Signal Who Anchors AI Overviews in Health? Baidu, Google, and the Geography of Authority

Summary

As AI is rapidly incorporated into search systems, this study addresses the scant auditing of information disparities across platforms, geography, and language by comparing Google's and Baidu's AI Overview systems for health queries and measuring the informational anchors that emerge. Auditing 1,920 health queries across 12 countries and 4 languages, the authors find that both Google and Baidu exhibit vertical integration, routing users toward their own company platforms rather than a diverse set of primary sources. Smaller, lower-localization countries receive fewer domestically sourced references for health queries, and issuing the same query in a country's official language rather than English raises the share of locally sourced citations approximately 3.5- to 13.5-fold. Comparing queries across health topics of varying severity and controversy, including Traditional Chinese Medicine, the study also shows that health disclaimers are multidimensional and vary across language and culture. The authors discuss how generative search influences access to health information and the need for culturally-aware oversight of systems that influence critical health decisions.