I don't think anyone thinks the deterrent effect of prisons are ineffective. However, the at-risk populations who most often end up in prison are bad at weighin

I don't think anyone thinks the deterrent effect of prisons are ineffective. However, the at-risk populations who most often end up in prison are bad at weighing these deterrents, especially before they go there. Another factor is the quality of deterrence: the point is not to arbitrarily and randomly ruin peoples' lives. You want a high ratio of crime reduction to damage. A good penal system does this and bad penal system works the other way around. A lot of science suggests that the life-ruining factor is a significant counter-effect to the original goal of reducing crime and increasing quality of life in our democracy. That's me being polite. If I was less polite, I would say how much I hate your ignorant, lazy self-righteousness and how this despicable and inhuman attitude is a major factor in how our system destroys people with little to no scientific justification.