2013 Search Engine Ranking Factors – Data and Conclusions

The 2013 Search Engine Ranking Factors report has been released by Moz. In a field as data-driven as SEO/SEM, it is always worth evaluating large scale data such as this.

In the past, Google has said that it uses over 200 signals in its search algorithm.  (Note:  It is unclear how much this has changed since the recent introduction of Hummingbird.)  The data summarized below can provide a sense of what may be most important to Google by quantifying the characteristics of high ranking sites and pages.

Key data and conclusions from the study:

  1. Page Authority is the most highly correlated metric at .39.
  2. Page-level anchor text correlation with higher rankings remains strong, with most of its metrics from .29 to .23.
  3. On-page keyword usage correlation with higher rankings continues to decline and is significantly lower than that of page-level anchor text.  Various Page Keyword Usage metrics were between .13 and .02.
  4. Page-level link metrics and domain-level link metrics both have high correlations with higher rankings.  In comparison with each other, higher ranked sites are slightly more highly correlated with page-level than domain level link metrics.
  5. Social metric correlations with higher rankings are nearly equal with link metric correlations, and both categories of metrics are among the highest.  However, pages with a lot of shares also generally have a lot of links, so it isn’t entirely clear if both metrics are used in Google’s algorithm, or if they are just naturally correlated with each other.
  6. Google+1 shares and higher rankings have a very high correlation.  Even though Google states that Google+1s aren’t part of their algorithm, it is still worth noting.

Summary of top metrics:

Page Authority: .39
Number of Google +1s: .30
Number of Unique Cblocks Linking to Page: .29
Number of Unique IPs Linking to Page:  .29
Number of Root Domains Linking to Page: .29
Number of Root Domains Linking to Page with Partial Match Anchor Text: .29

This top group is followed closely by various other Page Link Authority Features, Domain Link Authority Features, and Page Level Anchor Test metrics coming in at .28 or .27.

Facebook-specific metrics included: Sum of Facebook Shares, Likes, and Comments at .27, and Number of Facebook Shares also at .27.

For more information on how to interpret and apply this comprehensive new data, please contact us.