In 1972, there were 174,000 inmates in state prisons around the country. The number today is one 1,400,000. But now, for the first time, the total has dropped, if only slightly. The Pew Center on the States reports that the combined prison population is down by about 5,700 inmates. Though it’s just 0.4% less than it was last year, the decline could have long-term significance. Adam Gelb, Director of the Center’s Public Safety Performance Project, explains what it has to do with the economy and new ideas about public safety.