Study: Google AI Overviews Cut Wikipedia's Search Traffic by 100 Million Clicks Monthly

A draft study by University of Washington researchers Mehrzad Khosravi and Hema Yoganarasimhan estimates that Google's AI Overviews feature reduced English Wikipedia's search-referred traffic by roughly 5 percent per month after the feature became default in the United States in May 2024. Translated into absolute numbers, that decline amounts to approximately 100 million fewer visits per month, or around 1.2 billion per year. Researchers compared English Wikipedia traffic against German and French editions — where AI Overviews were not yet default — using nearly 500,000 matched article pairs and data spanning December 2023 to December 2024. Google disputed the findings, arguing that Wikimedia's public data bundles all search engines together, making it impossible to isolate Google's specific effect; the research team countered that rival search engines account for only a small share of traffic. The paper remains an unreviewed draft, last revised on 2 September 2026, and its authors caution that the results apply specifically to Wikipedia and cannot be directly generalised to news sites, e-commerce, or other web categories.