Why AI Engines Cite Different Sources for the Same Query

The short version: ask ChatGPT, Perplexity, Gemini and Google the same question, "best plumber in Toronto," and you get four different lists of sources pulled from four different corners of the web. ChatGPT reads a Google Maps panel and quotes review counts. Perplexity and Gemini read "best of" directories and the business's own site. Google, for most commercial local queries we have tested, shows no AI Overview at all, and where it does answer a decision question it reaches for Reddit. Across the Toronto field tests we have published and the local-service sites we monitor, that split is the most consistent thing we see. A GTA trade, clinic or firm is not fighting one AI-visibility battle. It is fighting four, and each has its own entry ticket.

Same question, four neighbourhoods

Every answer engine does the same two things in order. It retrieves, then it writes. The writing is what you see. The retrieval is what decides who gets named, and it is the part almost nobody looks at.

Each engine retrieves from a different neighbourhood of the web. One pulls a places panel. Another runs a live search and favours roundup pages. A third reads its own index and the forums it has licensed. The model then writes a confident paragraph from whatever it retrieved, which is why the same Scarborough HVAC company can be the top pick on one engine and absent on the next.

We wrote the engine-by-engine mechanics up in our comparison of the five AI search engines. This piece goes one level down: what the retrieval neighbourhood looks like for a local-service query in Toronto, and what you have to own in each one.

ChatGPT: the Maps panel and the review count

When we asked ChatGPT for the best accountant, mortgage broker, med spa, law firm or real estate agent in Toronto, the answer came back the same way every time. A Google Maps style panel with a star rating, a review count, an address and a phone number for each business, followed by a few sentences of commentary. The review numbers were the stated reason for the pick. In the accountants study, the top firm sat at a 5.0 across roughly 880 reviews, and ChatGPT said so.

Two public facts sit behind that panel. Suganthan Mohanadasan's network-traffic teardown showed ChatGPT often names brands from a training-data shortlist before it searches at all. And in August 2026 Yelp licensed its reviews and ratings to OpenAI, which is why a review-highlights field now appears in ChatGPT's local answers.

For a Toronto business the implication is blunt. Your Google Business Profile, your categories and your review depth are the input ChatGPT reads, and for trades the big rating directories like HomeStars are part of the same surface. A polished website with twelve reviews loses this room to a plain website with six hundred.

Perplexity and Gemini: the directory and your own site

Perplexity and Gemini answer in prose and cite pages. The pages they cite are, overwhelmingly, local roundups and the business's own site.

The roundups are the "best accountants in Toronto" and "top HVAC companies in the GTA" lists that most owners dismiss as vanity listings. Perplexity quoted them directly in every vertical we tested. Gemini cited the same kind of page and added a twist: it repeatedly surfaced the firm that published its licence number, its FSRA registration or its TSSA certification in plain text, and it leaned toward decision-support writing that helps the reader choose.

Perplexity has one structural advantage for a smaller business. Suganthan's Perplexity teardown found it never skips the live web search, so a newer firm is not locked out by a memorised shortlist the way it can be on ChatGPT.

One caveat we owe you. In the med spa test, Perplexity rendered a live places map and Gemini returned place cards with ratings and hours. Review-heavy consumer categories pull every engine toward Maps data. The directory-and-site pattern dominates professional services and trades. It is not a law of nature.

Google: often no AI answer, and Reddit when there is one

Google surprised us more than any other engine, in two directions.

First, for "best accountant," "best mortgage broker," "best HVAC company," "best med spa" and "best real estate agent" in Toronto, Google produced no AI Overview at all. It showed sponsored ads, a local Maps pack and organic listicles. The law-firm query was the exception, and there the Overview appeared below the ads and the map pack. If you have been told AI Overviews are stealing your local commercial clicks, check the query first.

Second, when Google does bring a community source into an answer, it is Reddit. Google's licensing deal with Reddit is public. In our tracking of the local-service sites we monitor, personal-decision questions ("should I get a mold inspection before I buy") went to Reddit and Facebook threads inside the AI Overview, and a dedicated answer page we had shipped for one of them still lost the slot to a thread. That story is in the queries Reddit wins that your website can't. Even where no Overview fires, r/askTO threads sat high in the organic results for HVAC and med spa queries, with homeowners trading names.

So Google's local-service neighbourhood is the Maps pack, the listicles and the subreddit. Classic local SEO still runs that room.

