https://www.bu.edu/av/core/journal/xxiii/Neminski.pdf
Frankly most of the studies are about what to do about the recidivism issue as opposed to asking whether or there is one.
The incarceration rate has skyrocketed since Nixon and overall crime rates have remained steady. Violent crimes spiked over Nixon and Reagan's administrations attributed to the drug war.
I'm getting pretty sick of my tax dollars going toward people that don't need punishment, but help, mental illness and addiction are not crimes, if you smoke some dope and stay home, ok. If you smoke some dope and go commit a real crime, rot in jail. Stop building more prisons for non violent drug offenders. Joe apparently made some dumb mistakes, which speak more about his character than a stupid drug. I drink, but I don't break the law, if this was the 20,s I'd be locked up, and I don't even want to bring up the war on drugs, I'll say it's unwinnable, that's it.