What Happens to Imprisonment Rates When a Progressive Prosecutor Is Elected?: Quasi-Experimental Evidence from Cook County

Background and Purpose: There has been a clear recognition in recent years that the United States’ extremely high rates of imprisonment, coupled with significant racial disparities, are problematic. The progressive prosecutor movement has developed in response to these issues and has gained increasing attention over the past decade. Despite the growing importance of the progressive prosecutor movement in criminal legal reform efforts, we know little about the extent to which electing a progressive chief prosecutor actually leads to reductions in overall imprisonment rates and racial disparities in imprisonment, with no studies to our knowledge using data that captures pre-election differences in imprisonment trends across jurisdictions. In this study, we begin to fill this gap by examining the implications of the 2016 election of Kim Foxx (one of the most prominent progressive prosecutors in the country) in Cook County, Illinois for overall, Black, White, and Latinx imprisonment rates.

Methods: To assess the impact of Kim Foxx’s election on imprisonment, we created a panel dataset that captures imprisonment rates overall, Black imprisonment rates, White imprisonment rates, and Latinx imprisonment rates from 2006 to 2019 in all Illinois counties. To create this data set, we drew upon county level end-of-year imprisonment data from the Illinois Department of Corrections and county level population data from the CDC Wonder Database. Then, we employed a quasi-experimental synthetic control approach for each of the four outcomes described above, where we matched the treated county (Cook County) to the weighted combination of counties that most closely matched Cook County’s pre-treatment trends in the outcome of interest. Placebo-in-space estimates were used to determine the statistical significance of the synthetic control estimates.

Results: We find evidence that the election of Kim Foxx was associated with statistically significant reductions in the overall imprisonment rate (roughly an 11% reduction by 2019), the White imprisonment rate (nearly a 1/3^rd reduction by 2019), and the Black imprisonment rate (a reduction of approximately 20% by 2019). We do not find evidence that Kim Foxx’s election was associated with changes in the Latinx imprisonment rate. Since the White imprisonment rate declined proportionally more than the Black and Latinx imprisonment rates, our results do not suggest that Kim Foxx’s election ameliorated racial disparities in imprisonment. In fact, Black and Latinx individuals were still more than 15 and 3 times more likely, respectively, to be imprisoned than White people in Cook County as of 2019.

Conclusions and Implications: Electing a progressive prosecutor has the potential to lead to significant reductions in imprisonment. However, at least in Cook County, doing so did not result in substantial reductions in racial disparities in imprisonment. Progressive prosecutor decarceration efforts that aim to reduce racial disparities likely need to move beyond efforts to reform punishment around non-violent offenses. Specifically, reforms will also likely need to change how we punish violent and repeat offenses.