Explanation:

A job specification defines the knowledge, skills and abilities that are required to perform a job in an organization. Job specification covers aspects like education, work-experience, managerial experience etc. which can help accomplish the goals related to the job. Job specification helps in the recruitment & selection process, evaluating the performance of employees and in their appraisal & promotion. Job specification, along with job description, is actually derived from job analysis. Collectively, job specification and job description help in giving a overview of the job in terms of its title, position, roles, responsibilities, education, experience, workplace etc.
The importance and purpose of job specification is a thoroughly understand the specific details of a job. Jobs can be of different types and can require a different skill sets to get the maximum output from a particular. Job specification gives important details related to the job like education & skills, prior work experience, managerial experience, personality traits etc. which would help an employee accomplish the objectives of a job.