There’s a saying that there’s nothing like going to prison to turn you into a criminal. But now, a new study offers evidence that this homily is statistically sound. Every year a person is kept in prison increases their odds of committing another crime when they are released.


Over at Quartz, Allison Schrager explains the study, which only deals with the United States:

A new paper from University of Michigan economics professor Michael Mueller-Smith measures how much incapacitation reduced crime. He looked at court records from Harris County, Texas from 1980 to 2009. Mueller-Smith observed that in Harris County people charged with similar crimes received totally different sentences depending on the judge to whom they were randomly assigned. Mueller-Smith then tracked what happened to these prisoners. He estimated that each year in prison increases the odds that a prisoner would reoffend by 5.6% a quarter. Even people who went to prison for lesser crimes wound up committing more serious offenses subsequently, the more time they spent in prison. His conclusion: Any benefit from taking criminals out of the general population is more than off-set by the increase in crime from turning small offenders into career criminals. High recidivism rates are not unique to Texas: Within 5 years of release more than 75% of prisoners are arrested again.


In other words, the prison system does not deter crime. It encourages it. Especially for people who serve more than a year.

But why would that be? Schrager talks about a number of popular theories, the most salient of which is that it’s incredibly hard for ex-cons to get jobs. Employers don’t want a former prisoner working for them, and when money gets tight, it’s easier to turn to crime than it is to become homeless or go hungry. Plus, the threat of prison doesn’t scare criminals enough to prevent them from committing crimes. The fact is that people need money in their pockets more than they fear getting caught for breaking the law.

The question is, how can we prevent crime while also eliminating the long prison sentences that lead to higher rates of recidivism? One possibility might be to put more police officers on the street. Apparently, there is a lot of evidence that increasing police presence actually does deter crime in a way that fear of prison doesn’t. The goal shouldn’t be more arrests, though. It should be stopping crime before it happens.

[via Quartz]

Contact the author at annalee@gizmodo.com .

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