A good job description covers the role's purpose, main responsibilities, required and preferred qualifications, the skills needed, the reporting line and practical details such as location and hours. It is often written or updated at the requisition stage with the hiring manager. A warehouse supervisor JD, for example, might list shift leadership, health and safety knowledge and experience with stock systems, each of which can become a screening criterion.
Because screening questions, interview guides and scoring rubrics are usually built from the JD, any vagueness or inflated requirement carries through the whole process. Separating must-haves from nice-to-haves, describing outcomes rather than years of experience where possible, and reviewing the JD with the hiring manager before launch all make later screening more accurate and easier to defend.