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AI hallucinations are nothing new, but a recent investigation found that Google's AI Overviews search results have an accuracy rate of 90%. Although that's a high margin, it also means tens of millions of search results every hour are potentially flat-out wrong.
A report from The New York Times and AI startup Oumi found that one in 10 Google queries produced at least one summary with incorrect information, and in half of the cases where information was correct, there was a link to a source that didn't support the summary's claims.
Things have improved, but not by much. Oumi's analysis found that of the 4,326 searches conducted in October 2025, Gemini 2 produced accurate responses around 85% of the time. In February, when the same test was conducted using Gemini 3, accuracy improved to 91%.
Summary sourcing, however, degraded with Gemini 3. Oumi's data suggests that Gemini 2 produced erroneous source links 37% of the time last year, but now does it more than 56% of the time in 2026. Oumi suggests this may be because two of the most commonly cited sources by Gemini's AI summaries are Facebook and Reddit.
The NYT's report also showed how a BBC journalist used a deliberately misleading article they had created to poison the AI. Google's summary bot took the bait and, within 24 hours, repeated phony information from the source article.
Google disputes the results and notes that Oumi used the SimpleQA benchmark, an AI test developed by OpenAI that contains incorrect information in its own right. Google argues that the test doesn't reflect what people actually search for on Google and that summaries may differ for each search query. It also says Oumi uses its own AI systems to analyze the AI summaries, which could, in turn, lead to mistakes.
Although those points could be valid, it's also a pot-kettle situation. If your argument is that a report about your AI being inaccurate is wrong, because the company is trying to show it used AI that could be inaccurate, it doesn't exactly raise confidence in the accuracy of your AI.
Google's AI search summaries have been blamed for a downturn in publisher site traffic and job losses, which Google also disputes. More recently, the company has been using its AI to summarize headlines and news stories on Google Discover and Search, with questionable results.