From my experience, it is very difficult to toe the line between being too specific and too vague when writing a job description. On one hand, if the description is too broad, you will have an endless pile of applications from unqualified candidates to sift through. This could cause you to miss the applications from the qualified applicants, and hire someone subpar for the job. Conversely, if the job description is too specific or complicated, you may have very few applicants because most people don’t apply to jobs if they don’t meet all of the listed qualifications. This limits your pool of applicants and may prematurely eliminate the best candidate for the job.
Developing a job description can also be difficult because it is nearly impossible to cover all the necessary skills for the job in a small posting. Unexpected situations arise all the time which may require a skillset that you never knew your employee would need. For example, the Task-KSAO analysis approach can be very helpful in outlining the specific duties of the job and the qualities needed to do them, but it can’t predict the unpredictable, so there will always be a piece missing.
Maintaining job descriptions for current employees is important because it allows the company to monitor and measure an employee’s performance against expectations, which can be helpful in determining promotions and necessary disciplinary actions. However, it can be a difficult task because only the employee truly knows what they do on a day-to-day basis. There could be a large discrepancy between what the employee does each day and what their job description says they should be doing, which could negatively skew performance reports.
Despite the challenges of creating and managing job descriptions, it is almost always best practice to have them in place. They can serve as guides for hiring and firing decisions and benchmarks for employees who are acclimating to a new role. They can also help the company track what departments, and what employees within those, are doing what kinds of work.