The Effect of Incarceration on Re-Offending: Evidence from a Natural Experiment in Pennsylvania

This paper uses a sample of U.S. offenders from Pennsylvania to estimate the effect of incarceration on post-release criminality. To do so, we capitalize on a feature of the criminal justice system in Pennsylvania—the county-level randomization of cases to judges. We begin by identifying five counties in which there is substantial variation across judges in the uses of incarceration, but no evidence indicating that the randomization process had failed. After demonstrating covariate balance that is consistent with randomization, we estimate a series of confidence intervals for the effect of incarceration on one year, two year, five year, and ten year rearrest rates. On the whole, there is little evidence in our data that incarceration impacts rearrest. 1 This work was generously supported by National Science Foundation Grants SES-102459 and SES-0647576. We are also grateful to Mark Bergstrom for coordinating the data collection with the PSC, PA DOC, and the PA State Police 2 Authors listed alphabetically