New Zealand Study Provides More Support for Lead-Crime Hypothesis
I&#x27;ll echo bckygldstn&#x27;s criticisms[1] and add a few of my own.<p>The &quot;lead-crime hypothesis&quot; is a very obvious example of correlation not implying causation.<p>For example, rock music causes crime. Rock music grew in popularity in the late 50&#x27;s and early 60&#x27;s, peaked between the late 60&#x27;s and early 90&#x27;s, and declined thereafter. Just like crime! In fact, the harder they rocked the worse the crime rate got. I guess Tipper Gore was right all along. Rock music causes crime.<p>Margarine causes crime. Johnny Carson causes crime. The Boston Celtics cause crime. The Japanese economy, big hair, VHF television, polyester, yearly Oldsmobile sales: all cause crime.<p>During the period leaded gasoline was sold, Canada allowed 0.77 grams of lead per liter of gasoline, nearly three times the US limit of 0.29 g&#x2F;l.[2] Yet the crime rate in Canada was (and continues to be) far lower than in the US.[3]<p>In Mexico, leaded gas remained commonplace much later than it did in the US, and yet crime fell dramatically during the period leaded gas was sold, and <i>increased</i> dramatically after it stopped being sold.[4]<p>One thing we could look at is people who had the highest lead exposure. Lead miners, paint factory workers, house painters, fuel refinery workers, gas station attendants, auto mechanics, etc. I would confidently bet the farm that, adjusting for sex and income, there was no statistically-significant correlation between these professions and crime.<p>Aviation gasoline, as used in small propeller planes, still contains lead. We could also look at present-day flight instructors, airplane mechanics and people who live near general aviation airports. I would likewise expect there to be no relationship.<p>Here&#x27;s something that&#x27;s known to cause crime: young men. The Baby Boomers were the largest generation ever, which means between the late 60&#x27;s (oldest Boomers entering their late teens) and early 90&#x27;s (youngest Boomers entering their 30&#x27;s), there was a particularly large population of young men. This doesn&#x27;t explain the entire rise and decline in crime (the Boomers weren&#x27;t <i>that</i> much larger than other generations), but it&#x27;s a better starting place than lead paint.<p>[1] <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=16025762" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=16025762</a><p>[2] <a href="http:&#x2F;&#x2F;www.columbia.edu&#x2F;itc&#x2F;sipa&#x2F;envp&#x2F;louchouarn&#x2F;courses&#x2F;env-chem&#x2F;Pb-Rise&amp;Fall(Nriagu1990).pdf" rel="nofollow">http:&#x2F;&#x2F;www.columbia.edu&#x2F;itc&#x2F;sipa&#x2F;envp&#x2F;louchouarn&#x2F;courses&#x2F;env...</a><p>[3] <a href="https:&#x2F;&#x2F;ourworldindata.org&#x2F;wp-content&#x2F;uploads&#x2F;2013&#x2F;03&#x2F;homicide-rates-in-the-united-states-1950-2010-and-canada-1961-2009-pinker-2011-jpg.jpg" rel="nofollow">https:&#x2F;&#x2F;ourworldindata.org&#x2F;wp-content&#x2F;uploads&#x2F;2013&#x2F;03&#x2F;homici...</a><p>[4] <a href="http:&#x2F;&#x2F;www.slate.com&#x2F;content&#x2F;dam&#x2F;slate&#x2F;articles&#x2F;news_and_politics&#x2F;foreigners&#x2F;2014&#x2F;12&#x2F;141209_Charts-Homicide-Rates-Mex.jpg.CROP.promovar-mediumlarge.jpg" rel="nofollow">http:&#x2F;&#x2F;www.slate.com&#x2F;content&#x2F;dam&#x2F;slate&#x2F;articles&#x2F;news_and_pol...</a>