Google AI Overviews and Publisher Traffic: Evidence from a Field Experiment

Abstract

Online search engines depend on external content to respond to user queries, while content providers rely on search engines for visibility and user acquisition. The integration of GenAI-based summaries into search interfaces (eg, Google’s AI Overviews (AIOs)) may reduce users’ incentives to visit downstream publishers. Despite growing regulatory and industry attention, causal evidence on the effects of AI-generated summaries on search behavior remains limited. This paper provides causal evidence on the impact of AIOs on user behavior and downstream engagement using a field experiment that randomly assigns users to either the standard Google Search experience with AIOs or a version where AIOs are removed. We develop a custom Chrome browser extension that passively tracks detailed browsing behavior while also enabling real-time modifications to the search engine results page (SERP), allowing us to precisely manipulate AIO exposure in a natural browsing environment. When they appear, AIOs reduce outbound organic clicks by 38% and increase the probability of a zero-click search by 33%. We find no effects on sponsored clicks or overall search frequency, implying that AIOs reduce total external traffic by lowering organic clicks per search. Heterogeneity analyses show that effects are concentrated when AIOs appear at the top of the page and among the highest-ranked organic results. Using survey evidence, we find that despite these behavioral effects, removing AIOs does not affect users’ overall search experience, including perceived ease of finding information and the quality of results. Exploratory evidence from a third AI Mode condition, where users are redirected to a Gemini-powered conversational AI interface, suggests even stronger reductions in engagement with downstream publishers. Overall, the findings suggest that AIOs divert traffic away from publishers without delivering measurable improvements in user experience, raising important implications for competition policy, platform power, and publisher sustainability

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