What is the PSA?

Background: Making Fairer, More Accurate Pretrial Decisions

In the United States, a person's chance of being released or kept in jail before trial is too often determined by their ability to pay money bail, rather than by the threat they pose to public safety or their likelihood of returning to court. Spending just a few days in jail can cost a defendant—who must be presumed innocent before trial—their job, housing, health care services, or custody of their children. Studies show that people who are detained before trial are more likely to plead guilty, be convicted, and reoffend at higher rates.

Moving away from a system based solely on instinct or bail schedules to one in which judges have access to neutral, research-based risk assessments can help to improve judicial decision making, increase public safety, promote the fair treatment of all individuals, and ensure the responsible use of taxpayer funds.

In recognition of these challenges, the Laura and John Arnold Foundation (LJAF) set out to determine whether improvements in the process of pretrial release and detention decisions could offer solutions.

In 2011, LJAF gathered leading criminal justice researchers to design a risk assessment that could be used across jurisdictions, rely solely on administrative data, and be made available to jurisdictions at no cost. The researchers compiled the largest, most diverse set of pretrial records ever assembled—750,000 cases from nearly 300 jurisdictions across the country. The researchers analyzed the data to determine which factors were most predictive of risk of failure to appear and committing a new crime—including a new violent crime—while awaiting trial.

The team worked to eliminate factors that have been shown to introduce race or gender bias into decision making, including factors used by existing assessments, such as housing stability, employment history, and neighborhood. They also eliminated factors that would be difficult or impossible for most jurisdictions to obtain without an interview.

As a result of this analysis, the team arrived at nine factors that were found to be most predictive of failure to appear, new criminal activity, and new violent criminal activity. The nine factors, the weighting of the factors, and the calculations that determine the PSA scores are publicly available.The nine risk factors are:

  • The person's age at the time of arrest
  • Whether the current offense is violent
  • Whether the person had a pending charge at the time of the current offense
  • Whether the person has a prior misdemeanor conviction
  • Whether the person has a prior felony conviction
  • Whether the person has prior convictions for violent crimes
  • Whether the person has failed to appear at a pretrial hearing in the last two years
  • Whether the person failed to appear at a pretrial hearing more than two years ago
  • Whether the person has previously been sentenced to incarceration.

Based on these nine factors, the PSA produces two risk scores: one that predicts a person's risk of failing to return for future court appearances, and the second that predicts their risk of committing a new crime—including a violent crime—if released before trial. The assessment also flags defendants who present an elevated risk of committing a violent crime if released before trial.

The researchers piloted the PSA in 2013 and 2014 throughout the entire state of Kentucky; Mecklenburg County, North Carolina; Santa Cruz County, California; and Gila, Mohave, Pinal, and Yuma Counties in Arizona. Preliminary data from the pilot jurisdictions point to positive change. Jurisdictions reported decreases in jail populations or pretrial detention without increases in crime. Mecklenburg County, for example, experienced a 20 percent decrease in its jail population during the year it implemented the PSA, with no increase in crime rates.

Since its development, researchers have validated the PSA using more than 650,000 cases from diverse jurisdictions in the Northeast, Midwest, West, and two states. In 2018, LJAF issued a Request for Proposals (RFP): To Conduct Research on the Public Safety Assessment, Risk Assessments, and Pretrial Detention. The RFP outlines a robust research agenda that includes the rigorous evaluation of PSA performance, the PSA factors and the manner in which those factors are used to calculate PSA scores, judicial decision making, and system impact, as well as exploratory research projects on new pretrial risk assessment models and the impact of pretrial detention. It is LJAF's hope that this research will give criminal justice professionals a better understanding of the impact of pretrial detention and allow researchers to develop the next generation of risk assessments, ultimately improving upon the PSA itself.

As the public demand for bail reform increases across the United States, judges, lawmakers, prosecutors, public defenders, law enforcement, and advocacy groups are calling for new policies and practices to address the shortcomings of the existing system. LJAF looks forward to working with partners in the pretrial community to make significant and lasting changes that will improve the lives of individuals, families, and communities.