CODI: Cornucopia of Disability Information
Americans with Disabilities: Introduction
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This report presents data on the disability status of the noninstitutional population of the United States. The source of the data is a combined sample from the 1990 and 1991 panels of the Survey of Income and Program Participation (SIPP). A topical module (or supplement) containing an extensive set of questions about disability status was asked as part of the sixth wave of the 1990 panel and the third wave of the 1991 panel. Both of these waves were in the field during the last 3 months of 1991 and the first month of 1992. The total sample size for this study was approximately 30,000 interviewed households. Estimation procedures were used to inflate weighted sample results to independent estimates of the civilian noninstitutional population of the United States.
All demographic surveys, including SIPP, suffer from undercoverage of the population. This undercoverage results from missed housing units and missed persons within sample households. Compared to the level of the 1980 decennial census, overall undercoverage is about 7 percent. Undercoverage varies with age, sex, and race. For some groups, such as 20 to 24 year old Black males, the undercoverage is as high as 35 percent. The weighting procedures used by the Census Bureau partially correct for the bias due to undercoverage. How- ever, its final impact on estimates is unknown. For details, see appendix B.
The term "disability" can be defined narrowly or broadly depending on the interest of the analyst. An example of a narrow definition is found in the Social Security Disability Insurance Program (SSDI). Under this program, persons are considered disabled if they are "unable to engage in substantial gainful activity." The disability determination process under the SSDI recognizes that medical conditions are not the only factors that affect work disability and takes into consideration other factors including age, education, and work history. A broader definition of disability is found in the Americans With Disabilities Act of 1990 (ADA). Under the ADA, an individual is considered to have a disability if the person: (a) has a physical or mental impairment that substantially limits one or more of the major life activities; (b) has a record of such an impairment; or (c) is regarded as having such as impairment. The definitions above and the disability statistics that are presented in this report can be better understood by placing them in a conceptual framework. Perhaps the most important work in the area of a conceptual framework for disability is that of Saad Nagi. Nagi's framework consists of four interrelated concepts: active pathology, impairment, functional limitation, and disability. Nagi's framework was restated in the 1991 report Disability in America, edited by Andrew Pope and Alvin Tarlov.
1. Active pathology involves an interference with normal processes and the simultaneous efforts of the organism to regain a normal state.
2. Impairment involves a loss or abnormality of an anatomical, physiological, mental or emotional nature. Impairments include: (a) all conditions of pathology; (b) residual losses or abnormalities following an active state of pathology; and (c) abnormalities not associated with pathology (congenital formations).
3. Functional limitations refer to limitations which are manifested at the level of the organism as a whole (e.g., seeing, hearing, reaching, walking, performing basic mental tasks).
4. Disability refers to limitations in performing socially defined roles and tasks in such spheres as interpersonal relationships, family life, education, recreation, self-care, and work.
A second conceptual framework has been developed by Philip Wood for the World Health Organization as part of the International Classification of Impairments, Disabilities, and Handicaps (ICIDH). The ICIDH was developed as an extension of the International Classification of Diseases (ICD) and provides a detailed classification system for three concepts: impairments, disabilities, and handicaps. The ICIDH is not a finished system and a considerable amount of work is currently being devoted to improving certain aspects of the system especially the handicap concept and the classification of handicaps. Under the ICIDH, impairments are concerned with abnormalities of body structure, organ or system function, and appearance; disabilities reflect the consequences of the impairment in terms of functional performance; and handicaps are concerned with the disadvantages experienced by an individual as a result of impairments and disabilities and the interaction of the individual with his or her surroundings.
A recent report examined the applications of the ICIDH to household disability surveys and proposed a recommended minimum set of questions for such surveys. The recommended set is actually very close to the questions that are described as functional limitation questions in this study [McNeil, 1991a].
