In the United States, the steep increase in incarceration rates has accompanied a steep drop in crime. In a 2017 review essay, “The Impacts of Incarceration on Crime,” its author, David Roodman, notes that the “59% per capita rise in incarceration between 1990 and 2010 accompanied a 42% drop in FBI-tracked ‘index crimes.’ ”4 And yet, as Roodman accurately notes, “researchers agree that putting more people behind bars added modestly, at most, to the fall in crime.”
