children cooked by lead (house paint, dominant for births roughly 1910 to 1955, plus leaded gasoline peaking around 1972) became the adults who acted out decades later, each in the calendar year they reached the age that behavior happens. this is an ecological association across birth cohorts, not a claim about any individual.
childhood lead rose with the US car fleet from about 6 ug/dL in 1930 to a peak near 22 ug/dL at 1972, then fell off a cliff after the 1975 catalytic-converter mandate. the defensible claim is the rise-and-fall pattern as cohorts move through it (the canonical Nevin / Reyes result, with the pre-peak rise now visible too). series that do not fit are kept and sequestered with a stated reason, not deleted. that honesty is part of the argument.
panel 1
one cohort, marched through its life by age
the 1971 to 1976 birth cohort (peak childhood lead). each dot is the calendar year that cohort reached the modal age for that outcome. read left to right: school-leaving and young-offender age around 1990, fraud and financial-failure age in the 2000s, midlife now. green = direction matched the lead hypothesis, amber = it did not (kept, not hidden).
panel 2
cohort overlay explorer
panel 3
correlation: CORE (headline) vs SEQUESTERED (kept, reasoned)
the headline rests on the strong CORE fits, sorted top to bottom by strength: robbery (r=+0.93), fraud-perpetration arrests (+0.92), cigarettes per capita (+0.89), high-school dropout (+0.85), motor-vehicle death rate (+0.82). bar length is the Pearson r between the outcome and the integrated childhood blood lead of the birth cohort that produces it at its modal age.
panel 4
the driver: US childhood blood lead, 1900 to 2023
era-by-era childhood blood-lead reconstruction (Nevin 2007 USA panel, McFarland-Hauer 2022 PNAS birth-cohort shares, Annest 1983 NHANES II 1976-80, Pirkle 1994 NHANES III, Egan 2021, Nriagu 1990 gas-lead tonnage, Mielke paint-era reasoning). pre-1976 absolute level +/- 3 ug/dL, shape (low to 1930, ramp through gas era, peak ~22 ug/dL at 1972, post-phaseout cliff) well constrained. the cohort signal speaks to both the rise and the fall.
defensibility. these are ecological (population) associations between an outcome and the integrated childhood blood lead of the birth cohort that produces it at its modal age. association is not proof. lead is treated as a contributing, necessary-not-sufficient factor, not a sole cause. because childhood lead rose with the gas era then fell off a cliff after 1976, the defensible claim is the post-phaseout decline, not any mid-century rise. sequestered series are retained with a stated mechanism, never deleted. sources: recovered Reuters lead data; EPA EJScreen; CDC NCHS; FBI UCR and BJS; US Courts; Federal Reserve; NHTSA; NCES; Census; NIAAA; Fraser, Murderland (2025); driver Annest 1983 / NHANES / Pirkle 1994 / CDC.
