The ADA defines “qualified” to mean a person who meets legitimate skill, experience, education, or other requirements of an employment position that she/he holds or seeks, and who can perform the essential functions of the position with or without reasonable accommodation.
Requiring the ability to perform “essential” functions assures that an individual with a disability will not be considered unqualified simply because of an inability to perform marginal or incidental job functions. If the individual is qualified to perform essential job functions except for limitations caused by a disability, the employer must consider whether the individual could perform these functions with a reasonable accommodation.
If a written job description has been prepared in advance of advertising or interviewing applicants for a job, this will be considered as evidence, although not conclusive evidence, of the essential functions of the job.
Employers are free to select the most qualified applicant available and to make decisions based on reasons unrelated to a disability.