Responding to our request for more evidence related to the lead/crime connection, a reader points to economist Rick Nevin, one of the leading researchers investigating that connection. Nevin wrote as recently as last month about how different cohorts were affected by lead:
The crime decline in recent years has been slower than the earlier decline in blood lead because steep arrest rate declines for youths have been partially offset by rising arrest rates for older adults. … This shift in arrest rates shows ongoing massive declines for youths born across decades of declining lead exposure, smaller arrest rate declines for adults born in the early years of the lead exposure decline, and increasing arrest rates for older adults born when lead exposure was increasing.
The shift in arrest rates has caused a corresponding shift in prison incarceration. From 2001 to 2013, incarceration rates fell by 59% for males ages 18-19 and 30% for males in their 20s, but increased 33% for men ages 40-44 and surged 86% for men ages 45-54. Proponents of “tough-on-crime” sentencing credit prison incapacitation for much of the USA crime decline – “when a criminal is locked up, he’s not ransacking your house” – but the largest arrest rate declines have occurred among younger age groups with large contemporaneous incarceration rate declines. ... Mendel reports that lead exposure can explain juvenile justice trends that cannot be explained by reform efforts or other crime theories.
Mark Kleiman, on the other hand, voiced skepticism on the lead/crime connection in response to Kevin Drum’s widely lauded 2013 essay, invoking the work of economist Philip J. Cook and criminologist John Laub. Another skeptic at the time was Ronald Bailey: