Many jurisdictions across the United States are rethinking the “front end” of the criminal justice system — the pretrial period between an arrest and the disposition of a criminal case. Often these reforms focus on the initial decisions that judges and other court stakeholders make about whether to detain individuals in jail while they are awaiting trial, and on the use of money bail as a tool for ensuring that people will show up to court hearings. In most jurisdictions, the majority of people in jail at any point in time are awaiting trial, and many are there because they cannot afford to post bail. Jurisdictions are looking for fairer, more cost-effective approaches to the pretrial phase of the system.

To assist jurisdictions in making better initial decisions, the Laura and John Arnold Foundation (now Arnold Ventures) developed the Public Safety Assessment (PSA), a tool that uses data on an individual’s history with the justice system and the current offense to predict the likelihood that the person will show up to hearings or be arrested for a new crime if released. The PSA aims to help judges make more informed, less subjective decisions about pretrial detention. It is currently used in nearly 40 jurisdictions across the nation.

MDRC evaluated pretrial reforms that included the PSA in several jurisdictions. The evaluation used quantitative and qualitative methods to understand the use of the tool and its impacts on the system in each location. More detailed information about the statistical methods used in this evaluation is available in a technical working paper.