Do Backlinks Still Matter in AI Search? Insights from 1,000 Domains [Study]

For years, backlinks person been 1 of the strongest signals driving rankings successful accepted search.

But person the rules changed arsenic we participate the caller era of AI search?

Together pinch Kevin Indig, we've tally a information study to analyse really backlinks power visibility successful AI-generated answers.

Let’s dive in.

Key Takeaways

TL;DR: Backlinks are important for AI visibility, but value and authority matter acold much than quantity.

• High-quality backlinks matter much than sheer volume. Domains pinch stronger backlink authority—measured by Semrush’s Authority Score—are mentioned much often successful AI-generated answers. That said, large visibility gains only look erstwhile a tract reaches the higher authority tiers.

• Nofollow links person astir the aforesaid effect arsenic travel links. The study recovered akin relationship values for some types, pinch awesome gains appearing only successful the apical tiers of authority.

• Image-based backlinks tin beryllium conscionable arsenic powerful arsenic matter links. Once a tract already has immoderate authority, image links show moreover stronger correlations pinch AI mentions than matter links—especially for higher-authority domains.

Methodology

We conducted this study successful collaboration with Kevin Indig and Growth Memo.

First, we looked astatine 1,000 randomly selected domains wrong Semrush’s AI Visibility Toolkit to understand really backlink-related signals power visibility successful AI-generated answers.

To that end, we tracked really often each domain was mentioned crossed five starring AI platforms:

• ChatGPT
• ChatGPT pinch Search
• Gemini
• Google’s AI Overviews
• Perplexity

We past compared the number of AI mentions (how galore times a domain was referenced crossed AI-generated answers) and AI Share of Voice (a domain’s visibility successful AI-generated answers comparative to non-branded queries) against key backlink signals:

• Total number of backlinks
• Number of unsocial referring domains
• Ratio of travel vs. nofollow links
• Text links vs. image links
• Authority Score—Semrush’s composite metric that reflects backlink quality, referring domain diversity, integrated postulation to linking pages, and spam signals

Finally, we ran Pearson and Spearman relationship analyses connected the aforesaid dataset to analyse really powerfully each backlink awesome was associated pinch AI visibility—and to place whether those relationships were linear aliases showed period effects.

Learn much astir really we measured the correlations.

Here’s what we found.

1. Authority Boosts AI Visibility, But Only Beyond a Threshold

Domains pinch higher Authority Scores—a metric heavy influenced by backlink value and referring domain diversity—are much apt to look successful AI-generated answers.

However, the effect is mean wide and only becomes important erstwhile a domain crosses into higher authority tiers.

When we compared Authority Score to AI Share of Voice (that is, a brand’s visibility successful AI-generated answers comparative to non-branded queries), the results showed the following:

• Pearson: ~0.23 → a humble linear relationship
• Spearman: ~0.36 → a stronger, threshold-based signal

The spread betwixt these 2 correlations reveals that backlink authority has a moderate wide influence connected AI visibility, but existent gains look only aft reaching definite authority levels. 

In different words, incremental backlink improvements won’t move the needle overmuch until a tract reaches stronger wide authority.

“The large takeaway present is that your backlink needs to deed a minimum threshold. In elemental terms: Don’t expect returns erstwhile you conscionable get started aliases from linear growth. You request a minimum finance to spot the expected impact.”

Kevin Indig, Growth Advisor 

What This Means for You:

• Focus connected breaking authority plateaus. Small nexus wins won’t make a visible difference. To move up, attraction connected earning backlinks from higher-authority, topically applicable sites, specified arsenic well-known publications, starring blogs, aliases manufacture directories. 

• Expand your excavation of referring domains. Getting links from a assortment of different websites matters much than the sheer measurement of links. Prioritize outreach to caller domains successful your abstraction alternatively than collecting much links from the aforesaid sources. 

• Balance authority pinch credibility. Backlinks help, but AI models besides favour brands seen arsenic trustworthy and credible. Keep contented accurate, current, and well-sourced, and purpose for mentions from reputable sites—even without links—to reenforce your authority.

2. Link Quality Drives AI Visibility More Than Volume

The value of backlinks plays a awesome domiciled successful really often a domain appears successful AI-generated answers.

When we compared Authority Score (Semrush’s proxy for nexus quality) pinch the number of AI mentions, the results showed a beardown affirmative relationship:

• Pearson: 0.65 → beardown linear correlation
• Spearman: 0.57 → beardown but somewhat non-linear correlation

This intends domains pinch high-quality backlink profiles look acold much often successful AI-generated answers, particularly erstwhile they transverse cardinal authority thresholds.

Interestingly, the effect varies crossed models: ChatGPT Search and Perplexity measurement nexus value the least, while regular ChatGPT (without Search on) shows the strongest correlation.

What This Means for You

• Prioritize nexus value complete volume. A fewer backlinks from authoritative, applicable websites will thrust acold much AI visibility than dozens of anemic aliases unrelated ones.
• Audit your backlink floor plan regularly. Use devices for illustration Semrush’s Backlink Analytics to pinpoint which domains are adding existent authority, arsenic opposed to low-value aliases spammy ones that could clasp you back.

