Job description includes the requirement of the job. It includes the job title, job location, job summary, job duties, equipments to be used, relation to other jobs, nature of supervision and working conditions etc.
On the other hand the Job specification is the measuring rod of the personnel. It consists the qualities required for the performance of the job like educational qualification, experience, mental abilities, physical measurement etc. the proper assessment of these qualities depends upon the judgment of number of people like job analyst, job holder, supervisor.
This is the difference between job description and job specification