Getting the lead out = getting the crime out?

The National Bureau of Economic Research, a dependable source of reading on topics you hadn't thought of, summarizes recent work by Amherst economist Jessica Wolpaugh Reyes on the relationship between reduced lead in the environment and reduced crime a generation later:

In her state-by-state analysis, Reyes controls for other possible determinants of crime rates, including the unemployment rate and per capita income, the number of prisoners and police, gun laws, beer consumption, welfare generosity, the teen pregnancy rate, the population age distribution, and the effective abortion rate. The results suggest that a 10 percent increase in the grams of lead per gallon of gasoline leads to a 7.9 percent increase in violent crime. These results are subjected to a number of sensitivity tests, with particular attention paid to the importance of certain states, the possibility of a non-linear relationship, and the role of alternate lead measures....