Claude reads Brave, not Google

Short section, because the fix is specific. Independent studies cited in the GSC Wizard Brave playbook, from Profound and MERJ, put most of Claude's citations inside Brave Search's top ten. Brave has its own technical rules: no JavaScript execution on the double-fetch, no redirect on the entry URL, canonical tag in the HTML head. A Toronto firm that redirects its bare domain to www can be healthy in Google and invisible to Claude. If your buyers are B2B or technical, that is a neighbourhood worth checking on its own.

What the split looks like in our tracking

We run the same prompts across the engines for the local-service sites we monitor and log, per engine, whether the site was named and whether it was cited. The spread is not subtle. For the same query set, citation rates have differed by more than 80 points between engines, and a site that owns a topic on one engine has been absent from another. That is four retrieval neighbourhoods disagreeing about who exists.

An AEO audit of a Toronto local-service business therefore has to run per surface. The items we flag most often map onto the neighbourhoods above:

• Thin Google Business Profile review depth, which removes the business from ChatGPT's panel and Google's map pack at the same time.
• Absence from the roundups and rating directories the engines quote, so Perplexity and Gemini have no page on which to find the firm.
• A specialty stated nowhere in plain text. Engines surfaced the CRA-audit specialist and the cross-border tax specialist because those firms said so, in words, near the top of the page.
• No genuine presence in the threads Google already trusts for decision questions.
• A redirect on the entry URL or client-rendered content, which quietly drops the site out of Brave and therefore out of Claude.

A two-minute scan with the free AEO checker catches the technical items on that list. The rest take real work.

What we would fix first for a GTA local-service business

Order matters, because each step feeds the next.

1. Build review depth on Google and keep it current. It is the one asset that pays on ChatGPT, on Google's map pack and in the Maps data Gemini increasingly reads. Reply to the negatives, since the reply becomes part of the text the model reads.
2. Get listed, accurately, on the roundups and directories your category's engines cite. For trades that is HomeStars and the contractor-rating sites. For professionals it is the legal, accounting or broker rankings. Study which pages Perplexity cites for your query and go get on them.
3. Write one answer-first page per intent and name the specialty in the first paragraph. "Best accountant," "small-business accountant" and "tax accountant" returned almost entirely different firms. Each intent is a separate contest.
4. Participate honestly where Google quotes the community. Real answers from a real, disclosed account in r/askTO and the trade subreddits. No link drops, no fresh promotional accounts.
5. Fix the Brave basics if your buyers use Claude: server-rendered content, canonical in the head, no entry-URL redirect.

Then measure each engine separately. A blended "AI visibility" score averages over four rooms that do not behave alike, and it will tell you that you are doing fine while one of them has never heard of you. If you would rather we run the measurement and the fixes, that is what our SEO and AEO service does for Toronto and GTA businesses.

FAQ

Why does ChatGPT recommend a different Toronto business than Perplexity for the same query? Because they retrieve from different places before they write. ChatGPT grounds local answers in a Google Maps style panel and quotes star ratings and review counts as its reasoning. Perplexity runs a live web search and cites local "best of" roundups and the business's own site. A firm with deep reviews but no directory presence wins on ChatGPT and vanishes on Perplexity.

Does Google show an AI Overview for "best plumber in Toronto" type queries? In our Toronto tests across accountants, mortgage brokers, HVAC companies, med spas and real estate agents, Google showed no AI Overview for the "best X in Toronto" query. It returned ads, a local Maps pack and listicles, often with Reddit threads in the organic results. Law firms were the exception. Check your own query before assuming the AI layer is there.

What does Google's AI Overview cite when it answers a local decision question? Community sources, especially Reddit, alongside canonical pages. For personal-decision questions in our tracking, the Overview co-cited Reddit and Facebook threads, and a purpose-built answer page on a site we monitor still lost the citation to a thread. The useful response is genuine, disclosed participation in those threads, not another page.

Do I need a different AEO strategy for each AI engine? The foundations are shared: a strong Google Business Profile, accurate directory listings, intent-specific pages that state your specialty plainly, and a site AI crawlers can read. The emphasis changes by engine. ChatGPT rewards review depth, Perplexity and Gemini reward directory presence and clear on-site claims, Google rewards classic local SEO plus community presence, and Claude rewards your Brave ranking. Measure each on its own rather than trusting one blended score.

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