population and in certain age-gender-race groups may be significantly higher. Direct costs of disability would appear to be as high as $200 billion dollars a year and indirect costs may be as high as $155 billion. Thus, regardless of the definition of disability used, disability affects a substantial portion of the population and exacts a tremendous economic toll on the nation. In addition to diminishing or reducing disabilities due to paralysis or to visual or orthopedic impairments, rehabilitation science and engineering can contribute handsomely to enabling people to work by modifying the work environment, providing special equipment at work sites, enabling people to work at off-site locations, or providing the personal aids needed to carry out work tasks.
The foregoing data on the prevalence of and costs associated with disability were collected without an explicit conceptual model of disability. Accordingly, disability is defined in different terms for each of the major statistical series. More importantly, the design of each of these series predates the development of a more contemporary understanding of the process by which pathologies, impairments, and functional limitations give rise to disability, suggesting that the emerging definitions of disability are yet to be reflected in data collected in current surveys. In the chapter to follow, the committee reviews how the prevailing wisdom about the cause of disability has changed in the last several decades and then shows how the emergent model of disability might structure the research agenda for the foreseeable future, including the collection of data on the prevalence and impact of disability.
Recommendation 2.1 The Disability Statistics Subcommittee of the Interagency Committee on Disability should foster research to design and evaluate survey items to be used to ascertain the prevalence and impact of disability that accord with the contemporary model in which disability is jointly determined by characteristics of individuals and of their environments.
Recommendation 2.2 These survey items should be incorporated in on-going surveys, including the National Health Interview Survey, Current Population Survey, and Survey of Income and Program Participation.