Research on AI search, with the data attached
Original measurement rather than recycled advice. Every study here ships with its methodology, its limitations, and wherever possible the raw data — so you can check the numbers instead of taking them on trust.
Featured
The state of AI search: September 2026
A snapshot of where AI-search research actually stands as this site's research program launches. Five findings, five unanswered questions, and an honest inventory.
AI search CTR statistics
How click-through behavior changes when an AI Overview appears. The specific population each figure describes stays attached, not stripped away.
Everything else
The AI citation dataset strategy
Every dataset this site plans to publish, in one place: what it contains, when it ships, how it is licensed. Raw files, not just summary reports.
What is AI SEO?
The umbrella term for optimizing a site's visibility across the whole AI-search landscape: generative answers, AI crawlers, and the technical infrastructure behind both.
What is GEO?
Optimizing content so AI systems like ChatGPT, Perplexity and Gemini cite it when generating an answer. That is Generative Engine Optimization.
AI search glossary
Definitions for the terms used throughout this site's research. Kept tight, each linked to the fuller page where the concept is explored.
AI SEO statistics
Every AI-search statistic on this site, in one table, each with a verification grade and a link to full context.
AEO statistics
Answer Engine Optimization statistics. Genuinely fewer exist under this specific label than under GEO, and this page says so rather than padding itself.
GEO statistics
The most commonly cited Generative Engine Optimization statistics, each with a verification status attached rather than uniform, unearned confidence.
The Null-Results Registry
Every pre-registered prediction on this site that is, or is predicted to be, a null result, tracked in one place. Almost nobody publishes negative findings.
AI search and YMYL content: what is actually known
Health, finance, legal and safety queries carry higher stakes. Do AI engines cite differently for them? That is an open, under-studied question.
Local AI search: what is actually known
Local intent is a large share of all search behavior. Rigorous AI-search research on it is almost entirely absent. Stated plainly, not filled with a borrowed number.
Open-source SEO agent tooling: what to build
The citation-collection harness, log-analysis pipeline and audit agents behind this site's own research are more credible open than closed.
Claude Code SEO failure modes
Where agentic SEO work actually goes wrong. Almost all existing coverage is promotional. This is the first-party failure catalogue instead.
Claude Code for SEO: the complete guide
Using Claude Code as an execution agent for technical SEO: audits, schema generation, structural fixes, log analysis. With a worked example and safety practices.
AI shopping and agentic commerce statistics
AI agents are beginning to complete purchases on a shopper's behalf. What is actually measured, and how much of the coverage is still forecast rather than fact.
WebMCP and the agent-readable web
Google and Microsoft shipped an early preview of a structured agent-interaction protocol for websites in Feb 2026. What it is, and why site owners should care now.
MCP servers as a visibility channel
The Model Context Protocol lets AI agents query a business data directly. Does publishing one affect AI-search visibility? Untested, but genuinely early.
Agentic browsers: what do they actually fetch?
ChatGPT Atlas, Perplexity Comet and Gemini in Chrome are shipping now. What they actually request from a page has barely been studied. Pre-registered.
Do AI crawlers render JavaScript?
Retrieval bots may not execute client-side JavaScript. If not, any content that depends on it is invisible to them entirely. Pre-registered experiment.
AI Mode vs. AI Overviews: source delta
Two distinct Google AI surfaces, routinely treated as interchangeable. Do they actually cite the same sources for the same query? Pre-registered study.
The Reddit dependency: what Perplexity cites when Reddit has nothing
Perplexity's citations skew heavily to Reddit. For B2B and enterprise topics with thin discussion, what fills the gap? Pre-registered study.
The Wikipedia dependency: what ChatGPT cites when Wikipedia has nothing
ChatGPT's citations skew heavily to Wikipedia. For topics it doesn't cover well, what fills the gap? Pre-registered study.
Brand mentions vs. backlinks: which predicts AI citation?
Reported correlations put brand mentions at roughly 3x the predictive strength of backlinks for AI Overview visibility. A confound nobody has controlled for.
Does an author bio affect AI citation?
Author credentials and E-E-A-T signals are recommended constantly. No controlled test isolates whether they change AI citation rate. A pre-registered RCT.
Does content freshness increase AI citations?
'Keep content updated' is universal GEO advice. No controlled study has tested it against citation rate. A pre-registered RCT.
Crawl-to-citation latency
How many days pass between an AI crawler first fetching a new page and that page appearing in a citation? Pre-registered panel study.
The Query Fan-Out Corpus
Everyone repeats that Google AI Mode fans a query into '8-16 sub-queries.' Nobody has published the data behind that number. A pre-registered corpus design.
