Share this comment
I grew more doubtful as i researched it, but the thing that really clinched it for me was the 5th graph in section 3.
The increase in crime in the 60s was a period effect, not a cohort effect. Every age group became more violent at the same time, they weren't lead poisoned one after another.
Analyzing by cohory also…
https://medium.com/@tgof137/debunking-the-lead-crime-hypothesis-949e6fc2b0dc
I grew more doubtful as i researched it, but the thing that really clinched it for me was the 5th graph in section 3.
The increase in crime in the 60s was a period effect, not a cohort effect. Every age group became more violent at the same time, they weren't lead poisoned one after another.
Analyzing by cohory also helps to understand the peak of crime in the late 80s/early 90s. You can rule out the abortion/crime hypothesis the same way.
I should say it's hard to call either theory completely debunked -- lead or abortion could both have some subtle (10%?) effect on crime and it would be hard to prove or disprove that. But neither one is the kind of unifying theory of crime rates that it promises to be.