A research collection

The Leaded Generation

America had a 1990s violent-crime drop nobody can fully explain. Fraud arrests peaked thirty years later. Personal bankruptcy peaked forty years later. Every cohort that walked through its twenties between 1990 and 2016 broke something the previous cohort did not. The thing they all share: they were born when childhood lead exposure was at its highest in US history.

Childhood lead exposure rose with the US car fleet. About 6 ug/dL in 1930. About 10 ug/dL in 1950. About 22 ug/dL at the 1972 peak, the highest a generation of children has ever been measured at. Then the catalytic-converter mandate forced gasoline lead out and the curve fell off a cliff. American children born roughly 1955 to 1980 grew up at or near that peak. They became the adults who acted out, decades later, each in the year they reached the age the behavior happens. This collection lays the argument out honestly, shows the evidence three different ways, and lets you see where your own cohort sits.

Ecological association, not individual causation. Lead is treated as a contributing, necessary-not-sufficient factor. Series that do not fit the pattern are kept with a stated reason, never deleted. Each tool below names its Source.