Topical Authority: What It Is and How to Build It
Topical authority is the degree to which search engines treat a site as a dependable source on a whole subject, not just on one keyword. It is why a focused specialist site can outrank a much larger generalist on its home turf, and why new pages on a well-covered topic tend to rank faster than pages on a site that dabbles.
This guide is for owners and marketers deciding what to publish next. It covers what the term means, what Google has actually confirmed, what the 2024 leak shows Google stores, how to measure your own site’s focus with a simple embedding test, and how to build authority on purpose rather than by accident.
On this page
- What topical authority means
- Is topical authority a ranking factor?
- What the leak shows: siteFocusScore and siteRadius
- Topical authority vs Domain Authority
- How do you measure topical focus on your own site?
- How to build topical authority deliberately
- Where topical authority fits in AI search
- Getting your site’s topical authority right
What topical authority means
Topical authority is subject-level trust: a site that covers one area thoroughly, accurately and consistently earns the benefit of the doubt on related queries. It has three ingredients.
- Focus. Most of the site is about one subject or a few closely related ones.
- Depth. The site answers the main questions and the awkward follow-ups, not just the head terms.
- Recognition. Other sites, and people, refer to it on that subject.
None of these is a single page’s property. That is the point. Topical authority is a site-level idea, and it explains results that page-level SEO cannot, like a thin-looking page from a specialist outranking a polished page from a generalist.
Is topical authority a ranking factor?
Google has not published a general “topical authority” score, but it has confirmed the idea in one area and the leak shows related data in another. Both are worth separating from the marketing around the term.
What Google has said. In May 2023, Google described a topic authority system for news that helps it identify which publications have expertise on particular subjects or locations. The signals it named were notability for a location or topic, influence and original reporting, and reputation. That system is about news. It is not evidence of an identical system for every site.
What Google’s guidance implies. The helpful content guidance asks creators whether they “decide[d] to enter some niche topic area without any real expertise, but instead mainly because you thought you’d get search traffic.” That is Google telling you, in plain terms, that sprawling into unrelated subjects for traffic is a warning sign.
What remains unknown. Nobody outside Google knows how site-level topic signals are weighted, or whether they apply the same way to every query. Anyone who quotes you a number is guessing.
What the leak shows: siteFocusScore and siteRadius
The 2024 leak of Google’s internal Content Warehouse API documentation includes a module that stores exactly the kind of topic-focus data this concept assumes. Google stores these attributes; the leak does not show how much they are weighted.
The module is QualityAuthorityTopicEmbeddingsVersionedItem. Its fields, with the leaked descriptions:
| Attribute | Leaked description | Plain reading |
|---|---|---|
QualityAuthorityTopicEmbeddingsVersionedItem.siteFocusScore | “Number denoting how much a site is focused on one topic.” | A focus score for the whole site |
QualityAuthorityTopicEmbeddingsVersionedItem.siteRadius | “The measure of how far page_embeddings deviate from the site_embedding.” | How spread out the pages are around the site’s center |
QualityAuthorityTopicEmbeddingsVersionedItem.pageEmbedding | “Compressed site/page embeddings.” | Vector representations of pages and the site |
CompressedQualitySignals.topicEmbeddingsVersionedData | “Versioned TopicEmbeddings data to be populated later into superroot / used directly in scorers.” | Where the topic data is carried per document |
Mike King’s analysis at iPullRank covers these fields and carries the right caveat: “We do not know how features are weighted in the various downstream scoring functions.” Rand Fishkin’s SparkToro write-up says the same about the whole leak: it does not show the weight of elements or prove which are used in ranking.
So what is safe to conclude? That Google represents pages and sites as embeddings, computes a site-level focus number and a spread number from them, and keeps them available to scoring systems. We cover the wider leak in the Google leak explained. The diagram below shows what “radius” means geometrically.
Scroll the diagram sideways to see all of it.
Topical authority vs Domain Authority
Domain Authority is a third-party link metric; topical authority is about subject focus and depth. They measure different things and should not be used interchangeably.
Moz defines Domain Authority as a score from 1 to 100 that estimates a site’s ability to rank, and says plainly that it “isn’t a direct ranking factor used by Google.” It is mostly a function of links. A site can have a high DA and no topical focus at all, like a big general news site, or a modest DA and deep authority on one narrow subject.
Both “Is domain authority real?” and “What does Domain Authority do?” showed up in the People Also Ask box for “topical authority” in our 22 September 2026 check, so the confusion is common. The short answer: DA is a real Moz metric and a reasonable proxy for link strength. It is not a Google score, and it says nothing about whether you cover a subject well.
How do you measure topical focus on your own site?
You can approximate your own site focus and radius with embeddings in an afternoon. It will not reproduce Google’s numbers, but it shows which pages sit far from your core, and that is the actionable part.
The method, step by step:
- Export your indexable URLs. Your XML sitemap or a crawl is fine.
- Extract a representative text for each page. Title, H1 and the first 300 words work well. Skip navigation and footers.
- Embed each text with any sentence embedding model. Open-source options like Sentence Transformers run locally; the major AI providers offer embedding APIs.
- Compute the site centroid, the average of all page vectors. This is your stand-in for a site embedding.
