Guidelines for how judges set bail vary across the country, but generally use a combination of a bail schedule, which prices out fees for specific offenses, and their own assessment of whether the defendant will appear at their hearing or commit a crime before their trial. If you can’t pay up, you stay in jail until your trial date, sometimes for up to a month.
On January 1, New Jersey replaced its bail system with an algorithm designed to mathematically assess the risk of defendants fleeing or committing a crime—particularly a violent one—before their trial date. The algorithm, called the Public Safety Assessment, was designed by the Texas-based Laura and John Arnold Foundation, a nonprofit that tries to fund innovative solutions to criminal justice reform.
New Jersey isn’t the first state to use algorithms to help judges suss out high-risk defendants. Counties across the country have tried using computer-based techniques to flag those who should continue to be detained until trial, and those who are flight risks.