Where the job description focuses on the activities involved in carrying out a job, a job specification looks at the qualities of a person performing the job. It is the list of the competencies, that is, knowledge, skills, abilities and characteristics associated with effective job performance. Knowledge refers to factual or procedural information necessary for successfully performing a task.
A skill is an individual's level of proficiency at performing a particular task – the capability to perform it well. With knowledge and experience, you could acquire skill in the task of preparing job specifications.
Ability, in contrast to skill, refers to a more general enduring capability that an individual possess. A person might have the ability to cooperate with others or to write clearly and precisely. Finally, other characteristics might be personality traits such as someone's persistence or motivation to achieve. Some jobs also have legal requirements, such as licensing or certification.
In developing job specification, it is important to consider all of the elements of the companies. In contrast to task, duties and responsibilities, competencies and characteristics of people are observable only when individuals are carrying out TDR's of the job and afterwards, if they can show the product of their labor. Thus, if someone applied for a job as a news photographer, you could not simply look at the individual to determine whether he or she can spot and take effective photographs. However, you would be able to draw conclusions later about the person's skill by looking at examples of his or her photograph.
Operations that run 24 hours a day have special job requirements. For most people working at night disrupts their normal functioning and may cause disorders such as fatigue, depression, and obesity. However, people show wide variability in how well they respond to working at night. Research has found that people who work well at night tend to sleep easily at different times of day, like to take naps, and exercise regularly.