Zombie stats: Where the numbers AI quotes come from

Trakkr Research asked ChatGPT, Perplexity, Gemini, Claude and Google AI Overviews 200 numeric questions, then traced 1,285 cited statistics up to five pages deep: 40% reached a study saying the same thing, 8% reached a study but with a changed number or context, 40% stopped at an unverifiable source and 11% led nowhere. Only 21% of pages cited for a number were the research itself, with more than half being company blogs, and four statistics (including "44% of salespeople give up after one follow-up") were quoted by all five assistants with no study behind them. On 31 of 71 questions where all five gave a percentage, the figures were 20 or more points apart.