What the researchers found was striking. The kids who ended up incarcerated were 13 percentage points less likely to graduate high school and 22 percentage points more likely to end up back in prison as adults than the kids who went to court but were placed under, say, home monitoring instead. (This was after controlling for family background and so forth.) Juvenile detention appeared to be creating criminals, not stopping them.
The authors lay out a couple of reasons why this would be. Going to prison can obviously disrupt school and make it harder to get a job later on. But also, as other researchershave found, many people who end up behind bars end up making friends with other offenders and building “criminal capital.” Prison turns out to be excellent training for a life of crime.