This first section provides numbers to answer the most basic question on disability: "How many people have disabilities?"
The best estimates come from two main national surveys using different definitions of "disability."
The Survey of Income and Program Participation (SIPP) uses a definition of disability which considers limitations in specific functional activities, activities of daily living (ADLs) and instrumental acitivities of daily living (IADLs), the use of special aids, the presence of certain conditions reklated to mental functioning and the ability to work. Furthermore, the SIPP includes program participation data in its estimates.
The National Health Interview Survey (NHIS) defines disability as being limited in activity caused by chronic health conditions. It also looks at limitations in terms of major activities associated with a person's age group.
Levels of severity are presented for both surveys also. In the SIPP, an inability to perform physical functions is the measure of severity, while in the NHIS it is the need for assistance in daily activities.
These surveys are better at measuring physical limitations than mental limitations. Other data sources are presentedin this section for estimating the prevalence of mental retardation and mental disorders.
1.1. How many people have a disability?
1.2. How many people are severely limited in physical functions?
1.3. How many people need assistance in daily activities?
1.4. How many people have mental retardation?
1.5. How many people have a mental disorder?