Study Finds Increased Incarceration Has Marginal-to-Zero Impact on Crime


More incarceration will not make us safer, a new report by the Vera Institute of Justice concludes, because increased incarceration rates have no demonstrated effect on violent crime and in some instances may increase crime.

The Prison Paradox summarizes research about the relationship between incarceration rates and crime rates, finding that since 2000, the increased use of jails and prisons accounted for nearly zero percent of the overall reduction in crime.

Instead, between 75 and 100 percent of the drop in crime rates since the 1990s is explained by other factors, including the aging population, increased wages, increased employment, increased graduation rates, increased consumer confidence, increased law enforcement personnel, and changes in policing strategies.

Research shows that any crime reduction benefits from increased incarceration apply only to property crimes. Higher incarceration rates are not associated with lower violent crime rates, because expanding incarceration primarily means that more people convicted of nonviolent, “marginal” offenses (like drug offenses and low-level property offenses) and “infrequent” offenses are imprisoned.

Vera found that the United States spent roughly $33 billion on incarceration in 2000 for roughly the same level of public safety it achieved in 1975 for $7.4 billion. Mass incarceration also imposes significant social, cultural, and political costs, reducing employment opportunities, reducing earnings, limiting economic mobility, and increasing the chances that children of incarcerated parents will live in poverty and engage in delinquent behavior.

Incarceration is not only “an expensive way to achieve less public safety,” but it may actually increase crime by breaking down the social and family bonds that guide individuals away from crime, removing adults who would otherwise nurture children, depriving communities of income, reducing future income potential, and engendering a deep resentment toward the legal system.

Over the past two decades, 19 states have successfully decreased both imprisonment and crime rates, using crime prevention, alternative-to-incarceration, and community corrections approaches. Vera reports that the state with the largest drop in incarceration rates (New Jersey, with a 37 percent decrease between 2000 and 2015) also saw a 30 percent decrease in crime rates during this period. West Virginia, with the largest increase in incarceration rates (83 percent), experienced a 4 percent increase in crime rates. Indeed, only four states in this period experienced increases in crime rates, and all four also saw increased incarceration rates.

Vera points out a number of approaches that have proven to be less expensive and more effective in improving public safety than incarceration. For example, place-based problem-oriented policing approaches that involve carefully analyzing crime and disorder in a small area and devising tailor-made solutions, from repairing fences and improving lighting to removing graffiti and nuisance abatement, have been shown to significantly reduce crime rates.

Law enforcement-led diversion programs that divert individuals at the point of arrest and prosecution-led diversion programs that divert individuals either pre-charge or defer prosecution post-charge have been shown to reduce future criminal activity of program participants.

And several community corrections approaches, which provide supervision and services to individuals in the community post-conviction, can reduce criminal activity among participants without the use of incarceration.

The report concludes that “policymakers can reduce crime without continuing to increase the social, cultural, and political costs of mass incarceration by investing in more effective and efficient crime reduction strategies that seek to engage the community, provide needed services to those who are criminally involved, and begin to address the underlying causes of crime.”