Why is data on people with disabilities in science and engineering scarce?

DO-IT Factsheet #366
http://www.washington.edu/doit/Stem/articles?366

According to the National Center for Science and Engineering Statistics [1], National Science Foundation (NSF), the data available on people with disabilities in science and engineering is seriously limited for the following reasons.

For these reasons, even when there is considerable information available about the number of individuals with disabilities in the education system and in the science and engineering workforce, it is often impossible to develop accurate comparison figures. For data on people with disabilities and science and engineering consult the Women, Minorities, and Persons with Disabilities in Science and Engineering [2] publication on the NSF website.

References