The Impact of Long Sentences on Public Safety: A Complex Relationship
The Role of Certainty
A foundational principle in criminology and modern criminal justice policy is that the certainty of receiving a punishment is a more powerful crime deterrent than the severity of that punishment or sanction. Certainty of apprehension, however, is difficult to measure for individuals not already engaged in the criminal justice system. Therefore, the studies reviewed below attempt to estimate a deterrent effect for justice-involved individuals. One quasi-experimental evaluation focused on more than 1,000 people enrolled in a behavior-modification program targeting individuals on probation with substance use disorders. Results indicated that the threat of swift, consistent, and shorter periods of imprisonment fostered greater compliance with the conditions of probation. Program participants had fewer probation revocations (9% compared to 31% of probationers in the comparison group of people not enrolled in the behavior-modification program) and spent fewer days in prison (112 days, on average, compared to 303 days for the comparison group).
Other, more recent studies using DNA registries show that individuals are less likely to reoffend when they know their genetic data is already stored, reaffirming the importance of certainty of apprehension for the specific deterrent effect. Unfortunately, the DNA-related findings may not be readily applicable to individuals engaging in crimes that typically result in long sentences, as more than half (52%) of serious violent crime goes unreported to law enforcement agencies.
