# Study: Google AI Overviews cut Wikipedia search referrals 5%

Published: 2026-09-11T12:17:10.273Z · Source: Search Engine Journal (https://www.searchenginejournal.com/what-wikipedia-reveals-about-ai-overviews-and-web-traffic/589042/)
Source date: 2026-09-11
Entities: ai-overviews, google

A University of Washington paper estimates Google's AI Overviews cut monthly search referrals to English Wikipedia by roughly 5% since the feature became the US default in 2024, per authors Mehrzad Khosravi and Hema Yoganarasimhan, as reported by Search Engine Journal. Google disputes the estimate, saying Wikimedia's public referral data lumps together all search engines rather than isolating Google's; the authors counter that other engines carry too little traffic to explain the gap. An earlier draft of the same paper, using daily pageviews instead of monthly referrals, had put the decline near 15% before the authors revised downward after adding international controls.

Why it matters: It's one of the first non-vendor-funded estimates of AI Overviews' referral impact, and its own downward revision -- from roughly 15% to 5% -- shows how sensitive these figures still are to methodology.

## What this answers

**How much have Google AI Overviews reduced Wikipedia's search traffic?**

A University of Washington study estimates about a 5% decline in monthly search referrals to English Wikipedia since AI Overviews became Google's US default in 2024.

**Does Google dispute claims that AI Overviews reduced Wikipedia traffic?**

Yes -- Google says the Wikimedia referral data used in the study combines traffic from all search engines, making it impossible to isolate Google's effect specifically.


Canonical: https://anythingengineoptimization.com/item/2026-09-11-study-google-ai-overviews-cut-wikipedia-search-referrals-5/
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