Screening and direct assessment methodology to determine the prevalence of autism spectrum disorders.

PURPOSE: Findings from the Centers for Disease Control and Prevention-sponsored Autism and Developmental Disabilities Monitoring (ADDM) network suggest a growing prevalence of autism spectrum disorders (ASDs). The rigorous ADDM record review methodology has provided valuable insight into the epidemiology of autism spectrum disorder (ASD), but recent studies using alternative methods have reported significantly higher prevalence estimates. The South Carolina Children's Educational Surveillance Study (SUCCESS) was designed to determine ASD prevalence via population-based screening and direct assessment and to compare prevalence results to ADDM and administrative prevalence counts. This article provides an overview of the methods used for this study.

METHODS: SUCCESS involved a novel (first in the United States) population-based screening approach combined with direct assessment to determine ASD prevalence.

RESULTS: SUCCESS results will be compared to those obtained via records-based surveillance (ADDM) and administrative counts in the same population of children. This article describes the methods for developing and implementing SUCCESS and rationale for major decisions. Procedures used to maximize participation and accurately determine case status are discussed. Study results will be available in 2016.

CONCLUSIONS: Accurate reporting of ASD prevalence is important to researchers, health care providers, policy makers, and families. This study will clarify the findings of various methods used to estimate ASD prevalence.