ADA & Disabilities

ADA: Who Determines the Essential Functions of a Job?

An employee with a disability must demonstrate that he is able to perform the essential functions of his job, with or without reasonable accommodations, in order to be protected by the Americans with Disabilities Act (ADA). But what exactly does “essential functions” mean? What are the essential functions of a particular job, and who determines which functions are essential?


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The U.S. 10th Circuit Court of Appeals—which covers Colorado, Kansas, New Mexico, Oklahoma, Utah, and Wyoming—recently weighed in on this issue in a decision reversing a trial court’s dismissal of an employee’s complaint.

An Oklahoma employee alleged that he suffered discrimination based on his disability in violation of the ADA because an employer failed to hire him even though he had shown he could perform the essential functions of the job.

The trial court dismissed his complaint, preventing the lawsuit from going forward. The 10th Circuit reversed the trial court’s decision and reinstated the complaint based on one phrase in the ADA: the essential functions of a job.


“Dereck” has a disability, either a bad back or a torn rotator cuff or both. He began working for Bama Companies, Inc., through a temporary employment agency in January 2015. He was first assigned to perform general production work at a Bama plant on 66th Street in Tulsa. However, when that work aggravated his back issues, he was transferred to the 11th Street plant, where he worked for 2 months with a reasonable accommodation being provided “on occasion.” The temp agency paid Dereck’s wages, but Bama determined his work assignments, pay rate, work hours, and job duties.

In June 2015, Bama offered Dereck a permanent job at the 11th Street plant at a slightly higher hourly wage if he could pass its physical demand assessment (PDA). Dereck underwent the PDA. He later alleged in his complaint that he was able to perform all the required tasks during the assessment. However, Bama informed him that he hadn’t passed the PDA, and his employment offer was being withdrawn. Soon after, he filed a charge of discrimination based on his disability.

Essential Job Functions

The ADA prohibits employers from discriminating against employees with disabilities who are “qualified individuals.” A qualified individual is someone who, with or without reasonable accommodations, is able to perform the essential functions of a job. Under the ADA, an employer is required to make reasonable accommodations for a qualified individual unless the accommodations would impose an undue hardship on the employer.

A job function is considered essential if it is the reason for the job’s existence, there are a limited number of people who are available to perform the job function, or the person holding the job was hired because of his ability to perform a highly specialized function. An employer can demonstrate that a job function is essential by pointing to a job description, the consequences of not requiring the employee to perform the function, or the amount of time spent by the employee performing the function.

The employer will ordinarily determine the essential functions of a job. Although a reviewing court will give the employer’s determination great weight, the employer’s opinion about which functions of a job are essential isn’t the final answer. A court will consider multiple factors to determine if the duty at issue is truly an essential job function.

PDA Isn’t Determinative

Bama argued that an employee’s failure to pass the PDA was proof that he couldn’t perform the essential functions of a general production worker job. The appellate court found that argument troubling.

Dereck had been working for Bama as a general production worker for 5 months before he was offered a permanent job. The court realized that it didn’t have before it evidence of the actual tasks he had been asked to perform during the PDA or any information about why he hadn’t passed the PDA. However, it rejected the theory that failing to pass the PDA was conclusive proof of whether an employee could perform the essential functions of the production job.

Even more persuasive, at least at this beginning point in the lawsuit, was the fact that Dereck had been able to perform the essential functions of the job in the past. Past performance is indicative of an ability to perform a job in the present. The court also referred to a number of cases from other regions in which courts have allowed an employee to go forward with an ADA claim based on similar facts.

Complaint Stands If It Allows Court to Infer ADA Violations

An ADA complaint consists of allegations made by an employee that he believes support a violation of the Act. Statements in a complaint are not facts. The employee must later present evidence to prove that each allegation is true.

The appellate court realized that its decision was based solely on the allegations made in the complaint. Its decision in favor of Dereck doesn’t necessarily mean that he will ultimately be successful in his lawsuit. But it does mean that he has the green light to try to find evidence that may ultimately prove his claim of discrimination. Iselin v. the Bama Companies, Inc., Fed. Appx., 10th Circuit, No. 16-513, May 26, 2017.


The essential functions of a job are crucial in an ADA claim. You should define the essential job functions well before you begin the hiring process. Before starting to search for a new employee, draft a detailed written job description. Analyze how the job was performed by the previous employee, and use that information to determine the essential job functions.

If you’re going to use a physical test, like Bama did in this case, you should explicitly state how the components of the test relate to the essential functions of the job. Otherwise, a court may be asked to determine the essential job functions in the midst of litigation.

Barbara J. Koenig, a contributor to New Mexico Employment Law Letter, can be reached at