Criminal Justice Reform

New York City Release Assessment

The Brooklyn Bridge

The Crime Lab partnered with New York City leaders to update its pretrial release assessment to be more accurate and equitable with the aim of helping judges reduce pretrial incarceration by identifying the vast majority of low-risk defendants who can be released without bail or other pretrial conditions.


Pretrial release decisions are enormously consequential decisions that require judges to balance the costs of detaining a defendant who is presumed innocent against the risks associated with releasing a defendant who may be a harm to others or a flight risk. However, according to behavioral science research, these kinds of probabilistic questions are some of the most difficult for people to accurately assess.


In partnership with the New York City Mayor’s Office of Criminal Justice, the Criminal Justice Agency (CJA), Luminosity, and others, the Crime Lab leveraged the latest insights from data science to build the CJA Release Assessment. This tool helps judges better identify the vast majority of low-risk defendants who can be released without bail or other pretrial conditions. The research team uses data from prior NYC cases – of which there are millions – to construct a decision aid that helps to reduce pretrial incarceration.

Project overview

At the start of every criminal case in New York City, a judge must make a critical decision: whether a defendant should be released before their trial, have bail set, or be detained. Historically, the judge decided based on a personal prediction of the defendant’s risk for not showing up for court. Yet despite this decision’s enormous impact, a large body of behavioral science research tells us that all people, including judges, have incredible difficulty accurately assessing probabilities of future events. In the courtroom, this thinking trap results in many people who were at low-risk for missing court ending up detained, while many high-risk defendants are released. Improving the accuracy of this crucial risk prediction could prevent thousands of jail admissions each year without threatening New York City’s reputation as the safest big city in the country. 

Years Active

2017 – present

Project Leads

Jens Ludwig

Jens Ludwig

Pritzker Director

Greg Stoddard

Greg Stoddard

Senior Research Director

Related Resources
Updating the New York City Criminal Justice Agency Release Assessment

Updating the New York City Criminal Justice Agency Release Assessment

Jun 2020
New York City Criminal Justice Agency Release Assessment

New York City Criminal Justice Agency Release Assessment

Jan 2020

The Crime Lab worked with the Mayor’s Office of Criminal Justice in New York City, the Criminal Justice Agency, as well as other city, state, and nonprofit partners to build, test, and implement a risk assessment instrument called the Release Assessment, which replaced NYC’s prior risk assessment that had been last updated in 2003. The Release Assessment is a data-driven decision aid that helps judges better identify how likely a given person is to return for all required court dates.

Before implementing the updated tool in courtrooms citywide, we tested the tool by seeing how it would have assessed past cases. We leveraged the latest data science to analyze information about more than 1.8 million cases in New York City between 2009 and 2015. By looking at patterns in past cases (which defendants successfully returned to court and what characteristics those defendants tended to have), the research revealed eight easily interpretable factors which, in combination, are most predictive of future court appearance. These eight factors (which do not include race, age, or gender) represent the algorithm that underpins the CJA Release Assessment.  The Release Assessment went live in late 2019 and is currently being used to support judges in deciding on the conditions of a defendant’s pretrial release. 

The Release Assessment increased both the accuracy and equity over the prior pretrial tool NYC was using. Under that prior tool, only 35% of defendants were recommended for release without conditions. The updated CJA Release Assessment recommends 89% of defendants for release. Moreover, whereas the prior tool had a substantial difference in the rate at which White and Black defendants were recommended for release without conditions, the new Release Assessment effectively reduced that gap to zero.

And because of the increased accuracy of this data-driven tool, the CJA Release Assessment can recommend far more defendants for release without any projected increase in missed court appearances. In sum, the CJA Release Assessment has the potential to help thousands of New Yorkers – in particular, people of color – avoid unnecessary pretrial incarceration at Rikers Island.