One of the posts from this summer stated that job descriptions are important because they set out expectations about a given position.
Specifically, descriptions are important under the ADA as well. They provide a framework to review whether an applicant with a disability is otherwise qualified to perform the job. They, then, allow the employer to consider what accommodations would be necessary for the applicant to handle the essential functions of the job. That, in turn, leads to clarity on whether accommodation would be reasonable.
The ADA has no express requirement to adopt job descriptions; however, the law requires that applicants and employees be capable of performing the essential functions of the position, with or without reasonable accommodation. When defining essential job functions, the EEOC reviews job descriptions written before an employer advertises a job opening. Thus, employers should be accurate in reflecting those essential functions, and generic wording does not provide sufficient detail when questions arise. Describing the specific tasks that a position requires allows for compliance with ADA and EEOC guidelines and a basis to defend your actions if you are questioned.