What it means
Topical relevance is how completely your site covers the related entities and questions that make up a topic. It is the term Google's own signals use for what SEOs long called topical authority. Kevin points to internal doc leaks and public signals from Google showing topical relevance is a real ranking factor: The more fully you cover a topic's entities and questions, the stronger your position. He treats topical relevance and topical authority as the same idea, with topical relevance being the name grounded in Google's documentation.
Why it matters
The doc leaks moved topical authority from a buzzword you cannot defend to a ranking factor you can point to. Kevin spent years skeptical, calling topical authority an SEO “ghost concept” people used to justify link-building or content-depth plays, until the leaks showed topical relevance is real and measurable. That matters when you ask for content budget, and it matters more now: In the era of AI Overviews (AIOs) and LLM-powered snippets, how completely you cover a topic decides whether you earn the click or get buried.
Say a mid-market B2B SaaS company has 30 pages on its core topic but leaves half the related subtopics uncovered. A competitor covering 90% of the topic's entities outranks it across the board. When the first company closes those gaps, its rankings on 40 queries it never directly targeted climb from page 3 to page 1, because Google reads the fuller coverage as stronger relevance.
How to use this knowledge
Stop pitching topical authority as a vague idea. Frame it as topical relevance, the coverage of entities and questions Google's signals reward, and measure your coverage against the topic. Map the entities, subtopics, and questions that define your topic, then close the gaps with content and internal links. Pair topical relevance with brand authority, which Kevin calls a close cousin, since both shape whether you earn clicks in AIOs and snippets.
Growth Memo guidance
Internal docs leaks and public signals from Google show that topical relevance, ie, how completely a site covers related entities and questions, is a real and important factor in ranking. — How to measure topical authority
The idea behind Topical Authority is by covering all aspects of a topic, sites get a ranking boost. — Topical Authority: myth or reality?
Topical authority — the older SEO name for the same idea, now grounded in Google's term topical relevance.
Brand authority — what Kevin calls a close cousin, shaping clicks in AIOs and snippets.
Entity coverage — how completely you address the entities that define a topic, which topical relevance measures.
Query share — a way to quantify how much of a topic's demand your coverage captures.
Content clusters — the structure for covering a topic's entities and questions.