We Analyzed 11.8 Million Google Search Results. Here’s What We Learned About SEO

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We recently analyzed 11.8 million Google search results to answer the question:

Which factors correlate with first-page search engine rankings?

We looked at content. We looked at backlinks. We even looked at page speed.

With the help of our data partner Ahrefs, we uncovered some interesting findings. And today I’m going to share what we found with you.

Here is a Summary of Our Key Findings:

  1. Our data shows that a site’s overall link authority (as measured by Ahrefs Domain Rating) strongly correlates with higher rankings.
  2. Pages with lots of backlinks rank above pages that don’t have as many backlinks. In fact, the #1 result in Google has an average of 3.8x more backlinks than positions #2-#10.
  3. Comprehensive content with a high “Content Grade” (via Clearscope), significantly outperformed content that didn’t cover a topic in-depth.
  4. We found no correlation between page loading speed (as measured by Alexa) and first page Google rankings.
  5. Getting backlinks from multiple different sites appears to be important for SEO. We found the number of domains linking to a page had a correlation with rankings.
  6. The vast majority of title tags in Google exactly or partially match the keyword that they rank for. However, we found essentially zero correlation between using a keyword in your title tag and higher rankings on the first page.
  7. Page authority (as measured by Ahrefs URL Rating) weakly correlates with rankings.
  8. We discovered that word count was evenly distributed among the top 10 results. The average Google first page result contains 1,447 words.
  9. HTML page size does not have any correlation with rankings. In other words, heavy pages have the same chance to rank as light pages.
  10. We found a very slight correlation between URL length and rankings. Specifically, short URLs tend to have a slight ranking advantage over longer URLs.
  11. Our data shows that use of Schema markup does not correlate with higher rankings.
  12. Websites with above-average “time on site” tend to rank higher in Google. Specifically, increasing time on site by 3 seconds correlates to ranking a single position higher in the search results.

Authoritative Domains Tend to Rank Higher in Google’s Search Results

We found that a website’s overall link authority (measured using Ahrefs Domain Rating) correlates to higher first page Google rankings:

In general, average Domain Rating increases by SERP position.

In fact, a website’s overall authority had a stronger correlation to rankings than the authority of the page itself (URL Rating).

Key Takeaway: Higher Domain Ratings correlate with higher rankings on Google’s first page. Therefore, domains have a significant advantage in the SERPs.

Pages With More Backlinks Tend to Rank Higher Than Pages With Fewer Backlinks

One of the most interesting findings from this analysis was that very few pages have any backlinks.

In fact, we found that approximately 95% of all pages have zero backlinks.

This finding is in-line with this Backlinko-BuzzSumo analysis of 912 million blog posts, which found that 94% of all content has zero backlinks.

In fact, so few pages had any backlinks that “zero backlink” pages were beginning to skew the data. So for this ranking factor we decided to run this particular analysis excluding pages with zero backlinks.

Perhaps not surprisingly, we discovered that pages with the highest number of total backlinks tended to rank best in Google.

We also found that the #1 results has an average of 3.8x more backlinks than the results rankings #2-#10.

Key Takeaway: Even though Google continues to add diversity to its algorithm, it appears that backlinks remain a critical ranking signal.

Comprehensive Content Strongly Correlates With Higher Rankings

Many SEO experts claim that comprehensive content performs best in Google.

Put another way: content that covers an entire topic on a single page may have a direct or indirect relationship with rankings.

We decided to put this assumption to the test. Specifically, we ran a subset of our full 11.8M URL dataset through the content analysis tool Clearscope.io.

Our analysis found a clear correlation between “Content Grade” and Google rankings in both desktop and mobile results.

In fact, when looking at the top 30 results, increasing Content Grade by 1 approximates to increasing rankings by one position. Which suggests a significant relationship.

Key Takeaway: Writing comprehensive, in-depth content can help pages rank higher in Google.

Page Loading Speed Does Not Have a Correlation With Rankings

Google has used site speed as an official ranking signal since 2010.

However, we wanted to know:

Does site speed correlate with actual Google rankings?

Overall, we found zero correlation between site speed and Google rankings:

Key Takeaway: The average Google first page result loads in 1.65 seconds. However, we found no correlation between site speed and Google rankings.

The Number of Referring Domains Appears to Have an Influence on Rankings

Many SEO experts agree that getting multiple backlinks from the same domain has diminishing returns.

According to our analysis, this appears to be the case. We found that domain diversity has a substantial impact on rankings.

Key Takeaway: Getting links from a diverse group of domains appears to be important for SEO.

Most Title Tags on Google’s First Page Contain Keywords That Are an Exact or Partial Match of That Search

Since the early days of search engines, the title tag has been considered the most important on-page SEO element.

Key Takeaway: Pages in Google’s top 10 results contain 65% to 85% of the keywords that they’re ranking for in their title tag. However, we found very little (if any) correlation between keyword-optimized title tags and higher rankings on the first page.

Keyword-Optimized H1 Tags Don’t Correlate With Higher First Page Rankings

Key Takeaway: Like with title tag optimization, H1s may be a “ticket to entry” factor that can help you crack Google’s first page. However, keyword-rich H1s may not be strong enough of a ranking signal to help a page move up the first page results.

Webpage Authority (URL Rating) Has a Slight Correlation With Higher Rankings

Key Takeaway: The link authority of each individual page on your site appears to have a relatively small impact on rankings compared to your site’s overall domain authority.

The Mean Word Count of a Google First Page Result Is 1,447 Words

Key Takeaway: Pages with higher word count appear to have the same chance of ranking highly on the first page compared to pages with a lower word count. The mean word count of a Google first page result is 1,447 words.

Page HTML Size Has No Relationship With Rankings

Key Takeaway: Page size doesn’t appear to have an impact on Google rankings.

Short URLs Tend to Rank Slightly Better than Long URLs

Key Takeaway: Shorter URLs have a correlation with higher rankings. The average URL on Google’s first page is 66 characters long.

There is No Correlation Between Schema Markup and Rankings

Key Takeaway: Using Schema markup may have its place. But it doesn’t directly correlate with higher Google rankings.

Websites With Above-Average “Time On Site” Tend to Rank Higher In Google

Key Takeaway: The average time on site for a Google first page result is 2.5 minutes.