By Charles E. Loeffler and Daniel S. Nagin

The US prison population stands at 1.43 million persons, with an additional 740,000 persons in local jails.Nearly all will eventually return to society. This review examines the available evidence on how the experience of incarceration is likely to impact the probability that formerly incarcerated individuals will reoffend. Our focus is on two types of studies, those based on the random assignments of cases to judges, called judge instrumental-variable studies, and those based on discontinuities in sentence severity in sentencing grids, called regression discontinuity studies. Both types of studies are designed to account for selection bias in nonexperimental estimates of the impact of incarceration on reoffending. Most such studies find that the experience of postconviction imprisonment has little impact on the probability of recidivism. A smaller number of studies do, however, find significant effects, both positive and negative. The negative, recidivism-reducing effects are mostly in settings in which rehabilitative programming is emphasized and the positive, criminogenic effects are found in settings in which such programming is not emphasized. The findings of studies of pretrial incarceration are more consistent—most find a deleterious effect on postrelease reoffending. We also conclude that additional work is needed to better understand the heterogeneous effects of incarceration as well as the mechanisms through which incarceration effects, when observed, are 6 generated. For policy, our conclusion of the generally deleterious effect of pretrial detention adds to a larger body of evidence pointing to the social value of limiting its use.

Annu. Rev. Criminol. 2022. 5:133–52