Data Studies
Research on how ChatGPT, Gemini, Perplexity, Google AI Mode and Google AI Overviews answer the questions your customers ask: which brands they name, which pages they cite and link to, and where they send shoppers. Most studies are built on thousands of answers we collect from those engines, including the web searches ChatGPT runs behind the scenes. Many compare those answers with Google search and Google Maps results, Google Business Profiles, Google News, or robots.txt files from the public HTTP Archive crawl. Use them to see where AI answers pull from in your market.
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When AI engines answer "what is the best..." travel questions, most of them about travel credit cards, Chase is the first brand named in 51.9% of answers. No brand in any of 20 shopping categories leads by as much, and in beauty the top brand is named first in 11.1% of answers.
In 14 of 20 product and service categories, ChatGPT, Gemini, Google AI Mode and Perplexity each put at least two of the same three brands in their own top three. In four categories, all four engines have exactly the same top three.
Google's AI Overviews cite a YouTube video in 67.5% of their answers to "what is the best..." shopping questions. Across five AI engines, YouTube is the most-cited review source at 24.9% of answers, ahead of Reddit (14.7%) and Forbes (14.4%), but each engine trusts a different reviewer.
Brands in the top quarter for web and news coverage are named in 13.4 times as many AI answers as brands in the bottom quarter: 220.8 answers each on average, against 16.5. The typical least-covered brand appears in 2 AI answers out of 56,068.
Ask Gemini "Is [brand] good?" twice and it brings up complaints, lawsuits, recalls or similar negatives for 72.6% of brands. ChatGPT does the same for 57.2% of brands, and for auto dealers 72% of its answers carry a negative word.
32.2% of the 500 brands whose websites rank most often in Google search are not named in a single one of 56,068 AI answers. At the top of the AI Visibility Index, Walmart is named in 1,315 answers, followed by Capital One and American Express.
Brands that block GPTBot, the bot OpenAI uses to collect web pages, are named in 31.5 ChatGPT answers on average, against 20.7 for brands that allow it, 52% more. Blocking OpenAI does not take a brand out of ChatGPT's answers; it goes with fewer links to the brand's own pages.
27% of the brand websites ChatGPT recommends and links to in its answers showed no paid Google keywords in September 2026, including purina.com, cerave.com and trello.com. Their place in ChatGPT's answers did not depend on search ads.
Google's AI Overviews cite Reddit in 23.5% of their answers, while ChatGPT cites it in 0.1%, a 176-fold gap. Across five AI engines, Reddit appears in 11.8% of answers to everyday questions, about one in eight.
ChatGPT links to Wikipedia in 2.7% of its answers to everyday questions, fewer than three in a hundred. Perplexity cites Wikipedia in 23.1% of answers and Google's AI Overviews in 19.4%, so the encyclopedia's reach in AI depends on the engine.
54.9% of Google's AI Overviews that list sources cite at least one YouTube video, and YouTube supplies 14.8% of all AI Overview citations, six times as many as Reddit. For roofing searches, 86.7% of AI Overviews cite a YouTube video.
66.2% of Google AI Overviews with sources link to at least one Google-owned website, such as YouTube or a Google Shopping page, and Google's own properties take 27.2% of every source link the AI Overviews show.
Publishers with announced OpenAI content deals receive 24.3% of ChatGPT's citations when it answers news questions, 2.2 times their 11.2% share of Google News results for the same questions.
45% of answers from ChatGPT, Gemini and Google AI Mode cite at least one web page published more than two years earlier, and 57.8% cite one more than a year old. ChatGPT leans on old pages most, in 46.5% of its answers.
27.8% of the sources in Google's AI Overviews are user-generated platforms such as YouTube, Facebook and Reddit, against 0.2% of ChatGPT's sources. Across five AI engines, about one citation in eight is user-generated, and most of it is video and social media, not forums.
YouTube is the most-cited website in AI answers, and almost all of that comes from Google: Google AI Overviews cites YouTube 6,894 times, while ChatGPT cites it 5 times on the same 2,984 questions. Across ChatGPT, Gemini, Perplexity and Google's AI features, YouTube appears in 20.1% of all answers, ahead of Reddit and Wikipedia.
When people ask Gemini "Is [brand] good?", 21.3% of its sourced answers cite the website of one of that brand's competitors. Across ChatGPT and Gemini, 11% of answers about what a brand is and whether it is good cite a rival's site, and 46% of "Is it good?" answers leave out the brand's own website.
47% of the news websites Google News shows most often block GPTBot, the crawler OpenAI uses to collect training material for ChatGPT, against 17.6% of all news publisher websites. Far fewer block the bots ChatGPT uses to fetch and cite pages when it answers.
Reuters is cited in more AI answers to news questions than any other outlet, 328 in all, 250 of them from ChatGPT. Each AI engine has its own favorite newsrooms, from wire services on ChatGPT to finance outlets on Google AI Mode.
Paywalls are no barrier to AI citations: 16.7% of AI answers that cite a news outlet include a paywalled one, about one in six. Which paywalled outlets get cited depends on the engine, from the Wall Street Journal on Google AI Mode to the Los Angeles Times on ChatGPT.
YouTube is the most-cited website in AI answers to health questions, appearing in 28.4% of sourced answers, ahead of the US National Institutes of Health at 26.7%. Overall, 67% of sourced AI health answers cite a government or medical source, but the rate ranges from 76.1% on ChatGPT to 33.6% on Gemini.
8.1% of answers from ChatGPT, Gemini and Google's AI features to health, nutrition, mental health and sleep questions use a standard referral phrase such as "see a doctor", "talk to your healthcare provider" or "call 988". The count covers these standard phrases, so answers can point to care in other words as well. Gemini uses them in 10.4% of its health answers and ChatGPT in 5%.
Perplexity cites a comparison site such as NerdWallet or Bankrate in 93% of its answers about credit cards and loans, against 21.4% for ChatGPT, which leans on the government's consumerfinance.gov and bank websites instead. Across five AI engines, 59% of sourced credit card and loan answers cite at least one comparison site.
When people ask ChatGPT, Gemini or Google's AI features about federal tax, 76.4% of the answers cite irs.gov. Questions about state, sales and property tax, which the IRS does not cover, draw on tax software companies, a tax policy nonprofit and national publishers, and TurboTax's maker Intuit appears in more AI tax answers than any state revenue department.
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