Google’s AI Mode generates responses that are 4x longer than AI Overviews (on average). When we first noticed this, the natural assumption was that AI Mode simply expands on the same information, taking AI Overview’s concise answer and adding more detail from the same sources.

But after analyzing 730,000 response pairs, we found something unexpected: AI Mode and AI Overviews reach very similar conclusions (86% semantic similarity) while citing different sources (only 13.7% citation overlap).

This matters because it suggests these aren’t just a “short version” and “long version” of the same answer. They’re two distinct systems that happen to converge on similar conclusions through different paths.

For marketers and SEO professionals, this raises critical questions:

• If your brand is cited in AI Overviews, will it appear in AI Mode too?
• Do you need separate optimization strategies for each?
• What does it mean when two AI systems agree on what to say but not where they found it?

We analyzed citation patterns, content similarity, and entity mentions across hundreds of thousands of queries to find out. Here’s what we discovered.

Key findings

• Citation overlap: Only 13.7% of citations overlap between AI Overviews and AI Mode, indicating they cite different sources in practice.
• Word-level overlap: Very low (16%) word-level overlap between AI Overviews and AI Mode. They start with the same first sentence only 2.51% of the time.
• Semantic similarity: ~9 out of 10 times, AI Mode and AI Overview agreed on what to say; they just said it differently and cited different sources.
• Entity overlap: AI Mode responses include 2.5x more people and brand entities than AI Overviews. If your brand gets mentioned in AI Overviews, there’s a 61% chance it’ll also appear in AI Mode.
• Brand gaps: 32.8% of responses had no person or brand mentioned at all.
• Citation gaps: For 3% of responses, AI Mode doesn’t cite any sources. AI Overviews don’t cite any sources 11% of the time.

Overall similarity snapshot: AI Overviews vs AI Mode response similarity indicating 16% word similarity, 13.7% citation similarity and 86% semantic similarity between the two.

Methodology

We analyzed September 2025 US data from Ahrefs’ Brand Radar, examining 540,000 query pairs for citation and URL analysis, and 730,000 query pairs for content similarity analysis. For each query, we captured both an AI Mode response and an AI Overview response.

We measured citation overlap by identifying how many URLs appeared in both AI Mode and AI Overview responses for the same query. We also tracked domain preferences to see which websites each platform cited most frequently.

For content similarity, we used two metrics:

• Jaccard similarity to measure word-level overlap (unique words in common divided by all unique words)
• Cosine similarity to measure semantic overlap on a scale from 0 (completely different) to 1 (identical meaning)

We also analyzed entity overlap by counting how many people, organizations, and brands were mentioned in both responses.

Sidenote: This analysis compares single generations of AI Mode and AI Overview responses. Our previous research showed that 45% of AI Overview citations change between generations. This means the citation pools available to each system may overlap more than our single-snapshot comparison suggests. However, the low overlap we observed (13.7%) indicates that even when multiple sources could support an answer, AI Mode and AI Overviews often select different ones in practice.

Cited URLs overlapped just 14% of the time

AI Mode and AI Overviews cited the same URLs only 13.7% of the time. When we looked at just the top 3 citations from each, the overlap was slightly higher at 16.3%. This means that 87% of the time, these two systems are pulling from completely different sources to answer the same query.

The domain preferences also differed between the two systems.

The most notable differences

• YouTube held the top position in AI Overviews, being cited more than encyclopedic sources.
• Wikipedia appeared in 10% more AI Mode citations than for AI Overviews.
• While Reddit was cited a similar amount, Quora appeared 3.5x more in AI Mode citations.
• Health websites were cited almost twice as much in AI Mode as in AI Overviews.
• Facebook was also cited twice as much in AI Mode as in AI Overviews.

AI Mode appears to lean more heavily on encyclopedic and detailed medical sources as it builds longer responses, while AI Overviews show a stronger preference for video content and community-driven platforms like Reddit.

However, both systems also showed similar preferences for content types: both overwhelmingly preferred article-format content, while AI Overviews cited videos and core pages nearly twice as often as AI Mode.

Try this yourself

You can see what sources AI Overviews and AI Mode cite the most in Ahrefs’ Brand Radar. Run a blank search and check the Cited domains report.

Filter by AI Overview and AI Mode separately to see their preferred sources.

You can also filter for your target topics or specific brands if you want to analyze a more specific segment of the data.

Why the difference in citation rates?

AI Mode is more reliable for attribution. Only 3% of responses lack citations compared to 11% for AI Overviews.

A few possible reasons:

• Length and format requirements: 4x longer responses need more grounding and supporting evidence.
• User expectations differ: AI Overviews appear in traditional search results where a quick fact may be enough. AI Mode is an interactive chat or research experience where users expect transparency about sources.
• Query filtering: AI Overviews likely surface for more edge cases that don’t warrant citations, while AI Mode may filter these out or handle them differently.

What these findings mean for marketers and SEO professionals

These distinctions between AI Mode and AI Overviews have direct implications for how you approach AI optimization.

• Track visibility separately: With only 13.7% source overlap, being cited in one doesn’t guarantee visibility in the other. Monitor your visibility in both (e.g., via Ahrefs’ Brand Radar).
• Focus on semantic authority, not exact wording: The 86% semantic similarity suggests both systems look for the same themes, expressed differently. Build topical authority and comprehensive coverage rather than targeting exact phrases.
• Account for format differences: AI Mode’s higher citation rate (97%) and entity expansion favor longer, well-sourced content, especially from encyclopedic sources. AI Overviews prefer video and community platforms like Reddit.
• Expect more competition in AI Mode: If you’re cited in an AI Overview, there’s a 61% chance you’ll appear in AI Mode too—alongside additional competitors who didn’t make the shorter cut.
• Invest in encyclopedic content: Wikipedia appears in 28.9% of AI Mode citations versus 18.1% in AI Overviews. Consider how your content can serve as a comprehensive reference or be cited in existing encyclopedic resources.

The bottom line

Treat AI Mode and AI Overviews as separate channels with overlapping goals but different execution. Optimize for both, but don’t assume success in one translates to the other.