Cross-platform citation concordance
How much do ChatGPT, Perplexity, Gemini, Claude and Google agree on what to cite? A reported ~11% two-engine overlap suggests: not much. Pre-registered study.
AI citation half-life: how long do citations last?
Once a URL is cited by an AI engine, how long does it stay cited? Nobody has measured this. A 12-month tracking study, pre-registered.
Does schema markup increase AI citations?
The most contested tactic in GEO. This page registers a randomized test to settle it. Pre-registered before a single page is enrolled.
AI search conversion benchmarks
Published claims about AI traffic conversion range from 4.4x to 23x organic. Different orders of magnitude. Here is why, and the honest version of the statistic.
AI referral traffic statistics
How much traffic AI platforms actually send to websites, how it splits between engines, and why standard analytics likely undercount it.
Zero-click search statistics
The most commonly quoted zero-click figures, each attached to the specific population it actually measures. Collapsing them into one number is where most content goes wrong.
AI search market share statistics
How traffic is distributed across AI search platforms, how that's shifted over the past year, and how AI referral engagement compares to classic organic.
Gemini citation statistics
Gemini, AI Overviews, and AI Mode are three related but distinct Google surfaces, routinely conflated in coverage. What is actually known about Gemini specifically.
Perplexity citation statistics
Perplexity is the most transparent of the major AI search engines about its sources. Its citation pattern looks meaningfully different from ChatGPT.
Claude citation statistics
What is actually known about what Claude cites, and an honest accounting of how much isn't known. Claude is the least-studied major AI search surface.
ChatGPT citation statistics
What ChatGPT actually cites, how it retrieves information, and how weakly Google ranking predicts showing up in a ChatGPT Search answer.
Most-cited domains in AI search
Which kinds of sources dominate citations across ChatGPT, Perplexity and Google AI Overviews. And how little the major engines actually agree with each other.
Google AI Mode statistics and query fan-out, explained
How AI Mode actually retrieves information: the query fan-out mechanism, its documented patent basis, and what is confirmed versus estimated.
Google AI Overview statistics
Trigger rates, citation-to-ranking overlap, and click-through impact for AI Overviews - with a verification status attached to every figure.
The AI Visibility Measurement Standard
'AI visibility' currently means whatever a vendor's dashboard measures. A proposed open specification so numbers from different sources become comparable.
GEO vs AEO vs LLMO: which term is winning
Three acronyms describe overlapping ideas about optimizing for AI-generated answers. The industry hasn't settled on one. What each means, where they overlap, and which is gaining ground.
The GEO Tactic Evidence Scoreboard
Every tactic the industry recommends for getting cited by AI search, graded by the actual evidence behind it. Not by how often it is repeated.
The robots.txt AI-Blocking Census
How many of the web's most important sites block AI crawlers, measured directly from robots.txt, not quoted from a report with no visible sample. Pre-registration.
AI crawler statistics
How much of the web's bot traffic is AI. Which crawlers take the most relative to what they give back, and how that's shifted year over year. Verification status on every figure.
The AI Bot User-Agent Registry
Every AI crawler that matters for a website owner in one place: what it's for, how to verify it, and what to put in robots.txt. Maintained, not a one-off listicle.
Where AI SEO statistics actually come from
We traced twelve of the most-quoted numbers in AI search back to their origin. Five hold up. Three dead-end. The most-repeated figure in the field is three studies wearing one number.
The AI Citation Index
A quarterly, open measurement of what seven AI search engines actually cite. Query set, raw data and methodology published in full. This is the pre-registration.
Zero to Cited: how a new site climbs into AI search
The evidence-backed timeline and playbook for taking a brand-new site from launch to its first citations in Bing, Perplexity, ChatGPT and AI Overviews.
Bing Copilot SEO: the easiest AI engine to crack
ChatGPT search runs on Bing's index. Getting into Bing is the fastest path to your first AI citation. Here's the full playbook.
Does llms.txt actually work? A 90-day log test
I deployed llms.txt and read the server logs for 90 days. Here is what the data, and the largest studies, actually say.
GPTBot vs OAI-SearchBot: the AI crawler guide
The most-confused pair in AI SEO. One is a training crawler, one gets you cited. Plus every other AI bot and exactly what to allow or block.
How to get cited by ChatGPT: 9 tactics, with data
The Princeton-backed levers - statistics, quotes, structure, freshness - that actually move AI citations.
The 50-point technical GEO audit
A complete technical checklist to make a site under 500 pages fully legible to Google, Bing and the AI answer engines.
Where to go deeper
GEO / AI Search
Getting cited by ChatGPT, Perplexity, Gemini & AI Overviews.
