Keith Chen and Jesse Shapiro have published a new paper on prisons that looks quite important, if not exactly earth-shattering. Here's the basic idea: In the federal prison system, before being assigned to a facility, inmates are given a score, reflecting their need for supervision. Prisoners with scores that are above certain cutoff points are put in higher-security prisons, as you'd expect.

So let's say one inmate receives a score of 59, and another receives a score of 60. All told, the second guy really isn't that much more dangerous than the first. But the first guy gets shipped off to a "minimum-security" prison, and the second guy to a "low-security" prison. That's just the way the rules work. Now what Chen and Shapiro found is that the guy who gets bumped up to a higher-security prison is twice as likely to commit a crime in the three years after he's released. The prison conditions themselves are the ostensible cause here.

That doesn't strike me as surprising at all. Someone who enters a higher-security prison is likely going to have more violent peers during his time in jail. He'll probably be exposed to more violence, both from prisoners and guards. He'll probably have more difficulty finding a job after he's released. What else would we expect? A person subjected to higher levels of brutality is more likely to become brutal himself. And indeed, Chen and Shapiro found that being put in a higher-security prison makes you much more likely to commit a violent crime after being released. It swamps any "deterrent" effect that prisons may have on the recidivism rate.

So harsher prison conditions don't actually reduce recidivism, they increase it. Hard time hardens prisoners. And so on. Most people realize this, but it's nice to see it measured. For the record, I'll point out that a large number of people arrested for non-violent drug crimes are sent to higher-security prisons, where, as Chen and Shapiro show, they're more likely to become the sort of people who commit violent crimes. The "War on Drugs" truly is the gift that keeps on giving.

One could also note the perverse fact that the state relies, at least implicitly, on other prisoners to make prison a "punishing" experience. Although no one would ever say so in court, the threat of being raped, for example, is a very real part of being sentenced. This makes the punishment aspect very arbitrary, since the awfulness of your prison sentence is, to some extent, weakly correlated with the badness of your crime, and strongly correlated with totally unrelated things, like whether you have friends on the inside, how tough you look, etc. I don't think we should go back to whipping people who commit crimes, but to some extent it would be a less arbitrary punishment than prison.