29 CFR Part 1630, Regulations to Implement the Equal Employment Provisions of the ADA (Title I Regulations with amendments issued through May 2016)

(v) The comparison of an individual's performance of a major life activity to the performance of the same major life activity by most people in the general population usually will not require scientific, medical, or statistical analysis. Nothing in this paragraph is intended, however, to prohibit the presentation of scientific, medical, or statistical evidence to make such a comparison where appropriate.