Crime rates in the United States have declined to historical lows since the early 1990s. Prison and jail incarceration rates as well as community correctional populations have increased greatly since the mid-1970s. Both of these developments have disproportionately impacted poor and minority...

We evaluate the effect of perhaps the largest exogenous decline in a state's incarceration rate in U.S. history on local crime rates. We assess the effects of a recent reform in California that caused a sharp and permanent reduction in the state's incarceration rate. We exploit the large...