What is the diference between a job specification and a job description and why are both important?

Is this for homework?

Job description is the summary of the job that is used by HR for new employees, for EEOC, and for job listings. It describes the job in summary form in an easy to read format.

Job Specifications are the exact job actions which must be taken to complete the job. The detailed specifics of the job.
I call them job procedures but specifications works.
It is the detail usually step by step with instructions while the job description is a summary.

Now a Job analysis is when you take a job and write down everything about it to analyze the procedures to find out if they can be streamlined, if they have changed, and if they need to change. It is used for changing classifications, for new job creation and sometimes for promotions.

I have a form for both job analysis and for job description, but I cannot post them here as I do not think they are small enough files.

Shirley