
Key takeaways
- Zyppy analyzed 23 million internal links across 1,800 websites and roughly 520,000 URLs, cross-referenced against Google Search Console click data.
- Pages with 0 to 4 internal links averaged about a quarter of the Google Search clicks of pages with 40 to 44 internal links in Zyppy's dataset.
- Traffic gains reversed past roughly 45 to 50 internal links, and Zyppy states plainly that its findings are correlational, not proof of causation.
- Google's own documentation says every page you care about should have a link from at least one other page on your site.
- Google states that a submitted sitemap is merely a hint and does not guarantee a page will be crawled, so links remain the primary discovery path.
A single-site before-and-after case study can show what happened on one domain. What it cannot show is whether the pattern holds anywhere else. For that, the closest thing the industry has is Cyrus Shepard’s Zyppy study, which measured 23 million internal links across 1,800 sites and lined the results up against real Google Search Console clicks.
Zyppy’s real numbers
Zyppy pulled internal-link data from roughly 520,000 URLs across 1,800 websites, a total of 23 million internal links, then joined that dataset to each URL’s actual Google Search Console click count. The headline pattern: URLs with 0 to 4 internal links pointing at them averaged about 2 clicks from Google Search, while URLs with 40 to 44 internal links averaged roughly 4 times that many. Past about 45 to 50 internal links, the relationship reverses and clicks start declining again as link count keeps climbing, a pattern Zyppy attributes partly to over-linked pages diluting the value of any one link and partly to bulk sitewide navigation links counting differently than unique, in-content links.
On that second point, Zyppy is explicit that a link appearing in a sitewide footer or navigation menu may still pass a meaningful amount of PageRank, but functions as a single relationship with one anchor text, however many pages it appears on, unlike a one-off contextual link placed inside an article. Zyppy also states directly that this is mostly a correlation study, not a controlled experiment, and cautions readers against treating any of its conclusions as more certain than the data supports.
Google’s documented discovery mechanics
Separately from what Zyppy measured, Google’s own developer documentation explains the mechanic that makes link count matter in the first place. Google’s guide to how search works describes three ways a page enters Google’s index of known URLs: Google has already visited it, Google extracted a link to it from a page it already knows, or a site owner submitted it through a sitemap. Google’s link best-practices page states the underlying expectation plainly: “Every page you care about should have a link from at least one other page on your site.”
A sitemap is not a substitute for that link. Google’s own sitemap documentation says submitting one “is merely a hint: it doesn’t guarantee that Google will download the sitemap or use the sitemap for crawling URLs on the site.” A page with no internal link pointing to it depends entirely on Google finding it through a sitemap it may or may not act on, or through an external backlink, neither of which Google promises to honor.
Why we care
Put the two sources together and the picture is consistent, not identical. Zyppy’s aggregate data shows a real, measurable relationship between how many internal links a page has and how much Google Search traffic it receives, at a scale far beyond any one site’s crawl log. Google’s own documentation explains a plausible mechanism for the low end of that curve: a page a search engine struggles to discover through links is a page that depends on weaker, unreliable fallbacks to be found at all. Neither source claims that adding internal links will move a specific page’s rankings by a specific amount. What both support is a more modest, defensible claim: pages with very few internal links are working against how Google’s crawler actually finds and revisits content, and that is a real, structural risk worth auditing for, not a superstition.
The evidence
- Sample
- 23M internal links, 1,800 sites, ~520K URLs
Hypothesis: Internal link count measurably tracks with how much Google Search traffic a page receives at scale, and Google's own documented crawling mechanics explain why pages with few or no internal links struggle to be discovered and rewarded.
Method: Reviewed Zyppy's large-scale correlation study, which cross-referenced 23 million internal links across 1,800 websites against Google Search Console click data, alongside Google's own developer documentation on how Googlebot discovers URLs and what submitting a sitemap does and does not guarantee.
Findings
- URLs with 0 to 4 internal links averaged about 2 clicks from Google Search, versus roughly 4 times that for URLs with 40 to 44 internal links, in Zyppy's dataset of 23 million links.
- The traffic benefit reversed past about 45 to 50 internal links, with Google Search clicks declining again as link count kept rising.
- Zyppy notes sitewide navigation links may pass a good amount of PageRank but carry only one anchor-text relationship, unlike unique contextual links from content.
- Google's documentation states every page you care about should have a link from at least one other page on the site, and that a submitted sitemap is only a hint, not a crawling guarantee.
Limitations: Zyppy's own write-up calls this mostly a correlation study and warns that correlation is not causation; the sample, while large, is a small slice of the web's total link graph, and the study draws no controlled causal claim about fixing under-linked pages improving rankings by a specific amount. It measures association between link count and clicks, not a before-and-after experiment on any single site.
Sources
- 1.23 Million Internal Links - SEO Case Study - Zyppy, July 12, 2022Primary
- 2.In-Depth Guide to How Google Search Works - Google Search Central
- 3.SEO Link Best Practices for Google - Google Search Central
- 4.Build and Submit a Sitemap - Google Search Central
About the author

Founder
Founder, UpgradIQ, Inc.
Adam Hafez works on technical SEO and search measurement: how pages get crawled, indexed, ranked and now quoted by answer engines. He founded UpgradIQ, which reads Google Search Console and GA4 to tie ranking movement back to the changes that caused it. He publishes what the data supports and states the limits of it.
- Technical SEO
- Search Console and GA4 measurement
- Answer engine optimization
- Structured data
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