NIDRR's Long Range Plan

Policy issues at the forefront of the disability agenda require accurate data, routinely repeated measures, sophisticated analysis, and broad dissemination.

This chapter of the Plan presents NIDRR’s operative definitions of disability, discusses several analytical frameworks for categorizing disability, and highlights deficits in current definitions and data collection. The chapter then presents data about the prevalence and distribution of disability in the nation and includes selected demographic data related to the major NIDRR goals of independence, inclusion, and employment.

Definitions and Concepts of Disability and Disablement

The definition of an individual with a disability under which NIDRR operates is contained in the Rehabilitation Act of 1973, (Public Law 93-112) as amended. The law describes a person with a disability as follows:

This definition is similar to those contained in the ADA, the Assistive Technology Act of 1998, and the Technology-Related Assistance for Individuals with Disabilities Act (Tech Act).

The impairments that cause limitations in activities may relate to genetic conditions or to acquired diseases or traumas. The extent of a disability and the conditions associated with a disability are significant to individuals, to families, and to the nation.

Prevailing definitions, based in statute and supporting program authorities, clearly do not reflect new paradigm concepts of disability. Nearly all definitions identify an individual as disabled based on a physical or mental impairment that limits the person’s ability to perform an important activity. Note that the other possibility—that the individual is limited by a barrier in society or the environment—is never considered. This plan suggests that it is useful to regard an individual with a disability as a person who has an impairment that requires an accommodation or intervention rather than as a person who is limited solely by a condition. This new approach derives from the interaction between personal variables and environmental conditions. Because accommodations can address person-centered factors as well as socioenvironmental factors, a need for accommodation is a more adaptable concept for the new paradigm.

The various definitions of disability that have formed the basis for both program eligibility and survey data collection do not have explanatory power for research purposes. The field of disability research lacks a widely accepted conceptual foundation to measure it as well as consistent definitions for data collection. In recent years, however, a number of efforts to develop conceptual frameworks to organize information about disability have been initiated (see table 2).

Table 2. - Concepts in Models of Disability
ICIDH Nagi/1991 IOM NCMRR

Disease--Something abnormal within the individual; etiology gives rise to change in structure and functioning of the body. Active pathology--Interruption or interference of normal bodily processes or structure. Pathophysiology--Interruption or interference with normal physiological and developmental processes or structure.

Impairments--Any loss or abnormality of psychological, physiological, or anatomical structure or function at the organ level. Impairment--Anatomical, physiological, mental or emotional abnormalities or loss. Impairment--Losses or abnormalities of cognitive, emotional, physiological, or anatomical structure or function, including losses or abnormalities that are not those attributable to the initial pathophysiology.

Disability--Any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being. Functional limitation--Restriction or lack of ability to perform an action or activity in the manner or range considered normal – which results from an impairment. Functional limitation--A restriction or lack of ability to perform an action in the manner or within the range consistent with the parts of an organ or organ system.

Handicap--A disadvantage resulting from an impairment or disability that limits or prevents fulfillment of a role comsidered normal for a particular age, sex, and sociocultural factors. Disability--An inability or limitation in performing socially defined activities and roles expected of individuals within a social and physical environment. Disability--An inability or limitation in performing tasks, activities, and roles to levels expected within the physical and social context.

Societal limitation--Restrictions attributable to social policy and barriers (structural or attitudinal) which limits fulfillment of roles and denies access opportunities that are associated with full participation in society.

Note: Information in column 1 is from International Classification of Impairments, Disabilities, and Handicaps, by the World Health Organization, 1980, Geneva, Switzerland: World Health Organization.
Information in column 2 is from Disability Concepts Revisited: Implications for Prevention, by S.Z. Nagi, 1991, (p. 7) in Disability in America: Toward a National Agenda for Prevention by A. M. Pope and A. R. Tarlov (Eds.), 1991, Washington, DC: National Academy Press.

Information in column 3 is from Research Plan for the National Center for Medical Rehabilitation Research, (p. 33), by the National Institute of Child Health and Human Development (1993) (NIH Publication No. 93-3509), Washington, DC: U.S. Government Printing Office.

Continuum of Enablement––Disablement

The most widely used conceptual frameworks applied to disability and rehabilitation research share a continuum that progresses from some underlying etiology or disease to limitations in physical or mental function. These functional limitations, when combined with external or environmental conditions, may lead to some deficit in the performance of daily activities or expected social roles.

In Enabling America, the IOM urges the adoption of a new conceptual framework as a model for the enablement-disablement process (Brandt & Pope). This model has the advantage of identifying components of person-centered and environment-centered variables. The IOM framework identifies four categories of individual factors (person, biology, behavior, and resources) and nine categories of external environment factors (natural, culture, engineered environments, therapeutic modalities, health care delivery system, social institutions, macro-economy, policy and law, and resources and opportunities).

