ChatGPT, Google AI Overviews split on health authority sources
ChatGPT’s top five cited domains for health questions are all government agencies or hospital systems, with YouTube absent from its top ten, while Google AI Overviews’ YouTube citations run 1.8x above their June level and outrank clinical sources, according to a BrightEdge analysis using its AI Hyper Cube citation tracking. For finance questions, BrightEdge found Google AI Overviews concentrates citations in a single leading source (51% of tracked prompts) far more than ChatGPT, whose top five sources run 19%, 15%, 14%, 14%, and 11% and include the smaller valuation platform SimplyWall.st.
Why it matters: The two engines are applying different definitions of authority to the same YMYL categories, so a source's realistic shot at citation depends on which engine it's optimizing for, not just what it publishes.
The record: Google AI OverviewsChatGPT
Glossary: AI Overviews
Posted to the wire August 31, 2026.