Meh, probably not:
http://stevenpinker.com/files/pinker/files/pinker_comments_on_lead_removal_and_declining_crime.pdf
There are reasons to be skeptical of any claim based on correlations between such widely separated variables as lead exposure (the cause) and crime (the effect). Consuming lead does not instantly turn someone into a criminal in the way that consuming vitamin C cures scurvy. It affects the child’s developing brain, which makes the child duller and more impulsive, which, in some children, and under the right circumstances, leads them to grow up to make short-sighted and risky choices, which, in some children and under the right circumstances, leads them to commit crimes, which, if enough young people act in the same way and at the same time, affects the crime rate. The lead hypothesis correlates the first and last link in this chain, but it would be more convincing if there were evidence about the intervening links. Such correlations should be far stronger than the one they report: presumably most kids with lead are more impulsive, whereas only a minority of impulsive young adults commit crimes. If they are right we should see very strong changes in IQ, school achievement, impulsiveness, childhood aggressiveness, lack of conscientiousness (one of the “Big Five” personality traits) that mirror the trends in lead exposure, with a suitable time delay. Those trends should be much stronger than the time-lagged correlation of lead with crime itself, which is only indirectly related to impulsiveness, an effect that is necessarily diluted by other causes such as policing and incarceration. I am skeptical that such trends exist, though I may not be aware of such studies.
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Also, the parallelism in curves for lead and time-shifted crime seem too good to be true, since the lead hypothesis assumes that the effects of lead exposure are greatest in childhood. But 23 years after the first lower-lead cohort, only a small fraction of the crime-prone cohort should be lead-free; there are still all those lead-laden young adults who have many years of crime ahead of them. Only gradually should the crime-prone demographic sector be increasingly populated by lead-free kids. The time-shifted curve for crime should be an attenuated, smeared version of the curve for lead, not a perfect copy of it. Also, the effects of age on crime are not sharply peaked, with a spike around the 23rd birthday, and a sharp falloff—it’s a very gentle bulge spread out over the 15-30 age range. So you would not expect such a perfect time-shifted overlap as you might, for example, for first-grade reading performance, where the measurement is so restricted in time.
Finally, the most general reason for skepticism about a causal hypothesis based on epidemiological correlations between a widely separated cause and effect is that across times and places, many things tend to go together. Neighborhoods next to smoggy freeways also tend to be poorer, more poorly policed, more poorly schooled, less stable, more dependent on contraband economies, and so on. It’s all too easy to find spurious correlations in this tangle – which is why so many epidemiological studies of the cause and prevention of disease (this gives you cancer; that prevents it) fail to replicate.
It sounds like Pinker is unfamiliar with most of the research on the topic. He refers to this graph, but not any of the research on the various other predictions that you could derive from the hypothesis that lead caused much of the hump in crime over the past 60 years.
The things that he says about priors, and about the sorts of research that he'd like to see, sound plausible, but I wouldn't put much stock in what he says about the state of the research.
Summary
I'd like to increasing the well-being of those in the justice system while simultaneously reducing crime. I'm missing something here but I'm not sure what. I'm thinking this may be a worse idea than I originally thought based on comment feedback, though I'm still not 100% sure why this is the case.
Current State
While the prison system may not constitute an existential threat, At this moment more than 2,266,000 adults are incarcerated in the US alone, and I expect that being in prison greatly decreases QALYs for those incarcerated, that further QALYs are lost to victims of crime, family members of the incarcerated, and through the continuing effects of institutionalization and PTSD from sentences served in the current system, not to mention the brainpower and man-hours lost to any productive use.
If you haven't read these Meditations on Moloch, I highly recommend it. It’s long though, so the executive summary is: Moloch is the personification of the forces of competition which perverse incentives, a "race to the bottom" type situation where all human values are discarded in an effort to survive. That this can be solved with better coordination, but it is very hard to coordinate when perverse incentives also penalize the coordinators and reward dissenters. The prison industrial complex is an example of these perverse incentives. No one thinks that the current system is ideal but incentives prevent positive change and increase absolute unhappiness.
The incentives have come far out of line with human values. What can be done to bring incentives back in alignment with the common good?
My Proposal
Using a model that predicts recidivism at sixty days, one year, three years, and five years, predict the expected recidivism rate for all inmates at all individual prison given average recidivism. Sixty days after release, if recidivism is below the predicted rate, the prison gets a small sum of money equaling 25% of the predicted cost to the state of dealing with the predicted recidivism (including lawyer fees, court fees, and jailing costs). This is repeated at one year, three years, and five years.
The statistical models would be readjusted with current data every years, so if this model causes recidivism to drop across the board, jails would be competing against ever higher standard, competing to create the most innovative and groundbreaking counseling and job skills and restorative methods so that they don’t lose their edge against other prisons competing for the same money. As it becomes harder and harder to edge out the competition’s advanced methods, and as the prison population is reduced, additional incentives could come by ending state contracts with the bottom 10% of prisons, or with any prisons who have recidivism rates larger than expected for multiple years in a row.
Note that this proposal makes no policy recommendations or value judgement besides changing the incentive structure. I have opinions on the sanity of certain laws and policies and the private prison system itself, but this specific proposal does not. Ideally, this will reduce some amount of partisan bickering.
Using this added success incentive, here are the modified motivations of each of the major actors.
Roadmap
If it could be shown that a model for predicting recidivism is highly predictive, we will need to create another model to predict how much the government could save if switching to a bonus system, and what reduction of crime could be expected.
Halfway houses in Pennsylvania are already receiving non-recidivism bonuses. Is a pilot project using this pricing structure feasible?