In Citevio's run-consistency measurement on 12 August 2026, a two-run check across 16 buyer-intent agency-selection questions, not patient-facing dental queries, produced 64 valid answers from ChatGPT and Perplexity. ChatGPT gave the same headline answer on the flagged query in both runs. Perplexity's headline recommendation changed between runs. Two runs show instability exists; they do not tell you how often it happens.
A changed answer is not automatically evidence that something broke. This measurement tests a narrow question: whether repeated runs of the same buyer-intent agency-selection questions produced the same headline answer. It does not establish a change rate or explain an individual answer.
What did we find when we asked the same question twice?
In Citevio's run-consistency measurement on 12 August 2026, we took the same 16 buyer-intent agency-selection questions and ran each one twice on ChatGPT and twice on Perplexity. That produced 64 valid answers in total. These were agency-selection queries, not patient-facing dental queries, so this is a narrow read on repeated engine answers rather than a study of dental search.
| Engine | Runs | Result |
|---|---|---|
| ChatGPT | 2 | Stable: same headline answer on the flagged query in both runs |
| Perplexity | 2 | Unstable: headline recommendation changed from run 1 to run 2 |
Why does the same question give a different answer?
We did not measure the cause of the difference. Search-backed AI answers can draw on retrieval and ranking systems, but this measurement was not designed to isolate which system behavior changed an answer. It records the observed pattern only.
Why might I appear once and then disappear?
If a practice is named once and not named on a later check, the two-run result shows that a change is not automatically evidence that the practice did something wrong. Citevio has not measured which explanation applies to any individual case; that requires a targeted check of the specific question.
How do you tell a real change from noise?
In Citevio's run-consistency measurement on 12 August 2026, a single run was one data point. We used two runs per engine as the minimum check for whether a headline answer repeated or changed. Even two runs are not a change-rate measurement, so they are a basis for further checking, not a forecast.
Citevio's run-consistency measurement on 12 August 2026 used two runs per engine. They can show that an answer is unstable, but they cannot tell you how often it changes, and we do not publish a change rate we have not measured.
Do Google AI Overviews change the same way?
We measured run-to-run consistency on ChatGPT and Perplexity only. Our Gemini run returned a quota error on all 16 questions, and we have not measured AI Overviews, so for those two the honest answer is that we do not know. Google documents AI Overviews as a Search feature, but that does not tell us whether its output is more or less stable.
Which questions are commonly asked about changing AI answers?
How do I keep my site fresh so AI engines have something current to draw on?
There is no run-to-run consistency data tying update frequency to answer stability. Keep important facts current and available in text, but do not treat a content update as a guaranteed way to change an AI answer.
Does a different answer mean I did something wrong?
Not necessarily. In Citevio's run-consistency measurement on 12 August 2026, ChatGPT gave the same headline answer on the flagged query in both runs, while Perplexity's headline recommendation changed between run 1 and run 2. The measurement shows a change can occur; it does not identify the cause in an individual case.
Can you tell me how often my listing will change going forward?
No. Citevio's run-consistency measurement on 12 August 2026 used two runs per engine; those runs can show that an answer is unstable, but they cannot tell you how often it changes. We have not measured a change rate on any engine, and we do not publish one we have not measured.
Citevio's dental market research is published openly under CC-BY-4.0 with a DOI, so the numbers can be checked and reused; client data is never published.
Sources: OpenAI, ChatGPT search; Perplexity, What is Perplexity?; Google Search Central, AI features and your website; Citevio open dataset, Zenodo DOI 10.5281/zenodo.21833256; Citevio run-consistency measurement, 12 August 2026 (own data, methodology: how we measure AI visibility).
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