Earlier quoted context omitted.
Google actually has the BEST ratings in the AA-Omniscience Index: AA-Omniscience Index (higher is better) measures knowledge reliability and hallucination. It rewards correct answers, penalizes hallucinations, and has no penalty for refusing to answer. Gemini 3.1 is the top spot, followed by 3.0 and then opus 4.6 max
This isn't actually correct. Gemini 3.0 gets a very high score because it's very often correct, but it does not have a low hallucination rate. https://artificialanalysis.ai/#aa-omniscience-hallucination-... It looks like 3.1 is a big improvement in this regard, it hallucinates a lot less.
In short, its hallucination rate as a percentage of unknown answers is no better than most models, but its hallucination rate as a percentage of total answers in indeed better.