Prevalence (95% CIa) of ASD per 1,000 8-Year-Olds and Ratios of ASD Prevalence by SESb, Stratified by Race/Ethnicityc.

aCI = confidence interval.bSocioeconomic Status (SES) is indicated by the percentage of families with incomes above the federal poverty level who had children in the census block group of the index child, divided into population SES tertiles.cThe following differences in prevalence between ethnic group were statistically significant at pOverall: Non-Hispanic White versus Non-Hispanic Black; Non-Hispanic White versus Hispanic; Non-Hispanic Black versus Asian; and Hispanic versus Asian. In addition, the overall prevalence of ASD differs at pLow SES: Non-Hispanic White versus Non-Hispanic Black; Non-Hispanic White versus Hispanic; and Non_Hispanic White versus Asian. In addition, within the low SES stratum, the prevalence of ASD differs at pMedium SES: Non-Hispanic Black versus Hispanic.High SES: Non-Hispanic White versus Non-Hispanic Black; Non-Hispanic White versus Asian; and Hispanic versus Asian. In addition, within the high SES stratum, the prevalence of ASD differs at p