NIDRR research focuses on crucial areas of functional loss, disability, and socioenvironmental aspects of the continuum. In keeping with the new paradigm, NIDRR emphasizes the importance of explicating the connection between the person and the environment, an interface that determines the disabling consequences of impairments and related conditions. This study of the dynamic interaction among various individual and environmental variables requires NIDRR to increase its attention to shaping the structure, management, and capacity for research. Methodologies are needed, often in an interdisciplinary context, that can illuminate multiple facets of disablement and enablement from numerous perspectives.

Limitations in Federal Data Sources

The various federal data collection efforts that assess the extent and distribution of disability in society are less than ideal for measuring the population that meets the NIDRR definition of an individual with a disability. These efforts generally can be categorized as one of two types (1) program data, which focus on the recipients of federal benefit or service programs, or (2) national surveys that focus on perceived limitations in activities caused by health conditions. Both program and survey data focus on the physical or mental impairment as the cause of the limitation. This is a reductionist approach that discounts social and environmental factors or assumes that these factors are subsumed within individual attributes.

The National Health Interview Survey (NHIS) and the Survey of Income and Program Participation (SIPP) are the two most widely used sources of survey data to describe the population of individuals with disabilities. Researchers currently are analyzing data from the Disability Supplement to the NHIS; these analyses will yield much-needed information on people with disabilities. The development of the Disability Supplement was a collaborative effort by federal agencies concerned with disability issues. While the Disability Supplement data have enormous value, the supplement, like other data sources, doesn’t measure the environmental factors (social or physical) that contribute to disabilities, nor the interaction between the person and his or her environment.

Federal data collection efforts––including the Census, the NHIS, the SIPP, the Current Population Survey (CPS), and many other program-specific or topical data collection methods––not only fail to address important new concepts of disability, but also are limited in other ways. The sampling procedures may result in the exclusion of low-incidence disabilities and insufficient information about minority populations; self-reporting leads to underreporting many conditions; and survey formats frequently are inaccessible to people with cognitive, sensory, or language limitations. Many federal data collection efforts, as well as most private ones, do not routinely include information about people with disabilities in their data collection and reporting. Improving data quality and availability will be a key goal of NIDRR over the next five years.

Particular problems exist in defining and quantifying disability in children. Many service program staff rely on diagnostic categories for eligibility, and even those who have attempted a functional approach have had difficulty assessing the effect of context, expectations, transactions with adults, chronicity, and duration in determining the extent of disability among children.

The Office of Special Education Programs (OSEP) administers the Individuals with Disabilities Education Act (IDEA). A U.S. Department of Education effort, IDEA mandates that schools have the full range of services necessary to provide a free and appropriate public education for children with disabilities. According to OSEP’s 1995-96 IDEA annual report to Congress, 5.6 million disabled children (ages 3 to 21) received educational services. Approximately one-half of these children were identified as having specific learning disabilities. Other high-incidence disabilities included speech and language impairments, mental retardation, and serious emotional disturbances.

Because OSEP and other Department of Education offices focus their research on activities based in the educational system––including the development of curricula and teaching methods, as well as teacher training––NIDRR has concentrated its research on other areas concerning disabled children. These issues include family-child relations, social relationships, community integration, medical technologies that may replace or substitute for function, accommodations, and support available to families. NIDRR research also has a role in addressing the critical problems of succeeding in the transition from school to adult life in the community, to work, and to adult service systems. In a broader context, it is important to note that 5.5 percent of all American families have one or more children with a disability (LaPlante, Carlson, Kaye, & Wenger). Children with disabilities are more likely to live in low-income families and in families headed by single mothers.

Prevalence of Disability

Disability research is very important due to the fact that disabilities are so frequent and widespread in the United States. The following data about disabilities were selected because of their relevance to NIDRR’s specific priorities and to the overall objectives of this Plan.

The 1994 NHIS estimated that 15 percent of the noninstitutionalized civilian population—some 38 million people—were limited in activity due to chronic conditions (Adams & Marano 1995). The Institute of Medicine interpolated the NHIS data to indicate that 38 percent of disabilities were associated with mobility limitations, followed by chronic disease (32 percent); sensory limitations (8 percent); intellectual limitations (7 percent); and other conditions (15 percent) (Pope & Tarlov 1991). The SIPP identified 48.9 million people who reported themselves as limited in performing functional activities or in fulfilling a socially defined role or task. Of these, 24.1 million people were identified as having a "severe disability" (Kraus, Stoddard, & Gilmartin 1996). Both surveys excluded people in nursing homes or institutions, who would be expected to have a high rate of disability. Including that population through extrapolation has led to the commonly cited figures of 43 million to 48 million Americans with disabilities.

