Kentucky lawmakers thought requiring that judges consult an algorithm when deciding whether to hold a defendant in jail before trial would make the state’s justice system cheaper and fairer by setting more people free. That’s not how it turned out.

Before the 2011 law took effect, there was little difference between the proportion of black and white defendants granted release to await trial at home without cash bail. After being mandated to consider a score predicting the risk a person would reoffend or skip court, the state’s judges began offering no-bail release to white defendants much more often than to blacks. The proportion of black defendants granted release without bail increased only slightly, to a little over 25 percent. The rate for whites jumped to more than 35 percent. Kentucky has changed its algorithm twice since 2011, but available data shows the gap remained roughly constant through early 2016.