Pretrial risk assessment tools (RATs) are decision-making algorithms that use information about a person accused of a crime to try to predict the likelihood of certain outcomes if they are released from jail before their trial.

RATs usually input data about a person’s demographic information, such as age or employment status, as well as criminal legal history, such as prior arrests or convictions. These inputs are weighed to create a final score that is meant to represent the statistical chance of this person safely returning to court for their court dates or being arrested again.

These “risk” scores then guide judges and magistrates’ decisions about pretrial supervision conditions or whether or not they are released.

Whether or not someone is released before their trial can have a huge impact on the outcome of their case.1Juleyka Lantigua-Williams: Why poor, low-level offenders often plead to worse crimes, The Atlantic That’s why it is so important to understand how these tools work, and recognize the bias that is built into algorithms like RATs.

This section explores the basics of pretrial RATs: what they are, how they work, the most common tools, and why we should care about them in pretrial justice systems.

Read an overview of what risk assessment tools and algorithms are in the Risk Assessment Tools section. Examine how all kinds of algorithms, including pretrial risk assessments, can embed bias and may not be as objective as they appear in the Bias in Algorithms section.

Learn about the specifics of how pretrial RATs gather information and produce scores in the Pretrial Risk Assessment Tools section, with a focus on the specific Inputs, Outputs, and Validation statistics in these subsections.

Explore both sides of the debate surrounding RATs: Why Jurisdictions Choose RATs, a section detailing arguments that proponents of these tools may make, and RATs Don’t Solve Pretrial Injustice, a section that outlines our key concerns with these tools.

Discover the factors and brief histories of the most widespread tools we found in our research in the Common Pretrial Risk Assessments section. Run through one common tool as it is implemented in New Jersey in the Public Safety Assessment Simulator.