Both the NHIS and SIPP focus on limitations in performing major life activities that are due to a physical or mental condition. Both groups also provide data, however, on people who are limited in performing or unable to perform activities of daily living (ADLs)—such as eating, bathing, dressing, toileting, or moving around without assistance from others or the use of devices. Data are also collected on those who have trouble with instrumental activities of daily living (IADLs)––such as performing basic home care, shopping, preparing meals, telephoning, and managing money. Approximately 8 million people reported having difficulty with ADLs, and some 4 million of them said they needed the assistance of another person (McNeil 1993).

The range of these estimates—from approximately 4 million people who need help simply to sustain their lives to the 40 million who report any kind of activity limitation—illustrates the risks in discussing the disabled population as a homogeneous group. More refined data are needed to assess the needs for medical and health care, vocational rehabilitation and employment assistance, supports for living in the community, and assistive technology.

Demographics of Disability: Age, Gender, Race, Education, Income, and Geography

Disability is distributed in many ways throughout the population, according to characteristics such as age, gender, race, ethnicity, and both the region and size of the locality in which a person resides. The educational level is inversely correlated with the prevalence of disability. Poverty is a key factor, both as a contributing cause and a result of disability. Table 3 presents NHIS data on sociodemographic correlates of activity limitations. These data indicate that disability is very likely linked to other social factors, reinforcing the need to address disability in a broad context.

Emerging Universe of Disability

NIDRR has begun to focus on an emerging universe of disability, in which the conditions associated with disability, their distribution in the population, and their causes and consequences are substantially different from those in the traditional disability population.

This emerging universe is identified with new disabling conditions; new causes for impairments; differential distributions within the population; increased frequency of some impairments; and different consequences of disability. Such consequences relate to social-environmental factors, lifespan issues, and projected demands for services and supports.

Researchers have identified a new morbidity (Baumeister, Kupstas & Woodley-Zanthos 1993) in which the cluster of factors associated with poverty—such as poor education, poor medical care, babies with a low birth weight, a lack of prenatal care, substance abuse, interpersonal violence, isolation, occupational risks, and exposure to environmental hazards—have a high correlation with the existence of impairments, disabilities, and exacerbated consequences of disabilities.

For example, the leading cause of mental retardation is no longer RH-factor incompatibility, but may be related to any factor associated with high-risk births, which are more common among low-income mothers. Interpersonal violence accounts for the rising incidence of certain conditions, especially spinal cord injury and traumatic brain injury, among inner-city minority populations. These developments have enormous implications for research problems to be addressed and for future demands for various types of services.

New illnesses or conditions have emerged in recent years; some, but by no means all, are poverty-related. AIDS, Attention Deficit Hyperactivity Disorder (ADHD), violence-induced neurological damage, repetitive motion syndrome, chronic fatigue syndrome, childhood asthma, drug addiction, and environmental illnesses are all either relatively new conditions or ones of increasing prevalence and severity in society. Additionally, the aging of the population, given the higher rates of many disabilities among older people, is another demographic factor that will influence issues to be addressed by applied research. Many emergent disabilities, including those attributed to violence, abuse, and poverty, have a higher incidence among women and are particularly likely to affect women who already have disabilities.

As new causes of disabilities emerge, the new paradigm of disability clearly provides a progressive approach to successfully addressing environmental and social barriers for people with disabilities. These new issues have implications not only for disability research and services, but also for public health and prevention activities.

Disability, Employment, and Independent Living

Because of NIDRR’s statutory concern with improving employment outcomes for people with disabilities, it is valuable to present a brief overview of the employment status of people with disabilities.

LaPlante & Carlson (1996) reported that 19 million Americans (ages 18 to 69) with an impairment or health problem were unable to work or were limited in the amount or type of work they could perform. According to the CPS, about 10 percent of the population between ages 16 and 64 had work limitations (different age ranges reflect changing concepts of working age) (LaPlante, Kennedy, Kaye, & Wenger 1996). Back disorders, heart disease, and arthritis were frequently reported as major causes of work disability (LaPlante & Carlson 1996). However, mental illness is one of the most work-disabling conditions; data have shown that among adults with a serious mental illness (an estimated 3.3 million people), 29 percent are unable to work, and 18 percent are limited in their ability to work (Barker, Manderscheid, Hendershot, Jack, Schoenborn, & Goldstrom 1992).

