Disability insurance and workers' compensation both concern illness or injury in the context of work. These terms are sometimes (erroneously) used interchangeably, but in actuality they refer to very different concepts. Disability insurance provides benefits to an eligible claimant whose ability to work is compromised by injury or illness. The cause of the injury or illness need not be related directly or indirectly to the work setting. In contrast, workers' compensation is designed to provide financial relief to an employee who is injured or becomes ill as a direct result of work-related factors. Thus, the key issue in disability evaluations is functional capacity, while the key issue in workers' compensation evaluations is causality.

When assessing disability or workers' compensation claimants, it is critical for the evaluator ...