• Pursue meaningful authority gains. Instead of chasing mini nexus exchanges aliases low-value mentions, target opportunities that genuinely boost credibility, specified arsenic integer PR, master impermanent articles, aliases inclusion successful trusted manufacture resources.

3. Nofollow Links Carry Almost arsenic Much Weight arsenic Follow Links

Nofollow links person astir the aforesaid effect connected AI visibility arsenic modular travel links.

When we compared some (individually) to AI mentions, the correlations were almost identical.

Follow links:

• Pearson: 0.334 → mean linear signal
• Spearman: 0.504 → beardown period signal

Nofollow links:

• Pearson: 0.340 → mean linear signal
• Spearman: 0.509 → beardown period signal

This shows that AI models dainty some nexus types likewise erstwhile evaluating authority and visibility.

The weighting besides varies somewhat by platform: we recovered that Gemini and ChatGPT thin to favour nofollow links a spot more, while Google AI Overviews and Perplexity thin much toward travel links.

What This Means for You:

• Don’t place nofollow links. They lend meaningfully to AI visibility, particularly erstwhile they travel from high-authority sites. Remember: Getting mentioned by an charismatic and applicable root is much important than chasing speedy gains.
• Watch for level nuances and diversify your strategy. Platforms for illustration Gemini and ChatGPT whitethorn reward beardown nofollow links (e.g., from Reddit, Quora, aliases Wikipedia), while Google AI Overviews and Perplexity still thin somewhat toward travel links.
• Keep your links—including nofollow ones—fresh and relevant. Regularly update contented connected pages wherever your marque already has nofollow mentions.

“Just for illustration you update blog posts, update nofollow placements. Rotate successful caller information points, update merchandise screenshots, aliases refresh stats connected contributed articles your marque has earned nofollow links with, truthful links stay applicable and referenced.”

Kevin Indig, Growth Advisor 

4. Image Links Perform arsenic Well arsenic (and Sometimes Better Than) Text Links

Image-based links show a stronger narration pinch AI visibility than matter links.

When we compared the 2 (individually) to AI mentions, the correlations were clear.

Image links:

• Pearson: 0.415 → stronger linear signal
• Spearman: 0.538 → beardown period signal

Text links:

• Pearson: 0.334 → mean linear signal
• Spearman: 0.472 → mean period signal

The advantage of image links besides appears erstwhile a tract has built immoderate authority. 

From mid-level deciles upward, the narration strengthens and peaks astatine the top, while low-authority tiers show small to nary effect.

We besides noticed a fewer differences crossed platforms:

• Perplexity and ChatGPT Search show the strongest nexus betwixt image backlinks and AI visibility
• ChatGPT and Gemini follow pinch somewhat weaker correlations
• Google AI Overviews shows the weakest connection, though it is still noticeable

Overall, image-based backlinks are treated arsenic reliable reference signals crossed ample connection models—delivering the biggest visibility boosts erstwhile a domain reaches higher authority levels.

What This Means for You:

• Invest successful attracting image-based links. Distribute your visuals wherever publishers and creators look for reference material, pinch easy-to-copy embed codes aliases root credits. Share them connected platforms specified arsenic Reddit, LinkedIn, and manufacture newsletters wherever journalists and contented teams root visuals.
• Focus connected adding value. Create useful image assets based connected original research, specified arsenic charts, infographics, merchandise visuals, and information diagrams that others will people embed and nexus to.

“Stop treating images arsenic accessories and commencement treating them arsenic content. The champion ocular contented explains and simplifies captious aliases analyzable topics.”

Kevin Indig, Growth Advisor 

Backlinks Still Matter, But Quality Trumps Quantity successful AI Search

Our study reveals a clear displacement successful really backlinks power visibility: value is king successful the AI era.

Instead of trying to cod arsenic galore links arsenic imaginable and to “hack” the system, you request to attraction connected building value signals and breaking done authority thresholds.

Here’s what you should do:

• Prioritize meaningful authority gains complete incremental nexus building
• Don't disregard nofollow links from high-authority sources
• Invest successful shareable ocular assets that gain image-based links
• Focus connected getting mentioned and cited for contented that genuinely adds value

The bottommost line: AI visibility comes from sustained authority, not one-off nexus wins. Prioritize earning high-quality backlinks that move your tract into stronger authority ranges and support your marque referenced connected credible, up-to-date sources.

How we measured the correlations

To understand really backlinks and AI visibility are connected, we utilized 2 modular statistical measures: Pearson and Spearman correlations.

• Pearson checks for a linear narration betwixt 2 variables. If some values emergence aliases autumn together successful a soft pattern, Pearson picks that up clearly. But if the narration only becomes visible aft hitting a definite constituent (a threshold), Pearson tends to miss it.
• Spearman focuses connected those period effects. It looks astatine whether the values move successful the aforesaid direction, moreover if the curve isn’t perfectly smooth. Spearman is little delicate to outliers and amended astatine spotting situations wherever thing happens for a while. Then the narration abruptly strengthens aft a definite level is crossed.

Both Pearson and Spearman springiness a people betwixt -1 and +1:

• Closer to +1 → beardown affirmative relationship
• Closer to -1 → beardown antagonistic relationship
• Around 0 → small to nary relationship

Looking astatine some helped america uncover whether the narration betwixt various factors is linear aliases threshold-based.