Google's AI Mode and AI Overviews, as revealed by Ahrefs' recent report, can present answers with similar meanings but cite different sources. The study, published on the Ahrefs blog, analyzed U.S. data from September 2025, comparing responses from AI Mode and AI Overviews for 730,000 query pairs. The findings highlight a low overlap in cited URLs, with only 13% of responses sharing the same sources. However, when considering the top three citations, the overlap increases to 16%. The language in the responses also varies, with a 16% overlap in unique words and only 2.5% agreement on the exact first sentence. Despite these differences, Ahrefs reports strong semantic alignment, with an average score of 86%.
The report further reveals that AI Mode and AI Overviews have distinct preferences for sources. For instance, Wikipedia is cited more frequently in AI Mode (28.9%) compared to AI Overviews (18.1%). AI Mode also cites Quora 3.5 times more often and health sites at twice the rate of AI Overviews. In contrast, AI Overviews heavily rely on video content, with YouTube being the most cited source. Reddit, however, is cited at similar rates in both AI Mode and AI Overviews.
The analysis also highlights differences in entity and brand mentions. AI Mode responses are generally longer and include more entities, averaging 3.3 mentions compared to 1.3 in AI Overviews. Additionally, Ahrefs notes that a significant portion of responses in both AI Mode and AI Overviews lack mentions of persons or brands, which is associated with informational queries. The study also found that AI Mode is more likely to include citations, with only 3% of responses lacking sources, compared to 11% in AI Overviews.
The implications of these findings are significant for monitoring purposes. The low overlap in cited URLs and the differences in language and content suggest that AI Mode and AI Overviews may not always cite the same sources, even when they reach similar conclusions. This can impact how visibility is interpreted across different experiences. Google's documentation acknowledges the use of 'query fan-out' in both AI Overviews and AI Mode, which generates multiple related searches across subtopics and data sources. The varying models and techniques used by AI Mode and AI Overviews further emphasize the potential for different responses and links.
Ahrefs also notes that the analysis compares single generations of responses, and in related research, they found that 45.5% of AI Overview citations change when updated. This suggests that the overlap can vary across repeated runs. Despite this, the low overlap in the current dataset indicates a frequent selection of different URLs as supporting sources for the same query.
