MARY LOUISE KELLY, HOST: How long must someone who's committed a crime spend in prison? What's a reasonable sentence to hand down? What's fair? Those are calls that judges across the country make each and every day, and they do so without the benefit of what would seem to be a basic, obvious tool. In many states, courts lack a comprehensive database on criminal sentences, meaning that judges are often left to their own devices to figure it out. Ohio Court of Appeals Judge Pierre Bergeron and Ohio Supreme Court Justice Michael Donnelly argue in The Atlantic magazine that better sentencing data could make meaningful reform to the criminal justice system. They join me now. Welcome to ALL THINGS CONSIDERED.