Google’s AI Mode and AI Overviews can produce answers with similar meaning while citing different sources, according to new data from Ahrefs.
The report, published on the Ahrefs blog, analyzed September 2025 U.S. data from Ahrefs’ Brand Radar tool and compared AI Mode and AI Overview responses for the same queries.
The authors looked at 730,000 query pairs for content similarity and 540,000 query pairs for citation and URL analysis.
What The Study Found
Ahrefs reports that AI Mode and AI Overviews cited the same URLs only 13% of the time. When comparing only the top three citations in each response, overlap increased to 16%.
The language in the responses also varied. Ahrefs reports 16% overlap in unique words and states that AI Mode and AI Overviews share the exact same first sentence only 2.5% of the time.
Ahrefs reported strong semantic alignment, with an average semantic similarity score of 86%, and 89% of response pairs scoring above 0.8 on a scale where 1.0 indicates identical meaning.
Despina Gavoyannis, Senior SEO Specialist at Ahrefs, writes:
“Put simply: 9 out of 10 times, AI Mode and AI Overview agreed on what to say. They just said it differently and cited different sources.”
Different Source Preferences
Ahrefs reports differences in which websites and content types each feature tends to cite.
For example, Wikipedia appears in 28.9% of AI Mode citations compared to 18.1% in AI Overviews. The data also finds that AI Mode cited Quora 3.5x more often and cited health sites at roughly double the rate of AI Overviews.
AI Overviews, by contrast, leaned more heavily on video content. YouTube was the most frequently cited source for AI Overviews, whereas Reddit was cited at similar rates in both AI Mode and AI Overviews.
Ahrefs also reports that AI Overviews cited videos and core pages (such as homepages) nearly twice as often as AI Mode. At the same time, both features showed a strong preference for article-format pages overall.
Entity And Brand Mentions
Ahrefs found AI Mode responses were about four times longer than AI Overviews on average and included more entities.
In the dataset, AI Mode averaged 3.3 entity mentions per response compared to 1.3 for AI Overviews. Approximately 61% of the time, AI Mode included all entities mentioned in the AI Overview response and then added additional entities.
Many responses didn’t include brands or entities. Ahrefs reports that 59.41% of AI Overview responses and 34.66% of AI Mode responses contained no mentions of persons or brands, which the authors associate with informational queries in which named entities are not typically part of the answer.
Citation Gaps
The data finds that AI Mode was more likely to include citations than AI Overviews.
Only 3% of AI Mode responses lacked sources, compared to 11% of AI Overviews. Ahrefs reports that missing citations typically occur in cases such as calculations, sensitive queries, help center redirects, or unsupported languages.
Why This Matters
This report suggests that AI Mode and AI Overviews can differ in the sources they credit, even when they reach similar conclusions for the same query.
For monitoring purposes, this can affect how you interpret “visibility” across experiences. A citation (or a mention) in AI Overviews does not necessarily imply you will be cited in AI Mode for the same query, and AI Mode’s longer responses may include additional entities and competitors compared to the shorter AI Overview format.
Google’s documentation states that both AI Overviews and AI Mode may use “query fan-out,” which issues multiple related searches across subtopics and data sources while a response is being generated.
Google also notes that AI Mode and AI Overviews may use different models and techniques, so the responses and links they display will vary.
Looking Ahead
Ahrefs notes this analysis compares single generations of AI Mode and AI Overview responses. In related research, Ahrefs reported that 45.5% of AI Overview citations change when AI Overviews update, suggesting that overlap can appear different across repeated runs.
Even with that caveat, the low overlap observed in this dataset indicates that AI Mode and AI Overviews frequently select different URLs as supporting sources for the same query.
Featured Image: hafakot/Shutterstock
