Essential Functions Guide

What are essential functions and how are they identified?

Essential functions are the fundamental, crucial job duties performed in a position. They do not include marginal functions, which are extra or incidental duties. A function may be essential because:

  • The position exists to perform that function.
  • There are a limited number of employees available who could perform that function.
  • The function is highly specialized, and the incumbent is hired for special expertise or ability to perform it.

Essential functions must be identified for each position, not job class, and they must be based on the work performed, rather than the capabilities of an individual. A job analysis can help identify essential functions by determining which functions an employee actually performs.

It is also critical to separate the function, which creates a desired outcome, from the method, which is a way of performing a function. An essential function is a completed task, not how that task is completed. Results­ oriented language will help ensure this distinction. For example, it may be an essential function of a job to “relocate (as opposed to lift) 50 lb. boxes.”

Why identify essential functions?

  • To avoid inconsistent or unfair employment decisions.
  • To define positions and ensure that employees understand what is expected of them.

The Washington State Law Against Discrimination (WLAD) and the federal Americans with Disabilities Act (ADA) protects qualified individuals with disabilities. These individuals, who may be applicants or employees, meet the valid skill, experience, education, or other requirements of a position and can perform its essential functions with or without reasonable accommodation. The ADA also protects non-disabled employees from being perceived by their employers as disabled.

When should essential functions be identified?

  • When a position is established, vacant, or reallocated.
  • Prior to interviewing candidates for a position.
  • Prior to conducting any conditional offer medical examinations.

The best time to identify essential functions is when a position is established. An employer can refer to those functions if it engages in the reasonable accommodation process.

If any of the criteria below are met, the function is likely essential. In addition, the terms of the collective bargaining agreement may be relevant to determining a position's essential functions. It is critical that the essential functions are accurate for the particular position. 

Is the function a primary reason for which the position was established?

For example: A floating supervisor job exists to provide a substitute when regular supervisors on the day, night, and graveyard shifts are absent. So, an essential function of the job may be to work at any time of day.

Would removing the function fundamentally change the position, or eliminate the need for the position?

For example: Removing the function “provide guidance and resources to clients” from a customer service position would fundamentally alter the job and question the need for it.

Is transferring the function impossible due to a lack of available employees?

For example: It may be an essential function for a file clerk to answer the telephone if there are only three employees in a very busy office and each employee has to perform many different tasks.

Are there severe consequences if the position is not required to perform the function?

For example: A firefighter may rarely have to carry a heavy person from a burning building, but it is an essential function of the job because of the serious consequences of not performing it.

Does the function require specialized expertise?

For example: Dual language positions may have essential functions related to speaking a second language fluently. Or, accountant positions may have essential functions that require licensure as a Certified Public Accountant.

Does the percentage of time spent on a function determine whether or not it is essential?

No, a function may be essential regardless of the amount of time spent performing it. For example, a pilot is required to take off, fly, and land airplanes. The majority of the pilot’s time is spent flying in the air; however, it is an essential function of the job to land the plane.

Can an employer change the essential functions of a job?

Yes, an employer may change the essential functions of a job for business reasons. If the position is filled, the employer should notify the incumbent that the essential functions will be changing and, if possible, involve him or her in the process.

Who is responsible to demonstrate that a function is essential?

If challenged, management must demonstrate that a function is essential.


Notes: This information has been provided by the Office of Financial Management, State Human Resources office. 

Employers with questions should contact their assigned Assistant Attorney General in the Labor and Personnel Division.