The ADA blurs the traditional distinction between the medical determination of a functional impairment and the legal determination of the disability resulting from that impairment. In addition to disability determinations under the ADA, physicians are routinely asked to make functional impairment determinations for workers’ compensation claims and for civil litigation arising from nonworkplace injuries. The physician’s role is to determine the patient’s loss of function in the affected organ system. The insurance company, court, or administrative agency providing the compensation decides how much of a disability this limitation of function constitutes. A disability may be caused by either illness or injury. The etiology of the illness or injury may determine how the patient will be compensated for the disability but is not important to the evaluation of the extent of the disability. For the purpose of the medical evaluation, it does not matter whether the patient is injured on the job or playing football on the weekend.

For instance, a physician may determine that a patient has lost 20% of the range of motion in his right hand. This determination is unrelated to the patient’s occupation. The extent of disability caused by a functional impairment is a job-specific determination. For a manual laborer or an attorney, this loss of range of motion may not constitute a disability. The patient is able to pursue his usual occupation with little or no difficulty, and there is no substantial limitation on household tasks. If the patient is a concert pianist or a surgeon, this 20% loss of range of motion may constitute a total disability from his chosen work.

The severity of the workplace disability is not directly related to the extent of functional impairment or disability in personal living. A telephone operator who is blinded is severely disabled in his or her personal life but may not be occupationally disabled. A stevedore with a back injury may have little handicap in day-to-day living but be totally and permanently disabled regarding this work. In an evaluation of disability under the ADA or Social Security, the focus is on alternative related employment. The proposed rules discuss the example of a surgeon with a mild palsy. Although the surgeon may be disqualified from performing surgery, he or she may be employed in other medical activities and is thus not disabled. This is consistent with a policy that encourages full employment. Conflicts arise because a person making a tort or workers’ compensation claim wants to be found maximally disabled, whereas a person claiming under ADA does not want to be found to be unqualified for a given job.