THE EFFECT OF COUNTY-LEVEL PRISON POPULATION GROWTH ON CRIME RATES*

Prior macro-level studies examining the impact of prison population growth on crime rates have produced widely varying results. Studies using national-level time series data find large impacts of prison growth on crime, whereas those using state panel data find more modest ones. Critics of the former studies maintain that the estimates are implausibly large, arguing that the effects are instead due to analysts ’ inability to control for potential confounding factors. Conversely, critics of the lat-ter studies argue that they underestimate the total impacts of imprison-ment by failing to account for potential free-riding effects. This study uses panel data for 58 Florida counties for 1980 to 2000 to reexamine the link between prison population growth and crime. Unlike previous studies, we find no evidence that increases in prison population growth covary with decreases in crime rates. Policy Implications: Our findings suggest that Florida policymakers carefully weigh the costs and benefits of their continued reliance on mass incarceration against the potential costs and benefits of alternatives. If the costs of mass incarceration do not return appreciable benefits, i.e., a reduction in crime, it is time to reconsider our approach to crime and punish-ment. Other research offers evidence of crime prevention programs operating inside the criminal justice system and in communities that hold promise for reducing crime; our findings indicate that policymak-ers carefully consider these options as a way to achieve their goals