Prevalence of Autism spectrum disorder and Intellectual and developmental disabilities

Autism Spectrum Disorder Prevalence

The Early Intervention program area provides widely-quoted data on the prevalence of Intellectual and Developmental Disabilities (IDD) and Autism Spectrum Disorder (ASD) that help policymakers, schools, and the public understand the scope of public resources that are and will be needed both in the early years and across the lifespan. Rigorous review and abstraction of records from pediatric health clinics, special education departments in schools, and programs specializing in developmental disabilities form the basis of the ASD prevalence work. Responding to Minnesota’s significant population growth in culturally and linguistically diverse communities -- including the nation’s largest East African Somali population -- this program area also measures the prevalence of ASD in Somali, Hmong, Latino, and other communities. 

ASD is a developmental disability that results from differences in how the brain functions. People with ASD may communicate, interact, behave, and learn in different ways. Signs of ASD begin during the early childhood years and usually last throughout a person’s life.

The term “spectrum” in ASD means that each person can be affected in different ways, and symptoms of ASD can range from mild to severe. People with ASD share some similar symptoms, such as difficulties with social interaction, difficulties with communication, and highly-focused interests and/or repetitive activities. How the symptoms affect a person’s functioning depends on the severity and combination of those symptoms.

Intellectual and Developmental Disabilities Prevalence

ICI’s nationally-significant, longitudinal studies measuring the long-term use of services for people with IDD documented the dramatic shift after 1977 of people with IDD moving out of institutional settings and into community life. In 1977, there were 327 state-operated IDD facilities serving 16 or more people in the United States. By 2016, the number had dropped to 140. In Minnesota, all of them had closed. This focus area also produces IDD policy and case studies, literature and data reviews, and trend reports. 

The U.S. Census Bureau reported that there were 73.6 million children 17 years or younger and 249.5 million adults ages 18 years or older in the United States in 2016. Applying the prevalence rate of 69.9 per 1,000 for children from the 2016 NHIS and 7.9 per 1,000 for adults from the 1994/1995 NHIS-D, we estimate there were 5,147,596 children, and 1,970,933 adults with IDD in the 2016 U.S. civilian noninstitutionalized population. An additional 255,873 people with IDD of all ages lived in congregate settings of four or more people, nursing homes, or psychiatric facilities on June 30, 2016. In total, we estimate that there were 7,374,402 people with IDD in the U.S. in 2016 (22.8 per 1,000).

For more information on IDD prevalence data, visit