Article
What is GEO (Generative Engine Optimization)?
The technical term behind AIO — and what the Princeton paper revealed about how AIs choose their sources
GEO (Generative Engine Optimization) is the set of practices that increases how frequently a website is cited in responses generated by AIs like ChatGPT, Perplexity, and Google AI Overview. The term emerged in 2023 from a Princeton and Google research paper ("GEO: Generative Engine Optimization", Aggarwal et al.) that, for the first time, systematically measured which writing strategies and authority signals increase citation rate in generative engines.
Where the term GEO came from
The Aggarwal et al. paper was published in 2023 and is considered the first systematic academic research on the topic. The study analyzed more than 10,000 queries in generative engines and tested different content approaches — including the use of statistical data, fluent language, citations — to measure which format generated more citations.
The central finding: content with concrete data, direct language, and clear authority signals is cited much more frequently than generic content, even when the generic content ranks well on Google. This showed that SEO and GEO measure different things and require complementary strategies.
GEO vs. AIO: what's the practical difference
In the Brazilian market, the term that gained traction is AIO (AI Optimization) — more explanatory for managers and directors unfamiliar with the technical field. GEO is the preferred term in technical contexts, in conversations with experienced SEOs, and when citing the original paper.
The conceptual distinction is relevant:
| GEO | AIO | |
|---|---|---|
| Origin | Academic paper (Princeton/Google, 2023) | Market term |
| Scope | Narrow — focus on citation rate in generative engines | Broad — includes technical foundation (SEO) + citability |
| What it measures | Citation frequency in AI responses | Overall AI visibility (traffic, citations, technical coverage) |
| Relationship | GEO is a dimension within AIO | AIO is the umbrella |
In practice, the actions are the same. Schema.org, llms.txt, heading structure, E-E-A-T, paragraph citability — these are the same actions regardless of which name is used.
What the GEO paper revealed that changes strategy
The researchers tested different optimizations in content and measured the impact on citation rate. The most effective strategies were:
Including statistics and concrete data: increased citation rate by up to 40% compared to versions of the same content without specific data.
Fluent and direct language: clearly and objectively written content outperformed technical content or generic list format.
Citations to recognized sources: referencing studies, reports, and institutions increased the generative engine's perception of trustworthiness.
Direct answer in the first paragraph: RAG (Retrieval-Augmented Generation) systems tend to extract the most "extractable" text block — the one that answers the question completely without depending on prior context.
Why GEO doesn't replace SEO — it adds to it
One of the most important points of the paper is that visibility in traditional search and visibility in generative responses are independent metrics. A site can be on the first page of Google and not be cited by ChatGPT — and the reverse also happens.
GEO and AEO: are they the same thing?
Not exactly. AEO (Answer Engine Optimization) is an older term, emerging around 2015–2018, associated with optimization for voice assistants like Alexa, Siri, and Google Assistant. The tactics are similar (FAQ, direct answer, structured content), but the context is different: AEO thought about spoken responses; GEO/AIO thinks about text citations in generative models. For practical purposes, implementing GEO today covers what AEO proposed — with much more depth.
Implementing GEO doesn't require starting from scratch. For companies with established digital presence, the starting point is an audit that identifies the technical blockers and content gaps that prevent AIs from citing the site. FRT Digital performs this diagnosis with the AIO Score — a structured evaluation that maps the starting point and defines actions with the highest impact on generative citability. Learn more about our complete AIO service.