The AI citation dataset strategy
Every dataset this site plans to publish, in one place: what it contains, when it ships, how it is licensed. Raw files, not just summary reports.
What is AI SEO?
The umbrella term for optimizing a site's visibility across the whole AI-search landscape: generative answers, AI crawlers, and the technical infrastructure behind both.
What is GEO?
Optimizing content so AI systems like ChatGPT, Perplexity and Gemini cite it when generating an answer. That is Generative Engine Optimization.
AI search glossary
Definitions for the terms used throughout this site's research. Kept tight, each linked to the fuller page where the concept is explored.
AI SEO statistics
Every AI-search statistic on this site, in one table, each with a verification grade and a link to full context.
AEO statistics
Answer Engine Optimization statistics. Genuinely fewer exist under this specific label than under GEO, and this page says so rather than padding itself.
GEO statistics
The most commonly cited Generative Engine Optimization statistics, each with a verification status attached rather than uniform, unearned confidence.
The Null-Results Registry
Every pre-registered prediction on this site that is, or is predicted to be, a null result, tracked in one place. Almost nobody publishes negative findings.
WebMCP and the agent-readable web
Google and Microsoft shipped an early preview of a structured agent-interaction protocol for websites in Feb 2026. What it is, and why site owners should care now.
MCP servers as a visibility channel
The Model Context Protocol lets AI agents query a business data directly. Does publishing one affect AI-search visibility? Untested, but genuinely early.
The AI Visibility Measurement Standard
'AI visibility' currently means whatever a vendor's dashboard measures. A proposed open specification so numbers from different sources become comparable.
GEO vs AEO vs LLMO: which term is winning
Three acronyms describe overlapping ideas about optimizing for AI-generated answers. The industry hasn't settled on one. What each means, where they overlap, and which is gaining ground.
The GEO Tactic Evidence Scoreboard
Every tactic the industry recommends for getting cited by AI search, graded by the actual evidence behind it. Not by how often it is repeated.
Bing Copilot SEO: the easiest AI engine to crack
ChatGPT search runs on Bing's index. Getting into Bing is the fastest path to your first AI citation. Here's the full playbook.
How to get cited by ChatGPT: 9 tactics, with data
The Princeton-backed levers - statistics, quotes, structure, freshness - that actually move AI citations.
Technical SEO
Schema, llms.txt, crawlers, IndexNow - the plumbing AI reads.
Open-source SEO agent tooling: what to build
The citation-collection harness, log-analysis pipeline and audit agents behind this site's own research are more credible open than closed.
Claude Code SEO failure modes
Where agentic SEO work actually goes wrong. Almost all existing coverage is promotional. This is the first-party failure catalogue instead.
Claude Code for SEO: the complete guide
Using Claude Code as an execution agent for technical SEO: audits, schema generation, structural fixes, log analysis. With a worked example and safety practices.
AI crawler statistics
How much of the web's bot traffic is AI. Which crawlers take the most relative to what they give back, and how that's shifted year over year. Verification status on every figure.
The AI Bot User-Agent Registry
Every AI crawler that matters for a website owner in one place: what it's for, how to verify it, and what to put in robots.txt. Maintained, not a one-off listicle.
GPTBot vs OAI-SearchBot: the AI crawler guide
The most-confused pair in AI SEO. One is a training crawler, one gets you cited. Plus every other AI bot and exactly what to allow or block.
The 50-point technical GEO audit
A complete technical checklist to make a site under 500 pages fully legible to Google, Bing and the AI answer engines.
Data & Studies
Original experiments and numbers you can't get elsewhere.
The state of AI search: September 2026
A snapshot of where AI-search research actually stands as this site's research program launches. Five findings, five unanswered questions, and an honest inventory.
AI search CTR statistics
How click-through behavior changes when an AI Overview appears. The specific population each figure describes stays attached, not stripped away.
AI search and YMYL content: what is actually known
Health, finance, legal and safety queries carry higher stakes. Do AI engines cite differently for them? That is an open, under-studied question.
Local AI search: what is actually known
Local intent is a large share of all search behavior. Rigorous AI-search research on it is almost entirely absent. Stated plainly, not filled with a borrowed number.
AI shopping and agentic commerce statistics
AI agents are beginning to complete purchases on a shopper's behalf. What is actually measured, and how much of the coverage is still forecast rather than fact.
Agentic browsers: what do they actually fetch?
ChatGPT Atlas, Perplexity Comet and Gemini in Chrome are shipping now. What they actually request from a page has barely been studied. Pre-registered.
Do AI crawlers render JavaScript?
