Writing the job description is normally preceded by a job analysis (link to page above).. The job analysis is a study of the job or role that helps the employer identify and describe the essential functions of a position, as well as the competencies, knowledge, skills and abilities (CKSA) needed to fulfill the functions (see Brief Job Analysis).
Step 2: Identify Essential Rather than Marginal Functions
To identify the essential functions of the job, first identify the purpose of the job, and the importance of actual job functions in achieving this purpose. In evaluating the importance of job functions, consider, among other things, the frequency with which a function is performed, the amount of time spent on the function, and the consequences if the function is not performed. In defining the essential functions of a job, it is important to distinguish between methods and results. For example, is the essential function moving a fifty pound box from one part of the lab to another, or is it carrying the box? While essential functions need to be performed, they often do not need to be performed in one particular manner (unless doing otherwise would create an undue hardship).
Step 3: Cover the Key Areas
Job descriptions describe the job and not the individual who fills the job. They are written narratives of the major duties and responsibilities of a job position or job role. The job description also states the results expected of anyone in the job. There are many formats used in preparing job descriptions. Typically, the key areas to include are:
Based at (business unit, section - if applicable)
Position reports to (line manager title, location, and functional manager)
Job Purpose Summary (ideally one sentence)
Key Responsibilities and Accountabilities (or duties typically 8-15 numbered points)
Dimensions/Territory/Scope/Scale indicators (the areas to which responsibilities extend and the scale of responsibilities - staff, customers, territory, products, equipment, premises, etc)
Hours of Work
Date and other relevant internal references
Step 4: Write in a Simple Style
Job descriptions should be written in brief and clear sentences. The basic structure for sentences in a job description should be "implied subject/verb/object/explanatory phrase." It is best to use action verbs like "types" and "files."