RISP Data Bytes

Background

The number of people with IDD is called prevalence. The estimate of the number of people with IDD varies depending on how we define the disabilities. Beginning with the 2020 RISP report, we can separate out children based on the type of disability they have (developmental delay - one or more functional limitations, intellectual disability, and/or autism spectrum disorder). We include adults with intellectual disabilities and/or developmental disability - three or more substantial functional limitations.

Key Finding

In 2020, there were an estimated 8.38 million people with IDD in the U.S. Of those, 73% were children, and 27% were adults. Of the 6.1 million children with IDD, nearly half had a developmental delay, but only 11% were on state IDD agency caseloads. Most children have their needs met in school or through agencies other than the IDD agency. Of the 2.28 million adults with IDD, 44% were on state IDD agency caseloads.

Stacked bar chart showing an estimated 8.38 million people with IDD in the U.S. in 2020. Of them, 1.27 million were adults who were not on state IDD agency caseloads. Another 5.46 million were children not on state caseloads. There were 1.01 million adults on state caseloads and 644,948 children on state caseloads. — Children and Adults with IDD in the U.S. in 2020

Recommendations

Policymakers need to know how many people have IDD and how many need services. Several annual surveys ask if children have IDD but do not ask about adults. U.S. Census Bureau national surveys should ask adults if they have intellectual disabilities, autism spectrum disorders, or other developmental disabilities so we can update prevalence estimates for adults.

Data Source

Larson, S. A., Neidorf, J., Pettingell, S., & Sowers, M. (2024). Long-term supports and services for persons with intellectual or developmental disabilities: Status and trends through 2020. Minneapolis: University of Minnesota, Research and Training Center on Community Living, Institute on Community Integration.

Authors

Sheryl A. Larson, Jon Neidorf, and Brian C. Begin. The authors acknowledge the contributions by Jerry Smith, Sarah Curtner and John Smith to this product.

The RISP project gets funds from the Administration on Community Living, U.S. Department of Health and Human Services, Cooperative Agreement #90DNPA0006 with supplemental funding from the National Institutes on Disability, Independent Living and Rehabilitation Research Grant #90RTCP0011.

Abbreviations used: IDD Intellectual or Developmental Disabilities; HCBS Home and Community Based Services