Lead Poisoning caused the 70’s Crime Wave

Philip Cohen points out single mothers could not have caused the cause the 1970s-1990s crime wave with a very simple chart.

“Looking at it from the perspective of 1990, it was easy to assume a strong causal relationship between the rise in single motherhood and the murder epidemic. By my reading of the research, it is true that children of single mothers are more likely to commit crimes. But other factors are more important. That must be the case, or we wouldn’t see the overall trends in the United States split this dramatically starting in the 1990s:”

Fortunately, we know the “other factor” is lead poisoning, at least as answers to these questions:

  • Crime
  • Mental Retardation
  • SAT Scores

I also suspect Tyler Cowen’s Great Stagnation in innovation was caused by lead poisoning. We just were not smart enough to think of useful new technology.

(Via Kevin Drum)


  1. Indeed, this is what I’ve read about for years and seems thus far to be the most convincing explanation. Plus I do think there’s a social epidemic factor that went on primarily in the 80s – as young Americans saw their friends engaging in questionable behavior, they often joined in and thought it was okay to do so. Similarly, when a white man shoots (& kills one) 4 black teenagers attempting to mug him on the subway, he receives an outburst of support by NYC’s denizens tired of crime. Plus the entire story of the crack-cocaine epidemic. These are things you don’t see today.

    I also love the knock on Tyler Cowen.. He seems to be a very superficial thinker in the same vein as the John Cochranes of the world.

  2. The trouble with quantifying crime reports is steroids– no wait, that’s baseball– is that its easier for cops to mark up or down the spreadsheet Ben Bernanke-style than to actually stop crime in the real world.