IN AMERICA, computers have been used to assist bail and sentencing decisions for years. Their proponents argue that the rigorous logic of an algorithm, trained with a vast amount of data, can make judgments about whether a convict will reoffend that are unclouded by human bias. Two researchers have now put one such program to the test. According to their study, published in Science Advances, COMPAS did neither better nor worse than people with no special expertise.
Julia Dressel and Hany Farid of Dartmouth College in New Hampshire selected 1,000 defendants at random from a database of 7,214 people arrested in Broward County, Florida between 2013 and 2014, who had been subject to COMPAS analysis. They split their sample into 20 groups of 50. For each defendant they created a short description that included sex, age and prior convictions, as well as the criminal charge faced.