Repeated Gemini queries produced different citation sets in a local-search study

A local-search study found that Gemini often cited different domains when researchers repeated a question. A single result remains useful evidence of what happened in that run. It is much weaker evidence of what customers will consistently see.

What the study compared

A citation is a link the assistant shows next to its answer, pointing at a page it read while writing that answer. It matters commercially because being one of those links is how a business gets seen inside an AI answer, now that many people never scroll to the ten blue links underneath.

The other term you need is the local pack: the boxed set of three nearby businesses Google shows for something like “plumber near me”. It has been the benchmark for local search for years, and provides a conventional-search comparison for this study.

What the study actually did

Steady Demand, a local SEO agency, ran 1,487 local-service queries across all 50 US metro areas and ten categories: plumber, roofer, HVAC, electrician, locksmith, pest control, cleaning, lawyer, dentist, auto repair. That produced 14,472 citations, collected on 27 and 28 July 2026. Gemini was queried through the API as gemini-flash-latest with Google Search grounding switched on. ChatGPT was captured through a scraper hitting its consumer Search mode. Search Engine Land covered the findings on 19 August.

In the broader dataset, almost 60% of Gemini’s local citations pointed at the business’s own website. Reddit accounted for 13.7%; local-service directories together accounted for 10.3%. Business websites were therefore an important source within this sample.

A smaller follow-up test repeated selected questions.

The repeat test

Six fixed queries, four rounds, same wording every time. 72 calls in total. That is a small sample and the authors say so, along with the rest of their stated limitations: one snapshot in time, API behaviour that may not match what a consumer sees in the app, US only.

The overlap between rounds was measured with a similarity score where 100% means the two lists of cited domains are identical and 0% means they share nothing. The results:

• Back-to-back, same day: 46.3%
• Same day, 3.5 hours later: 41.0%
• Next day, 19 to 20 hours later: 26.5%

Rephrased queries also produced overlap around 40%. With only six fixed queries in the repeat test, the results do not establish a general rate of change or isolate a single cause.

The researchers also observed variation in the generated search queries. Before answering, the model writes its own search queries and sends those to Google. On back-to-back repeats those internally generated search strings overlapped by 0.056 on the same scale. Essentially not at all. That is one plausible contributor to different citation sets, although the observations do not isolate every retrieval and selection step. Steady Demand calls it grounding drift.

The comparison that makes it concrete: asked repeatedly, Gemini named the same top business 7.9% of the time. Google’s local pack, asked the same thing, returned the same top listing 90.2% of the time. The AI answers varied more than the local-pack results in this test.

The two engines are not reading the same web

The same 1,487 queries went to both engines. Their cited domains overlapped 8% of the time on average. They recommended the same top business in 4.2% of cases.

The two datasets also had different source mixes. Gemini’s citations were 59.9% business websites. ChatGPT’s were 15.9% business websites and 41.7% social and community forums. This is a difference in the sampled citations, not a complete description of what either system reads.

What to do about it

Treat a single check as one observation. A set-overlap score is not the probability of an identical answer, so it should not be described as a coin flip. Run the same prompts on a schedule and report the trend across many samples, which is the same argument for measuring rather than estimating we have made before.

Measure each engine separately. At 8% overlap, “AI visibility” as a single number averages away the only thing that is actionable.

Also keep the client’s pages accurate and accessible. Gemini’s mix says the business site is the single largest source of local citations, so the ordinary work of accurate, crawlable, well-structured pages is still the work.