Job Description vs Job Posting vs Job Specification: What's the Difference?

The three terms are often used as if they mean the same thing, but they are different documents for different readers. A job description defines a role, a job posting advertises it to candidates, and a job specification lists the qualifications a person needs to do it. Getting them mixed up leads to postings that read like internal paperwork, or internal documents that read like adverts.

The three documents at a glance

What is a job description?

A job description is the standing definition of a role. It says why the role exists, what the person does, who they report to, and the conditions of the job. It is the document you return to for performance reviews, pay decisions, and settling questions about whether a task is part of the job. Because it supports those decisions, it should be factual and free of marketing language.

What is a job posting?

A job posting, also called a job ad or a vacancy notice, is the public advertisement. It starts from the job description but is written for a different purpose, which is to persuade the right people to apply. It adds things the description leaves out: what makes the team a good place to work, the pay and benefits, the location and hours, the deadline and how to apply. It leaves out detail that matters only inside the company.

A posting is also where legal requirements on advertising fall, such as including a pay range in places that require it. Our guide to pay transparency in job descriptions covers the rules in the US and EU.

What is a job specification?

A job specification (or person specification) describes the person rather than the role: the qualifications, skills, knowledge and experience needed to do the work well, and sometimes personal attributes. It is often a section inside the job description, rather than a separate document, but in some organisations, especially larger or public-sector employers, it is separate and used to score applicants in a consistent way.

A good specification separates what is essential from what is desirable, so that a shortlisting decision can be explained and repeated.

One role, three versions

Here is how a short extract from each document might look for a customer support role.

• Job description: "The Customer Support Specialist answers customer questions by email and chat, escalates bugs to engineering, and reports each month on the most common issues. Reports to the Head of Support."
• Job posting: "Join a friendly team of eight that answers real questions from real customers. You will fix problems in a single reply wherever you can, and help us make the product better. Salary [range]. Hybrid, two days in the office. Apply by [date]."
• Job specification: "Essential: one year or more in a customer-facing role; clear written English. Desirable: experience with a help-desk tool."

Do you need all three?

Not always. A small team can write one document with a clear structure and reuse it, as long as the public version is edited for candidates and the pay information is added. A larger organisation, or one that has to document its hiring decisions, usually benefits from keeping the three apart.

• Small team, one hire: write one job description, then a short posting from it.
• Growing company: keep a job description for each role, and write a fresh posting for each vacancy.
• Structured or regulated hiring: keep all three, and score applicants against the specification.

Common mistakes

• Posting the internal description. It tends to be dry and full of internal terms, and it often leaves out pay.
• Treating the specification as a wish list. If the essentials list is long, fewer qualified people will apply.
• Letting the description go stale. If the role has changed, the document, and every posting made from it, is wrong.
• Using the posting to make promises the job cannot keep. Candidates compare it with reality in the first month.

Where to go next

If you are writing one now, start with a free job description template and our full guide to writing a job description. For finished examples, see job description examples for 10 common roles.

Frequently asked questions

Is a job description the same as a job posting?

No. The description defines the role for internal use. The posting is the public advertisement made from it.

Is a job specification part of a job description?

Often it is a section within it, listing qualifications and skills. Some organisations keep it as a separate document for shortlisting.

Which one should I publish?

Publish the job posting. Keep the full description and specification for internal use, and share the relevant parts with candidates who reach interview.