Megan Stevenson (UVa) begins a recent paper, A Decomposition of Racial Disparities in Pretrial Detention, with the observation that "[U]nderstanding what causes racial disparity in criminal justice is an important step towards learning how to ameliorate it." And to this end, the paper dives deeply into bail data from Philadelphia courts. Specifically, the data set covers all Philadelphia arrests in which charges were filed between September, 2006 and February, 2013, and involves 86,469 white and 172,860 black defendants.
The paper's main--and intriguing--take-away is that "differences in ability/willingness to pay bail are a substantial contributor to the race gap in pretrial detention, particularly at the higher end of the bail distribution." The paper's abstract follows.
"Understanding what causes racial disparity in criminal justice is an important step towards learning how to ameliorate it. Previous research on racial disparities in pretrial detention have focused primarily on evaluating the racial bias of judges, but racial differences in ability-to-pay to monetary bail could also contribute. In this paper I conduct a Oaxaca decomposition of racial disparities in pretrial detention to determine how much is due to black defendants having higher bail and how much is due to black defendants being less likely to post, conditional on the bail amount. Using detailed court records from Philadelphia, I find that differences in the ability to post bail account for 1/3 of the race gap in detention. Differences in posting rates are particularly pronounced at the higher quantiles of the bail distribution: white defendants who must pay a bail deposit of $2500 to secure release are twice as likely to post as black defendants with that same bail. Racial differences in the bail distribution are substantial, but disappear entirely once legally relevant characteristics such as charge, criminal history, age and gender are accounted for. Finally, I discuss how racial differences in bail posting rates complicates tests of racial bias."