Ahrefs study of AI citation stability finds half gone the next day

What changed

Ahrefs published a 20-day study of AI citation stability on 29 October 2026, following about 37,500 citations across Google AI Mode, ChatGPT, Google AI Overviews, Gemini and Copilot. Xibeijia Guan of Ahrefs asked the five AI tools the same questions every day, from 563 questions on Google AI Overviews to 3,173 on ChatGPT, and followed every website cited on day one.

Half or more of those citations were gone by the next day on every tool. Gemini and Copilot gave no citations in 64% and 53% of their answers, which pushed their losses higher, and with empty answers set aside all five tools lost 50 to 60%. The share of day-one citations gone by day two, by tool:

Google AI Overviews lost 50% of its citations overnight, Google AI Mode 58%, ChatGPT 59%, Gemini 81% and Copilot 83%.

Most lost citations came back. Roughly 75% of citations that disappeared at least once returned within the 20 days, and about half returned within three days. Citations that had lasted 8 to 14 days almost always returned, while 34 to 41% of one-day citations never did. “Don’t judge AI visibility from one check,” wrote Mateusz Makosiewicz, an SEO and marketing educator at Ahrefs.

Pages that ranked anywhere in Google for the same question were about seven times more likely to keep their AI citations for at least a week on Google AI Overviews and AI Mode. Ahrefs notes that the ranking analysis covered only 230 questions and that its findings are correlations.

Why it happened

Earlier studies had shown AI answers changing from one run to the next. On 17 July 2025, Profound reported that roughly 40 to 60% of cited domains were different a month later. On 28 January 2026, SparkToro put the chance that ChatGPT or Google’s AI repeats a brand list at less than 1 in 100. On 23 September 2026, Glen Allsopp’s study of over 70,000 responses found a steady core of brands with a tail that changes daily.

Ahrefs puts much of the churn where the tool picks pages. Query fan-out is a technique in which an AI tool runs several related searches before it answers, and Google’s guide to AI features says AI Overviews and AI Mode may use it. ChatGPT repeated the previous day’s searches only 26% of the time, and its cited websites changed 81% of the time even when the searches stayed the same.

What it changes for GEO

A one-day check of AI citations misjudges a brand’s position, because Ahrefs found half or more of the citations gone the next day and roughly 75% of those back within 20 days. Brands that buy GEO, or drop it, on one screenshot lose. Early numbers swing on small samples, so a GEO program needs about three months for a first verdict, even though a new page can show up in ChatGPT answers within days or weeks.

Each AI engine has to be judged on its own. Copilot lost 83% of its citations overnight in the Ahrefs study against 50% on Google AI Overviews, and on Gemini and Copilot a missing citation often means the answer cited nobody. One blended score across engines hides which engine dropped a brand.

A visibility number is only as honest as its frame. When a question named a brand, Ahrefs found the brand’s own website stayed cited all 20 days in roughly 30% of cases on Google’s AI tools and ChatGPT, four to seven times more often than the average cited website. A tracked set heavy on branded questions reports a stability that “best X” questions lack, since about 75% of their cited pages changed daily.

Search groundwork helps GEO, because retrieval begins with search indexes. Brands with pages ranking in Google for the buyer’s question gain, and Ahrefs’s July 2025 study of 1.9 million AI Overview citations found 86% came from pages in Google’s top 100. Brands whose cited pages do not rank lose, because those pages seldom keep a citation for a week:

Pages that ranked kept a citation for 7+ days 29% of the time on Google AI Overviews and 28% on AI Mode, against 4% for pages that did not rank. On ChatGPT the gap was smaller, 11% against 4%.

What to do

The head of marketing should ask whoever tracks AI visibility for a seven-day count: for each tracked question and each engine, the number of the last seven days on which the company’s site was cited. Teams that measure how often AI answers mention a brand should report branded questions and discovery questions such as “best X” separately.

On Gemini and Copilot, check whether the answer cited any source before counting a loss. Leave a page alone until its citation has been missing for two or three weeks, then check whether the page ranks in Google for that question, following how to get pages cited in Google AI Overviews. Judge the result by the seven-day count over several weeks, since Ahrefs found citations often disappear and return on their own.