Only 40% of AI-cited statistics trace back to a study

In a study of 1,285 statistics cited by major AI assistants (ChatGPT, Perplexity, Gemini, Claude, and Google AI Overviews), researchers found that only 40% could be traced back to an actual study supporting the claim. Another 8% reached a study but with altered numbers or context, while 51% either led to unchecked sources or dead ends, revealing widespread reliance on unverified "zombie statistics" that circulate with false confidence across AI systems.