Each year, the US Census Bureau undercounts the number of disabled people in the US. A proposed change to the census’s survey methods would further reduce the number of people counted, effectively halving its current estimates.

As disabled researchers, this issue hits close to home: under both the current and proposed definitions of disability, we are among the millions of Americans not counted. An accurate estimate of disabled people is critical to ensuring programs that support people with disabilities—including income supports (e.g., Supplemental Security Income), educational programs, and programs that support independent living—are allocated the federal funding they need. It also affects funding for research on disability, including emerging disabilities like Long COVID.

To develop inclusive policies and plans, policymakers need accurate information about how many people are disabled.

Currently, the Census Bureau uses a set of six questions from the American Community Survey—known as the ACS-6—to measure disability. These questions ask whether respondents experience functional limitations in hearing, vision, cognition, or walking, or difficulty with daily living activities (e.g., dressing, bathing, doing errands).

Many conditions are not captured by these functional definitions, including neurological disabilities like ADHD and autism, intellectual or developmental disabilities, psychiatric disabilities, and chronic illness like autoimmune diseases. Though some conditions have intermittent effects on people’s ability to function, this reality is not captured in the ACS language. Researchers have estimated that the current ACS-6 framework fails to identify almost 20 percent of people who identify as having a disability.

Other factors make it difficult to obtain an accurate count of the disabled population. There is still stigma associated with being disabled, and respondents may be hesitant to identify themselves as having a disability. Moreover, disability is an evolving concept. For example, Long COVID is an emerging type of disability; how it affects people and the number of people affected are only now becoming clear.

Read the full article about how the Census counts people with disabilities by Susan J. Popkin and Sarah Morriss at Urban Institute.