The SIPP questions that were used to determine disability status for this study can be grouped into 12 categories (questions in categories 1-11 are reproduced in appendix C):
1. Questions for persons 15 years old and over about the use of special aids: canes, crutches, walkers, and wheelchairs.
2. Questions for persons 15 years old and over about difficulty with sensory and physical functional activties: seeing, hearing, having one's speech understood, lifting and carrying, walking up a flight of stairs, and walking a quarter of a mile. When a person was identified as having difficulty with a particular functional activity, a follow-up question asked if the person could perform the activity at all.
3. Questions for persons 15 years old'and over about difficulty with Activities of Daily Living (ADL's): getting around inside the home, getting in or out of a bed or chair, taking a bath or shower, dressing, eating, and using the toilet. When a person was identified as having difficulty with a particular ADL, a follow-up question asked if the person needed the help of another person with that activity.
4. Questions for persons 15 years old and over about difficulty with Instrumental Activities of Daily Living (IADL's): going outside the home, keeping track of money or bills, preparing meals, doing light housework, and using the telephone. For the first four IADL's, a follow-up question about the need for personal assistance was asked when a person was identified as having difficulty with that activity. When a person was identified as having difficulty using the telephone, a follow-up question asked if the person was able to use the telephone at all.
5. Questions for persons 15 years old and over about the existence of specific conditions including: (a) dyslexia; (b) mental retardation; (c) developmental disabilities such as autism or cerebral palsy; (d) Alzheimer's disease, senility, or dementia; and (e) any other mental or emotional condition.
6. A question for persons 16 to 67 years old about the presence of a physical, mental, or other health condition that limits the kind or amount of work the person can do. When a person was identified as having a work disability, a follow-up question asked if the person was prevented from working at a job or business.
7. A question for persons 16 years old and over about the presence of a physical, mental, or other health condition that limits the kind or amount of housework the person can do. When a person was identified as having a housework disability, a follow-up question asked if the person was prevented from doing work around the house.
8. A question asked of parents of children under 6 years about whether the children had any limitations at all in the usual kind of activities done by most children their age.
9. A question asked of parents of children under 6 years about whether the children had received therapy or diagnostic services designed to meet their developmental needs.
10. A question asked of parents of children 6 to 21 years old about whether the children had limitations in their ability to do regular school work.
11. A question asked of parents of children 3 to 14 years old about whether the children had a long lasting condition that limited their ability to walk, run, or use stairs.
12. Questions which identified persons who were receiving Supplemental Security Income or Medicare benefits on the basis of their disability status.
In terms of Nagi's conceptual framework, categories 1, 2, and 11 are measures of functional limitations; categories 3, 4, and 7 are measures of self-care or family life disabilities; categories 6 and 12 are measures of work disability; category 10 is a measure of education disability; categories 8 and 9 are measures of disability for young children; and category 5 is a measure of the presence of specific impairments.
When a person was identified as having a physical functional limitation or an ADL or IADL limitation, a follow-up question asked the respondent to examine a printed list of conditions and select the condition or set of conditions that caused the limitation. The condition question was also asked for persons identified as having a work or housework disability. A similar follow-up question, with a different conditions list, was asked of parents of children identified as having a limitation or disability.
For the purpose of this study, a person was considered to have a disability if the person was identified by any of the questions described in the 12 categories above (except that persons who used a cane, crutches, or a walker, but who had used such an aid for less than 6 months and who were not identified by any other item were not considered to have a disability). The category of persons with a severe disability includes the following:
1. Persons 15 years old and over who used a wheelchair or who had used a cane, crutches, or a walker for 6 months or longer.
2. Persons 15 years old and over who were unable to perform one or more functional activities or who needed the help of another person with an ADL or an IADL.
3. Persons 16 to 67 years old who were prevented from working at a job or business.
4. Persons 16 years old and over who were prevented from doing work around the house.
5. Persons 15 years old and over with mental retardation, a developmental disability such as autism or cerebral palsy, or Alzheimer's disease, senility, or dementia (either measured directly or cited as a condition causing a limitation or disability).
6. Persons 0 to 21 years old with autism, cerebral palsy, or mental retardation (cited as a condition causing a limitation or disability).