Retrieval bots may not execute client-side JavaScript. If not, any content that depends on it is invisible to them entirely. Pre-registered experiment.
AI Mode vs. AI Overviews: source delta
Two distinct Google AI surfaces, routinely treated as interchangeable. Do they actually cite the same sources for the same query? Pre-registered study.
The Reddit dependency: what Perplexity cites when Reddit has nothing
Perplexity's citations skew heavily to Reddit. For B2B and enterprise topics with thin discussion, what fills the gap? Pre-registered study.
The Wikipedia dependency: what ChatGPT cites when Wikipedia has nothing
ChatGPT's citations skew heavily to Wikipedia. For topics it doesn't cover well, what fills the gap? Pre-registered study.
Brand mentions vs. backlinks: which predicts AI citation?
Reported correlations put brand mentions at roughly 3x the predictive strength of backlinks for AI Overview visibility. A confound nobody has controlled for.
Does an author bio affect AI citation?
Author credentials and E-E-A-T signals are recommended constantly. No controlled test isolates whether they change AI citation rate. A pre-registered RCT.
Does content freshness increase AI citations?
'Keep content updated' is universal GEO advice. No controlled study has tested it against citation rate. A pre-registered RCT.
Crawl-to-citation latency
How many days pass between an AI crawler first fetching a new page and that page appearing in a citation? Pre-registered panel study.
The Query Fan-Out Corpus
Everyone repeats that Google AI Mode fans a query into '8-16 sub-queries.' Nobody has published the data behind that number. A pre-registered corpus design.
Cross-platform citation concordance
How much do ChatGPT, Perplexity, Gemini, Claude and Google agree on what to cite? A reported ~11% two-engine overlap suggests: not much. Pre-registered study.
AI citation half-life: how long do citations last?
Once a URL is cited by an AI engine, how long does it stay cited? Nobody has measured this. A 12-month tracking study, pre-registered.
Does schema markup increase AI citations?
The most contested tactic in GEO. This page registers a randomized test to settle it. Pre-registered before a single page is enrolled.
AI search conversion benchmarks
Published claims about AI traffic conversion range from 4.4x to 23x organic. Different orders of magnitude. Here is why, and the honest version of the statistic.
AI referral traffic statistics
How much traffic AI platforms actually send to websites, how it splits between engines, and why standard analytics likely undercount it.
Zero-click search statistics
The most commonly quoted zero-click figures, each attached to the specific population it actually measures. Collapsing them into one number is where most content goes wrong.
AI search market share statistics
How traffic is distributed across AI search platforms, how that's shifted over the past year, and how AI referral engagement compares to classic organic.
Gemini citation statistics
Gemini, AI Overviews, and AI Mode are three related but distinct Google surfaces, routinely conflated in coverage. What is actually known about Gemini specifically.
Perplexity citation statistics
Perplexity is the most transparent of the major AI search engines about its sources. Its citation pattern looks meaningfully different from ChatGPT.
Claude citation statistics
What is actually known about what Claude cites, and an honest accounting of how much isn't known. Claude is the least-studied major AI search surface.
ChatGPT citation statistics
What ChatGPT actually cites, how it retrieves information, and how weakly Google ranking predicts showing up in a ChatGPT Search answer.
Most-cited domains in AI search
Which kinds of sources dominate citations across ChatGPT, Perplexity and Google AI Overviews. And how little the major engines actually agree with each other.
Google AI Mode statistics and query fan-out, explained
How AI Mode actually retrieves information: the query fan-out mechanism, its documented patent basis, and what is confirmed versus estimated.
Google AI Overview statistics
Trigger rates, citation-to-ranking overlap, and click-through impact for AI Overviews - with a verification status attached to every figure.
The robots.txt AI-Blocking Census
How many of the web's most important sites block AI crawlers, measured directly from robots.txt, not quoted from a report with no visible sample. Pre-registration.
Where AI SEO statistics actually come from
We traced twelve of the most-quoted numbers in AI search back to their origin. Five hold up. Three dead-end. The most-repeated figure in the field is three studies wearing one number.
The AI Citation Index
A quarterly, open measurement of what seven AI search engines actually cite. Query set, raw data and methodology published in full. This is the pre-registration.
Zero to Cited: how a new site climbs into AI search
The evidence-backed timeline and playbook for taking a brand-new site from launch to its first citations in Bing, Perplexity, ChatGPT and AI Overviews.
Does llms.txt actually work? A 90-day log test
I deployed llms.txt and read the server logs for 90 days. Here is what the data, and the largest studies, actually say.
One experiment. Every week.
The field notes in your inbox - one thing I tested, the raw numbers behind it, and what it means for getting cited by AI.