Sentence Length and Recidivism: A Review of the Research

In response to prison overcrowding concerns in recent years, many U.S. officials have undertaken efforts to reduce sentence lengths for certain crimes. However, it is unclear how these changes affect recidivism rates. Among the research on incarceration and recidivism, the majority of studies compare custodial with noncustodial sentences, while fewer examine the impact of varying incarceration lengths. This article reviews the research on the latter. Overall, the effect of incarceration length on recidivism appears too heterogeneous to draw universal conclusions, and findings are inconsistent across studies due to methodological limitations. For example, many study samples are skewed toward people with shorter sentences while others include confounds that render results invalid. Of the studies reviewed, some suggested that longer sentences provide additional deterrent benefits in the aggregate, though some studies also had null effects. None suggested a strong aggregate-level criminogenic effect. We argue that a conclusion that longer sentences have a substantial criminogenic effect, large enough to offset incapacitative effects, cannot be justified by the existing literature.