CDC Data on Autism

Autism Prevalence: Autism and Developmental Disabilities Monitoring (ADDM) Network

The Autism and Developmental Disabilities Monitoring (ADDM) Network is a group of programs funded by CDC to estimate the number of children with ASD and other developmental disabilities living in different areas of the United States. ADDM Network sites collect data from health and/or education records of 8-year-old children using the same methods across sites. They use these data to estimate the number of 8-year-old children identified with ASD. Community-level data are available for various communities across the United States for years 2000, 2002, 2004, 2006, 2008, 2010, 2012, 2014, 2016, and 2018.

Prevalence estimates can vary by type of data source because data are collected in different ways. Data collection methods differ across these sources, resulting in data gathered from various geographic locations, at different time points, among different age and racial/ethnic groups, and using different criteria to identify ASD. Because of these differences, findings typically vary across reported data sources, and it is not usually possible to compare findings.

Reported ASD Prevalence has Changed Over Time

The reported prevalence of ASD has been higher in recent years, and this trend is consistent across data sources. It is unclear how much this is due to changes to the clinical definition of ASD (which may include more people than previous definitions) and better efforts to diagnose ASD (which would identify people with ASD who were not previously identified). However, a true change in the number of people with ASD is possible and could be due to a combination of factors. Choose a data source below to see how prevalence estimates have changed over time.

Note: Hover your mouse over data points above to show prevalence by year.

ADDM Network data only represent a selection of sites within states (but not entire states) that were funded during each project cycle; therefore, data are not available for the entire United States.

**ADDM estimate = the total for all sites combined.

Reported ASD Prevalence has Changed Over Time

The reported prevalence of ASD has been higher in recent years, and this trend is consistent across data sources. It is unclear how much this is due to changes to the clinical definition of ASD (which may include more people than previous definitions) and better efforts to diagnose ASD (which would identify people with ASD who were not previously identified). However, a true change in the number of people with ASD is possible and could be due to a combination of factors. Choose a data source below to see how prevalence estimates have changed over time.

Note: Hover your mouse over data points above to show prevalence by year.

ADDM Network data only represent a selection of sites within states (but not entire states) that were funded during each project cycle; therefore, data are not available for the entire United States.

**ADDM estimate = the total for all sites combined.

Reported ASD Prevalence Varies by Sex

Since the first ADDM reporting period (2000), ASD prevalence has been higher among boys than girls across all ADDM sites. There are no clear explanations for this difference. One consideration is that boys may be at greater risk for developing ASD. Another consideration is that ASD can have different signs and symptoms in boys versus girls. This can contribute to differences in how ASD is identified, diagnosed, and reported. Choose the data source below to see how prevalence estimates vary by sex.
For every 1 GIRL, 4.1 BOYS were identified with ASD.

Reported ASD Prevalence Varies by Ethnicity

Over time, ADDM reports have consistently noted that more non-Hispanic white children are identified with ASD than non-Hispanic black or Hispanic children. Previous studies have shown that potential barriers to identification of children with ASD, especially among Hispanic children, include
 . Stigma,
 . Lack of access to healthcare services due to non-citizenship or low-income, and
 . Non-English primary language.

A difference in identifying non-Hispanic black and Hispanic children with ASD as compared to non-Hispanic white children with ASD means that some children with ASD may not be receiving the services they need to reach their full potential.
As of 2018, the ADDM Network found no overall difference in the percent of Black, White, Hispanic, and Asian or Pacific Islander 8-year-old children identified with ASD. However, at several sites, the percent of Hispanic children identified with ASD was lower compared with Black or White children. The decreasing racial and ethnic differences over time may be due to more effective outreach directed toward minority communities and efforts to have all children screened for ASD.
Choose the data source below and see how prevalence estimates vary by race/ethnicity.