- Measure each page’s cosine distance to the centroid. The average distance is your stand-in for radius.
- Sort by distance and read the top 10 to 20%. Those are your outliers.
The flow below is the same method as a diagram.
Scroll the diagram sideways to see all of it.
A simpler, no-code version works too. Tag every URL in a spreadsheet with its topic, then calculate what share of indexable pages belongs to your core two or three topics. If less than half of your site is about what you sell, you have found the problem without any vectors.
Read the output with judgment. Your about page, contact page and legal pages will always sit far from the centroid. Ignore them. The pages worth acting on are blog posts and landing pages that were written for traffic rather than for your customers.
How to build topical authority deliberately
You build topical authority by choosing a subject you can genuinely cover, mapping its question space, publishing the whole map, and connecting it with links. Here is the order we work in.
1. Pick the subject you can defend. It should match what you sell and what you actually know. Google’s reviews system, for example, says it rewards content “written by experts or enthusiasts who know the topic well,” per its ranking systems guide.
2. Map the question space, not a keyword list. Include definitions, mechanisms, comparisons, costs and failure cases. People Also Ask is a good free source; our guide to People Also Ask covers the mining method.
3. Build it as a hub. One pillar that defines the subject, spokes that answer each question fully, and navigation that makes the structure obvious. We cover design choices in content hubs and pillar pages and the AI angle in topic clusters built for AI citation.
4. Link the cluster tightly. Every spoke links to the pillar and to its closest siblings with descriptive anchors. See our internal linking guide.
5. Cover entities, not just phrases. Name the tools, standards, organizations and people your subject involves. That is the practical core of semantic SEO.
6. Prune the drift. Use the measurement above. Improve, merge or retire pages that pull your centroid away from the subject.
7. Earn recognition. Original data, expert commentary and being cited by others on the subject turn coverage into authority.
| Signal | Helps focus | Helps depth | Helps recognition |
|---|---|---|---|
| Pruning off-topic posts | Yes | No | No |
| Answering follow-up questions | Yes | Yes | Sometimes |
| Pillar and spoke structure | Yes | Yes | No |
| Named expert authors | No | Yes | Yes |
| Original research or data | Yes | Yes | Yes |
| Links and mentions from the niche | No | No | Yes |
The layered model below shows why the order matters: recognition built on a sprawling, shallow site does not stick, because there is no coherent subject for it to attach to.
Scroll the diagram sideways to see all of it.
What does not work: publishing a hundred thin posts on loosely related keywords, or buying a batch of AI articles to “cover the topic.” That increases page count and, very likely, radius. It is also close to what Google’s spam policies call scaled content abuse.
Where topical authority fits in AI search
AI answer engines reward the same things, for a mechanical reason: they retrieve passages by meaning, and a site that covers a subject thoroughly has more passages close to more of the questions. We explain the retrieval side in semantic search.
There is a recognition effect as well. Sustained, consistent coverage of one subject makes it more likely that your brand is associated with that subject wherever models learn from the web. That is the connection between topical authority and entity SEO: the site becomes a known thing about a known topic.
Getting your site’s topical authority right
Start by measuring. Run the embedding test or the spreadsheet version, find the pages that sit far from your core, and decide what each of them is for. Then map the questions your core subject still leaves unanswered and publish those before anything new and unrelated.
Treat the leaked attributes as a reason to stay focused, not as a score to chase. Google stores siteFocusScore and siteRadius; nobody outside Google knows their weight. Focus and depth are worth having regardless, because they are also what makes a site useful to the people reading it.
If you want an outside view of how focused your site looks, and a plan for the cluster that would move it, that is part of our AI SEO service.
Frequently asked questions
What does topical authority mean?
Topical authority is the degree to which a site is treated as a dependable source on a whole subject rather than on a single keyword. In practice it shows up as a site ranking for many related queries in its niche, including new pages that rank quickly because the site has a track record on the topic.
Is topical authority a Google ranking factor?
Not as a single named score. Google has described a topic authority system for news, and the 2024 API leak shows Google stores site-level topic attributes such as siteFocusScore and siteRadius. The leak does not show how those attributes are weighted, so treat topical authority as a useful model, not a confirmed metric.
Is Domain Authority the same as topical authority?
No. Domain Authority is a Moz metric scored from 1 to 100 that estimates ranking strength, mostly from links, and Moz says it is not a direct Google ranking factor. Topical authority is about subject focus and depth, which a link-based score does not measure.
How long does it take to build topical authority?
There is no published timeline. On a new site, expect to publish and interlink a meaningful body of work on one subject before rankings broaden, usually months rather than weeks. An established site that tightens its focus can see changes sooner because it already has crawl history and links.
Can a site have topical authority on more than one topic?
Yes, but each topic has to be covered deeply on its own. Large publishers do this with separate sections and editors. A small site that spreads thinly across many unrelated subjects dilutes its focus, which is exactly what a measure like siteRadius would capture.
Does deleting off-topic content help topical authority?
Sometimes. Pages that are off-topic, thin and unvisited add little and pull the site's average away from its core. Improve, merge, or redirect them before deleting, and never remove pages that earn links or traffic without a redirect plan.