At this point, it’s no longer necessary to explain how unprecedented incarceration is in the United States today. The highest incarceration rate in the world (outside of tiny Seychelles); 5% of the world’s population but 25% of its prisoners (Walmsley 2015). 1 Yet there has been some good news recently: after nearly forty years of almost unceasing growth, prison populations in the US dropped for four of the five years between 2010 and 2014. The decline wasn’t great—about 4%, and under 2% if we omit California—but incarceration growth was never going to stop on a dime. Any sort of drop after four decades of unrelenting rise is laudable. 2