Cohort bias inflates autism trends

Apparent historical increases in autism are exaggerated because older cohorts are undercounted: many were never diagnosed in childhood, and higher mortality among severely affected autistics removes cases before adult surveys. Comparing today’s well‑ascertained children to yesterday’s sparsely diagnosed, partially deceased adults produces a misleading slope. — This cautions policymakers and media against reading long‑run autism graphs as causal evidence and pushes for bias‑aware trend methods before funding or regulatory shifts.