A new study by the Brennan Center for Justice has concluded that almost 40% of U.S. prison inmates don't need to be behind bars. The study, started in 2012, looked at offender data for around 1.5 million inmates, and found that for 25% of these inmates, an alternative sentence such as probation, fines, community service, or drug treatment would have been more affective than prison. A further 14% of these prisoners had already served enough time, and could be released “with little risk to public safety,” the study concluded. 

“Very long lengths of stay in many many cases do not make people safer,” said Lauren-Brooke Eisen, lead author of the study. “Incarceration is not the right place for so many lower-level offenders in our criminal justice system.” Researchers have found that people jailed for lesser, nonviolent crimes are actually more likely to commit crimes after being released from jail, after associating with more dangerous criminals in prison. Alternative sentencing strategies like community service and drug treatment have been shown to reverse this effect.

“There are so many groups trying to work to end mass incarceration but without a blueprint for exactly how you would do that, it’s really hard to make changes,” Eisen said. “We wanted this report to jump-start a conversation.” The authors of the study recommend that lawmakers eliminate prison as a punishment for low-level crimes, and that current sentence lengths for major crimes should be reduced by up to 25%. This decrease in prison population could save the country $20 billion annually, allowing the nation's incarceration budgets to be directed elsewhere.