While the presence of any disability reduces the likelihood of employment, the effect is closely tied to the severity of the disability. The SIPP estimates that among people 21 to 64 years of age, the employment rate was 81 percent for people with no disability, 67 percent for people with a disability that was not severe, and 23 percent for people with a severe disability (McNeil 1993). Only 21 percent of people needing personal assistance with ADLs or IADLs were employed (U.S. Bureau of the Census 1998). The unemployment rate for people with disabilities, which counts only those people in the labor force, was 12.6 percent, more than twice the unemployment rate of nondisabled Americans (Stoddard, Jans, Ripple, & Kraus 1998).

Disabled people who work full-time typically earn less than nondisabled workers, with the earnings gap widening with age and the severity of the disability. People with disabilities who do not work may qualify for income support payments under Social Security Disability Insurance (SSDI) (if they have a work history) or Supplemental Security Income (SSI). As of January 1996, 5 million people received SSDI benefits, including 4.2 million disabled workers; 686,300 disabled adult children; and 173,800 disabled widows and widowers (Social Security Administration 1996). A 1993 report cited mental disorders as the most frequent cause of disability (35 percent), followed by musculoskeletal, circulatory, and nervous system disorders (Social Security Administration 1993).

At the end of 1993, about 3.8 million people under age 65 received SSI benefits due to disability and poverty (Kochhar & Scott 1995). More than one-half of these people had either mental retardation or mental illness. The Social Security Administration (SSA) has noted a sharp increase in the number of disabled SSI recipients, an increasing proportion with mental illness, and a growing number who enter the rolls as children and remain for long periods (Kochhar & Scott 1995).

Many of these increases in the numbers of SSDI and SSI recipients can be attributed to the following: changing the program (such as initiating different eligibility requirements and outreach), shifting from other income support categories, changing the stability of employment and private health insurance, and bundling of health insurance coverage with income supports. Eligibility for public health insurance is generally tied to the receipt of income transfer payments from a public income support program.

Data elements about residential status, family composition, and the need for personal assistance services illuminate some of the characteristics of the disabled population. Of the estimated 48.9 million people with disabilities from the SIPP data, 32.5 million own their own homes and 16.4 million rent (McNeil 1993). An estimated 9.8 million live alone, and more than 27 million people with disabilities are married. An estimated 8.3 million individuals with disabilities live in a household with their spouse and children under age 18, while an estimated 1.9 million are single parents with disabilities.

An estimated 20.3 million families, or 29.2 percent of all 69.6 million families in the United States, have at least one relative with a disability (as measured by having an activity limitation). This rate for families is much higher than the rate for individuals having a disability. Further, there appears to be a clustering of people with disabilities in families and households, with a much higher-than-expected likelihood of both adult partners having disabilities and a greater-than-average chance that children with disabilities will live with one or more parents with disabilities. Families headed by adults with disabilities are more likely to live in poverty or to be dependent on public income support programs.

Conclusion

This chapter of the Long-Range Plan highlighted some important disability statistics that illustrate the scope of disability in the United States. Throughout the Plan, significant data also are interspersed about the use of assistive technology, access to health care, labor force participation, and community living. In addition, Chapter 7 addresses the need for future research in disability data collection.

Overall, the current data on disabilities provide both a picture for concern and a cause for optimism. People with disabilities tend to have lower-than-average educational levels, low income levels and high unemployment rates, especially people with severe disabilities. Moreover, the relationship between disability and poverty tends to be bi-directional, with the conditions of poverty creating a high risk for disability and disability itself leading to poverty.

At the same time, it is clear that more individuals with disabilities are completing high school and college, and education is closely correlated with employment and independence. Increasingly, individuals with disabilities are living in the community, marrying, and raising families. These individuals may receive increased attention from businesses as they constitute a market for accessible housing and adaptive devices, recreation, adult education, accommodated travel, health care, and other services.

Providers of goods and services in the marketplace—whether purveyors of travel and recreation, assistive devices, clothing, or any other commodities—want estimates of the size and characteristics of the potential disability market for their products. It is becoming increasingly important to provide these market estimates and to package data to meet the needs of manufacturers and distributors, so businesses can expand the variety of goods and services available to people with disabilities.

It is also true that, while the presence of a disability may present significant challenges to individuals and families, society demonstrates a growing capacity to assist people with disabilities to meet their needs for equity and access through new discoveries in research, improved service methods, and informed policy decisions.

Section One: Background

Chapter 2: DIMENSIONS OF DISABILITY

Definitions and Concepts of Disability and Disablement

Continuum of Enablement––Disablement

Limitations in Federal Data Sources

Prevalence of Disability

Demographics of Disability: Age, Gender, Race, Education, Income, and Geography

Emerging Universe of Disability

Disability, Employment, and Independent Living

Conclusion