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 in 2020, we separated out children based on the type of disability they have (developmental delay with one or more functional limitation, intellectual disability, and/or autism spectrum disorder). We include adults with intellectual disabilities and/or developmental disability with three or more substantial functional limitations.

Key Finding

In 2021, there were an estimated 8.56 million people with IDD in the US. Of those, 73% were children and 26% were adults. Of the 6.31 million children with IDD, half had a developmental delay, but only 10% were on state IDD agency caseloads. Most children have their needs met in school or through agencies other than the IDD agency, Of the 2.25 million adults with IDD, 48% were on state IDD agency caseloads.

Infographic with silhouettes of people. The figures represent the 8.56 million people with intellectual and developmental disabilities in the U.S. in 2021. The top three rows are dark blue and represent 3.69 million children in the U.S. that have a developmental delay but not an intellectual disability or autism spectrum disorder (ASD). The two rows in the middle are teal and represent 2.62 million children in the U.S. that have an intellectual disability or ASD. The bottom two rows are yellow and represent 2.25 million adults in the U.S. with an intellectual and/or developmental disability. A red box is drawn around some of the figures representing 24% of children and 48% of adults with IDD known to state IDD agencies. — People with IDD in the United States

Recommendations

Policy makers 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. US Census Bureau national surveys should adults if they have intellectual disabilities, autism spectrum disorder, or other developmental disabilities so we can update prevalence estimates for adults.

Data Source

Larson, S. A., Neidorf, J., Pettingell, S., & Sowers, M. (2024). (Forthcoming). Long-term supports and services for persons with intellectual or developmental disabilities: Status and trends through 2021. Minneapolis: University of Minnesota, Research and Training Center on Community Living, Institute on Community Integration.

Authors

Data Byte Authors: Sheryl A. Larson and Jon Neidorf.

RISP is funded through a cooperative agreement 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 #90RTP0011.

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