Then there are the after-effects, and this is where it gets most complicated. Being in prison you could imagine, could reduce the amount of crime you commit afterwards. Maybe you learn to read, or you’re helped off of your drug problem, or you’re scared straight by the experience. But it’s also easy to imagine that being in prison just makes things worse. That you’re more alienated from society, that you’re closer friends with other criminals, and you learn from their techniques, or you have less ability to get a real job because you’re marked as a felon.
With 698 inmates per 100,000 citizens, the U.S. is the world’s leader in incarcerating people. But what effect does this actually have on crime?
According to David Roodman, Senior Advisor to Open Philanthropy, the marginal effect is zero.
This stunning rebuke to the American criminal justice system comes from the man Holden Karnofsky called “the gold standard for in-depth quantitative research”. His other investigations include the risk of geomagnetic storms, whether deworming improves health and test scores, and the development impacts of microfinance – all of which we also cover in this episode.
In his comprehensive review of the evidence, David says the effects of crime can be split into three categories; before, during, and after.
Does having tougher sentences deter people from committing crime? After reviewing studies on gun laws and ‘three strikes’ in California, David concluded that the effect of deterrence is zero.
Does imprisoning more people reduce crime by incapacitating potential offenders? Here he says yes, noting that crimes like motor vehicle theft have gone up in a way that seems pretty clearly connected with recent Californian criminal justice reforms (though the effect on violent crime is far lower).
Finally, do the after-effects of prison make you more or less likely to commit future crimes?
This one is more complicated.
His literature review suggested that more time in prison made people substantially more likely to commit future crimes when released. But concerned that he was biased towards a comfortable position against incarceration, David did a cost-benefit analysis using both his favoured reading of the evidence and the devil’s advocate view; that there is deterrence and that the after-effects are beneficial.
For the devil’s advocate position David used the highest assessment of the harm caused by crime, which suggests a year of prison prevents about $92,000 in crime. But weighed against a lost year of liberty, valued at $50,000, and the cost of operating prisons, the numbers came out exactly the same.
So even using the least-favourable cost-benefit valuation of the least favourable reading of the evidence — it just breaks even.
The argument for incarceration melts further when you consider the significant crime that occurs within prisons, de-emphasised because of a lack of data and a perceived lack of compassion for inmates.
In today’s episode we discuss how to conduct such impactful research, and how to proceed having reached strong conclusions.
We also cover:
- How do you become a world class researcher? What kinds of character traits are important?
- Are academics aware of following perverse incentives?
- What’s involved in data replication? How often do papers replicate?
- The politics of large orgs vs. small orgs
- How do you decide what questions to research?
- How concerned should a researcher be with their own biases?
- Geomagnetic storms as a potential cause area
- How much does David rely on interviews with experts?
- The effects of deworming on child health and test scores
- Is research getting more reliable? Should we have ‘data vigilantes’?
- What are David’s critiques of effective altruism?
- What are the pros and cons of starting your career in the think tank world? Do people generally have a high impact?
- How do we improve coordination across groups, given our evolutionary history?
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The 80,000 Hours podcast is produced by Keiran Harris.