Public Safety Assessment: Risk factors and formula

Research shows that defendants who pose little threat to public safety but cannot afford to pay money bail often spend unnecessary time in jail awaiting trial, while defendants who pose a threat to public safety are frequently released from pretrial detention.

In partnership with leading criminal justice researchers, the Laura and John Arnold Foundation developed the Public Safety Assessment (PSA) to improve pretrial decision making by providing judges with more information.

Researchers designed the PSA based on the largest, most diverse set of pretrial records ever assembled—750,000 cases from nearly 300 jurisdictions. Based on a comprehensive analysis of the data, researchers identified the nine factors that best predict pretrial risk of failure to appear (FTA), new criminal activity (NCA), and new violent criminal activity (NVCA). The nine factors relate to a person’s age, current charge, and criminal history. The PSA does not rely on factors such as race, ethnicity, or geography.

Since its development, researchers have validated the PSA using more than 650,000 cases from across the country, and further independent research is ongoing. Early research indicates that the PSA is proving to be a reliable and accurate predictor of pretrial outcomes.

Risk Factors

The table below outlines the nine factors used by the PSA and illustrates which factors are used to predict each of the pretrial outcomes—Failure to Appear (FTA), New Criminal Activity (NCA), and New Violent Criminal Activity (NVCA).

Risk FactorPretrial Outcome
1. Age at current arrest
2. Current violent offense
2A. Current violent offense and 20 yrs. old or younger
3. Pending charge at the time of the offense
4. Prior misdemeanor conviction
5. Prior felony conviction
5A. Prior conviction (misdemeanor or felony)
6. Prior violent conviction
7. Prior failure to appear in the past two years
8. Prior failure to appear older than two years
9. Prior sentence to incarceration

Factor Weighting

Each of the risk factors is weighted and assigned different points, according to the strength of the relationship between the factor and the specific pretrial outcome. The total points assigned to FTA and NCA are converted to two separate scales that range from 1 to 6, with higher scores indicating a greater level of risk. The total points assigned to NVCA is converted to a yes-no “violence flag.”

The tables below illustrate how points are assigned to the risk factors for each pretrial outcome and how the total points are converted to the scaled FTA and NCA scores, as well as the NVCA flag.

Judicial Discretion

The PSA results give judges additional information to help guide their pretrial decisions. The PSA does not replace judicial discretion. The PSA scores and flag are intended to augment the experience and wisdom that a judge brings to the critical decisions of detaining or releasing a defendant pretrial.

PSA Implementation

LJAF makes the PSA available at no cost to jurisdictions. A series of instructional guides and supporting resources are available to criminal justice professionals as they take steps to successfully incorporate the PSA into their pretrial systems. The materials are designed to help a jurisdiction’s project champion, project leader, and implementation team implement the PSA in a manner that maximizes the PSA’s ability to provide judges with relevant and reliable information.