Are Machines Biased or Are We Biased Against Machines?

Earlier this week, ProPublica published a damning article on the use of algorithms in the criminal justice system. In the article, titled "Machine Bias", they studied how a widely used algorithm differs in how accurately it predicts the recidivism of different races. And their findings are troubling: the algorithm systematically under-predicts the recidivism of white criminals and over-predicts the recidivism of black criminals. This has important consequences, since recidivism -- a criminal's propensity to commit a future crime -- is a large factor in determining sentencing and rehabilitation requirements. As with all things statistical, it is important to get the nuances correct.