Topical authority used to be a ranking concept. Now it decides whether ChatGPT names your brand in an answer or ignores it entirely. If you want AI engines to recommend you across a subject area, not just win one lucky prompt, you have to be seen as the reference point for that topic. That means depth, coverage, and consistency across every related question a user might ask.
A recent Semrush study, done with Kevin Indig and Growth Memo, looked at exactly how this plays out inside ChatGPT. Their dataset covered 1,094 US categories tracked monthly from January through June 2026, including 283,215 domain-category citation observations and 76,493 brand-mention observations. The finding that matters most for anyone building a content program: topical authority tends to spread into adjacent categories, but only when you have genuine depth in a related one first.
This guide covers what topical authority means in the AI era, how citations and brand mentions behave differently, and a practical method for building and measuring it so your visibility sticks.
What topical authority actually means now
Topical authority is the degree to which a domain is treated as a credible, comprehensive source on a subject. In traditional search it influenced rankings across a cluster of related queries. In AI search it does something more visible: it determines whether an engine cites you as evidence and whether it names your brand in the response text.
Those two outcomes are not the same, and the Semrush study makes the distinction concrete. Citations are the sources ChatGPT links to as evidence. Brand mentions are the brand names ChatGPT writes directly into the answer. You want both, but they respond to different signals, and understanding that gap changes how you plan content.
The bar for a mention is higher than the bar for a citation
According to the Semrush analysis, in categories close to a brand's core expertise, brands were cited as a source in 74% of appearances, mentioned by name in 44%, and both cited and mentioned in 34%. In categories distant from that core expertise, those numbers dropped to 50% cited, 25% mentioned, and just 9% both cited and mentioned.
Being cited held up reasonably well across the distance. Being named alongside a citation was strongly tied to relatedness: cited-and-named appearances were nearly four times higher in close categories than in distant ones. Of the citations in the least related categories, only 18% also included a named brand, versus 46% in the most relevant ones.
Topical authority tended to give brands a stronger starting point when expanding into adjacent categories, not a free pass into unrelated ones.
Semrush, ChatGPT topical focus study
The practical reading: a strong, well-sourced page can get cited almost anywhere if it meets ChatGPT's criteria of relevance, authority, and freshness. But getting your brand named, the outcome that actually drives recognition and demand, happens mostly in and around your area of proven expertise.
Depth beats breadth for topical relevance in SEO
One of the clearest signals in the study is that depth in a category mattered more than breadth for brand mentions. Brands that consistently appeared across a category's prompts were the ones associated with successful expansion into new categories. Showing up once in 20 categories did not build a higher brand-mention share.
This is the argument against the scatter-gun content approach. Publishing a single article on twenty loosely related topics spreads you thin and rarely produces authority anywhere. Covering one subject thoroughly, then expanding into the category next door, compounds. In the study's terms, a brand's core expertise was defined as any category where it had already appeared in at least three of five prompts, and closeness to that core predicted how far the authority traveled.
Industry changes the rules
Topical authority in AI search does not behave identically across sectors. In the brands Semrush analyzed, finance and real estate saw broader coverage associated with more citations. Legal and healthcare set a higher bar: even full prompt coverage and repeat citations did not reliably translate into brand-mention share.
If you operate in a high-trust vertical, expect the engine to be more conservative about naming you. That is a signal to invest harder in demonstrable expertise, author credentials, original data, and third-party validation rather than expecting content volume alone to earn recognition.
How to build topical authority that carries into AI search
Building topical authority is a structured content exercise, not a one-off campaign. The workflow below reflects how depth, coverage, and adjacency compound over time.
- 1Pick one core category you can genuinely own, not five you can only touch. Map the full set of questions users and AI engines ask around it before you write a word.
- 2Build topic clusters: a strong pillar page supported by focused articles that answer every meaningful sub-question. Interlink them so the relationship between subjects is explicit.
- 3Aim for prompt-level coverage. Instead of one broad article, make sure you have a credible answer to each distinct question in the category, since consistent appearance across prompts is what correlated with brand mentions.
- 4Strengthen source quality: original data, clear authorship, current information, and clean structure. These are the relevance, authority, and freshness signals that earn citations.
- 5Earn external validation through digital PR and links so your authority is recognized off-site as well as on it.
- 6Only expand into an adjacent category once you are consistently cited and mentioned in the current one. Choose the next category by genuine closeness, not by keyword volume alone.
A disciplined content strategy built on real keyword research is what turns this from a list into a repeatable system. The goal is not more pages. It is more complete coverage of the subjects you can credibly claim.
Optimizing for citations and brand mentions
Because citations and mentions respond to different signals, treat them as two objectives. Citations reward pages that are structured to be quoted: clear headings, direct answers, defensible facts, and freshness. That is the heart of answer engine optimization, where the aim is to be the source an engine pulls from.
Brand mentions are earned by concentration. The more consistently you appear as the authority across a topic, the more likely the engine is to name you rather than just link you. That requires the depth-over-breadth approach plus the wider AI search optimization work that ties your brand to a category in the model's understanding. Solid technical SEO sits underneath all of it, because content that cannot be crawled and parsed cannot be cited.
How to measure topical authority
Measure the two signals separately, matching how the engines behave. Track citation share (how often you are the linked source in a category) and brand-mention share (how often you are named in the answer text) across the full set of prompts for each category you target.
- Category prompt coverage: what share of a category's questions return your content at all.
- Citation share: your presence as a linked source relative to competitors in the same category.
- Brand-mention share: how often ChatGPT and other engines name you directly.
- Adjacency signals: whether authority in a core category is starting to appear in a genuinely related one.
- Trend over time: consistency across prompts and months, since a single appearance is not authority.
Feed these into a reporting cadence you can act on. Clear SEO reporting that separates citations from mentions tells you whether to deepen an existing category or start expanding into the next one.
Frequently asked questions
Does topical authority transfer between related categories in ChatGPT?
Partly. The Semrush study found that citations spread fairly readily across categories, while brand mentions concentrated near a brand's core expertise. Authority gives you a stronger starting point in adjacent categories, but it is not a free pass into unrelated ones. Expansion worked best when the next category was genuinely close to one the brand already answered well.
How long does it take to build topical authority?
There is no fixed timeline. Authority is built through consistent, comprehensive coverage of a category over time, not a single publishing sprint. The study associated brand mentions with brands that appeared repeatedly across a category's prompts, which means sustained depth rather than a quick burst of content.
What is the difference between a citation and a brand mention?
A citation is a source ChatGPT links to as evidence in its answer. A brand mention is your brand name written directly into the response text, which may be neutral, positive, or negative. Citations are easier to earn with strong, well-sourced pages. Mentions require deeper, more concentrated authority in the topic.
Is topical authority only about content?
No. The study notes that topical authority is one factor among several. Writing style, content quality, originality, overall brand authority, and third-party mentions all play a role too. Content depth is central, but it works alongside links, technical health, and off-site recognition.
Turn topical depth into AI visibility
Winning in AI search is a topic-level game, and the brands that get named are the ones that own a subject rather than dabble across many. If you want a content program built to earn citations and brand mentions across the categories that matter to you, talk to LASEO and we will map the clusters, coverage, and measurement plan to get you there.