How common is autism, and how early is it being identified? This is the primary-source answer: the CDC's Autism and Developmental Disabilities Monitoring (ADDM) Network surveillance report. Based on standardized monitoring across multiple U.S. sites, it documents an overall autism prevalence of 32.2 per 1,000 — about 1 in 31 — among 8-year-old children, with wide variation between communities. It is the definitive reference for prevalence figures and trends in early identification.

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PREVALENCE AND EARLY IDENTIFICATION OF AUTISM SPECTRUM DISORDER AMONG CHILDREN