Lead Water Pipes in 1900 Caused Higher Crime Rates in 1920

Last year I wrote about a paper that looked at the relationship between childhood lead poisoning and violent crime rates in a whole new way. James Feigenbaum and Christopher Muller compared cities from the early 20th century that installed lead water pipes with those that installed iron pipes, and found that cities with lead pipes had higher homicide rates. Today, Josh Marshall alerts me to the fact that Feigenbaum and Muller have now published a final draft of their paper. The basic results are below:...
http://www.motherjones.com/kevin-drum/2016/05/lead-water-pipes-1900-caused-higher-crime-rates-1920