The Americans With Disabilities Act (ADA) requires employers to base job-related decisions on a person’s ability to perform essential job functions under reasonable accommodations. Job descriptions must specify these essential functions, and employment decisions should be made accordingly. Non-essential functions are considered marginal and should not be used as a basis for employment decisions. Both essential and marginal functions must be clearly defined in job descriptions.
An essential function is a fundamental duty or responsibility that is critical to the job, while a marginal function is relatively less important to the job’s purpose. An essential function cannot or should not be delegated to others, but a marginal function, while desirable to include in the job, can be assigned to another position without significant issues.
A marginal function may be important to the overall work unit, but it is not essential for a specific job. It must still be completed, but it can be handled by another employee or position.
An article by P.C. Grant in Business Horizons (March-April 1997), titled “Essential or marginal? Job functions and the Americans with Disabilities Act,” provides valuable insights into this matter.
Let’s consider a job that involves operating a machine. The job description mentions “painting the machine twice a month.” However, this task is not critical to the job’s execution. “Operating the machine” is the essential function, so it is listed as such. “Painting the machine” is a marginal function because it’s not vital to job performance. Reassigning the “painting the machine” task would not impact the job description for “Machine Operators.”