Prospective validation before DSM changes

Major psychiatric taxonomy revisions (e.g., DSM criteria changes) should be paired with pre‑implementation, multi‑site prospective validation studies that compare new versus old criteria on the same birth cohorts and clinical populations to quantify reclassification effects on prevalence, service eligibility, and prognosis. Those validation studies and their raw, de‑identified crosswalk data must be published before wide adoption or policy linked to the new criteria. — Requiring prospective field validation would prevent large policy and service shocks driven by definitional drift and make debates about autism prevalence and resources evidence‑based rather than rhetorical.