GEO · The Mechanics

How Do AI Search Engines Decide What to Recommend?

Every AI answer blends two sources: what the model learned, and what it retrieves right now. Here are the signals that recur across every system, and the honest limits of what anyone knows.

Updated: July 2026
Written by: Andrew Odgers, Managing Director
Reading time: 7 minutes
The short answer

AI recommendations blend two sources: the model's training knowledge (what the web has said about you over time) and live retrieval (what it finds and often cites at answer time). Across every system, five signals recur: clarity (one name, one story, machine-readable facts), presence in the retrieved sources, corroboration by independent sources, reputation via genuine reviews, and content that answers directly. The honesty: no published algorithm exists, answers vary run to run, and AI visibility is a distribution, not a position. What a business controls is the record the machine reads, entirely.

The two sources

Training knowledge, live retrieval, and the five signals every system rewards

Every AI recommendation is a blend of two sources, and understanding both explains most of GEO. The first is training knowledge: what the web said about businesses, places and reputations up to the point the model was trained, baked into its weights, which is why long-standing consistent presence pays and why a business the internet has described three different ways gets described confusedly back. The second is live retrieval: most modern systems also search the web at answer time, read what they find, and compose the response from those retrieved sources, often with visible citations. A recommendation is the model's synthesis of both, which is why the work in the what-is guide runs both layers: the slow-built record and the pages retrieved today. Across every major system, five signals recur, and observed-everywhere is the strongest claim honest practice can make. Clarity: businesses described plainly and consistently, one name, one story, machine-readable facts via structured data, get represented accurately, and muddle gets echoed as muddle. Presence in retrieved sources: appearing in the pages, directories, review platforms and articles the systems actually pull at answer time. Corroboration: multiple independent sources agreeing about who you are and what you do, because a claim made once is an assertion and a claim made everywhere is a fact, as far as a model can tell. Reputation: reviews and ratings, which systems both read as evidence and echo into their answers. And genuinely useful content: pages that answer the question directly, with visible expertise, are what gets quoted into the response, the depth-and-authority machinery treated fully in the visibility factors pillar.

SIG 01

One clear story

Consistent name, plain description, machine-readable facts: muddle in, muddle out.

SIG 02

Corroborated everywhere

Independent sources agreeing: to a model, a claim made everywhere is a fact.

SIG 03

Worth quoting

Direct answers, visible expertise, genuine reviews: the material engines lift into responses.

The honesty and the control

What nobody knows, why answers vary, and what a business entirely controls

The honesty section, because this field attracts sellers of certainty: there is no published algorithm to know. No AI company discloses its recommendation logic, the systems are updated frequently and without notice, answers vary between sessions and phrasings, and the models themselves cannot reliably explain their own choices. What responsible practitioners work from is observation at scale, asking the systems many questions, noting who gets named and what those businesses have in common, and testing changes against outcomes, which produces the recurring signals above and no more. Anyone selling certainty about the machine's rules is selling something the machine's makers do not have. The variance deserves its own explanation, because it changes how visibility should be judged. Generation is probabilistic and retrieval is live: the models compose answers rather than looking them up, so wording, ordering and sometimes the shortlist itself vary between runs; the retrieved sources change as the web changes; the systems update underneath. For a business this means AI visibility is a distribution, not a position: the useful questions are how often you are named, how accurately you are described, and whether the trend improves, which is exactly the framing of the measurement guide. And the systems differ in machinery more than in what they reward. They differ in whose index they retrieve from, how much they cite, and the balance of training knowledge against live sources, which is why the ChatGPT, Gemini and Perplexity guides each cover their engine's specifics; but the five signals hold across all of them, because every system faces the same problem, deciding from the public record who can be trusted. Which lands on the sentence that is the entire honest promise of GEO: no business controls the model's output, and every business controls the record the model reads. How clearly it is described everywhere; whether its pages answer directly enough to quote; whether its facts are machine-readable; whether independent sources corroborate it; whether its reviews are genuine and healthy. Build for the record, and every engine, present and future, reads it.

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Frequently asked

How AI engines decide

Where do AI recommendations actually come from?
Two sources, blended. The model's training knowledge: what the web said about businesses, places and reputations up to the point the model was trained, which is why long-standing consistent presence pays. And live retrieval: most modern systems also search the web at answer time, read what they find, and compose the response from those retrieved sources, often with citations. A recommendation is the model's synthesis of both, which is why GEO works both layers: the slow-built record and the pages retrieved today.
What signals recur across the different AI systems?
Five patterns show up everywhere. Clarity: businesses described plainly and consistently, one name, one story, machine-readable facts, get represented accurately. Presence in retrieved sources: appearing in the pages, directories, review platforms and articles the systems actually pull. Corroboration: multiple independent sources agreeing about who you are and what you do. Reputation: reviews and ratings, which systems both read and echo. And genuinely useful content: pages that answer the question directly, with visible expertise, are what gets quoted. Observed patterns, not published rules, but observed everywhere.
How honest is anyone being about the algorithm?
The honest position is that there is no published algorithm to know. No AI company discloses its recommendation logic, the systems are updated frequently, answers vary between sessions and phrasings, and the models themselves cannot reliably explain their own choices. What responsible practitioners work from is observation at scale: asking the systems thousands of questions, noting who gets named and what those businesses have in common, and testing changes. Anyone selling certainty about the machine's rules is selling something the machine's makers do not have.
Why does the same question get different answers on different days?
Because generation is probabilistic and retrieval is live. The models compose answers rather than looking them up, so wording, ordering and sometimes the shortlist itself vary between runs; the retrieved sources change as the web changes; and the systems themselves are updated without notice. For a business this means AI visibility is a distribution, not a position: the useful questions are how often you are named, how accurately you are described, and whether the trend is improving, which is exactly how GEO performance should be measured.
What does a business actually control in all this?
The inputs, entirely. How clearly and consistently the business is described everywhere it appears. Whether its pages answer real questions directly enough to be quoted. Whether its facts are machine-readable through structured data. Whether independent sources, directories, review platforms, press, communities, mention and corroborate it. And whether its review record is genuine and healthy. No business controls the model's output, and every business controls the record the model reads, which is the entire honest promise of GEO in one sentence.
Do the major systems differ in how they choose?
In machinery yes, in what they reward less than you would think. They differ in whose search index they retrieve from, how much they cite, and how much they lean on training knowledge versus live sources, which is why the ChatGPT, Gemini and Perplexity guides in this series each cover their engine's specifics. But the recurring signals, clarity, presence, corroboration, reputation, useful content, hold across all of them, because every system faces the same problem: deciding, from the public record, who can be trusted. Build for the record and every engine reads it.