means demonstrable subject knowledge on a topic. Within the framework it complements Experience (first-hand experience), Authoritativeness (reputation) and Trustworthiness (reliability).

Expertise becomes visible mainly through author information. A good author box or author page shows:

  • role and function,
  • relevant experience and areas of specialisation,
  • certificates, qualifications or publications,
  • links to official profiles.

In machine-readable form, expertise can be expressed through Person or ProfilePage markup with fields such as knowsAbout and jobTitle.

Importantly, claimed expertise must be genuine and verifiable. Invented qualifications or "Admin" as the author weaken credibility. Especially for expert guides, studies and , users and search engines expect recognisable professional context.