case characteristics, many unobservable, make this a difficult question to answer directly. In this paper, we estimate whether judges differ from each other in how they sentence minorities, avoiding potential bias from unobservable case characteristics by exploiting the random assignment of cases to judges. We measure the between-judge variation in the difference in incarceration rates and sentence lengths between African American and white defendants. We perform a Monte Carlo simulation in order to explicitly construct the appropriate counterfactual, in which race does not influence judicial sentencing. In our data set, which includes felony cases from Cook County, Illinois, we find statistically significant between-judge variation in incarceration rates, although not in sentence lengths.