Measuring Disabilities for Persons in the Labor Force
As noted in chapter 1, there is no consensus on the definition of disabilities. This means that in examining statistics related to disabilities, it is necessary to understand the definition used in
compiling the statistics.
This chapter uses three different sources for information about people with disabilities. The decennial census has two relevant questions on work-related disabilities. Individuals are considered to
have a disability if they answered "yes" to the question, "Does [the person under discussion] have a physical, mental, or other health condition that has lasted for 6 or more months and which limits the kind or amount of work [the person] can do at
a job?" or "yes" to a similar question indicating that the disability made the person unable to work. This definition is not adequate for current purposes for two reasons. First, individuals with what are usually regarded as significant
disabilities may respond that they do not have a work disability if they regard their work as being consistent with their education and other skills. This is especially important in understanding the representation of those with disabilities in
science and engineering fields, since the work is primarily intellectual. With appropriate accommodation, individuals with significant disabilities that impair their sensory functions or mobility can be highly productive and may not regard
themselves as having a disability that affects their ability to work. Second, the measure does not distinguish among types of disabilities. Some disabilities (e.g., disabilities that significantly impair mental functioning) would preclude
individuals from attaining the necessary skills for S&E employment. It is important, though not always easy, to distinguish between those with disabilities that cannot be accommodated within the S&E labor force and those with disabilities
that can be accommodated.
To address the problems with the Census Bureau's definition of disabilities, NSF's Survey of Doctorate Recipients uses a functional definition of disability patterned after one developed for a planned
survey of individuals with disabilities developed by the Census Bureau. This measure is based on asking individuals, "What is the USUAL degree of difficulty you have with [specific tasks involving seeing, hearing, walking, and lifting]. Respondents
are given five choices for each response, ranging from "none" to "unable to do." Unless elsewhere noted, having a disability is defined for this survey as having at least moderate difficulty in performing one or more of these tasks. While this
definition was designed toprovide a relatively objective measure of disability, it is important to note that not all disabilities are captured by this measure. For example, learning disabilities and behavioral disorders are not included.
The 1991-92 Survey of Income and Program Participation (SIPP) used questions for measuring disability that are quite similar to those in the Survey of Doctorate Recipients (McNeil 1993). This provides
an opportunity to make some approximate comparisons between the S&E doctoral population and the larger population.