Google has no single authority metric but rather uses a bucket of signals to determine authority on a page-by-page basis.
Google’s fight against problematic content has drawn renewed attention to a common question: how does Google know what’s authoritative?
The simple answer is that it has no single “authority” metric. Rather, Google looks at a variety of undisclosed metrics which may even vary from query to query.
When Google first began, it did have a single authority figure. That was called PageRank, which was all about looking at links to pages. Google counted how many links a page received to help derive a PageRank score for that page.
Google didn’t just reward pages with a lot of links, however. It also tried to calculate how important those links were.
A page with a few links from other “important” pages could gain more authority than a page with many links from relatively unremarkable pages.
Even pages with a lot of authority — a lot of PageRank — weren’t guaranteed to rocket to the top of Google’s search results. However PageRank was only one part of Google’s overall ranking algorithm.
The actual words within links had a huge impact. The words on the web pages themselves were taken into account. Other factors also played a role.
These days, links and content are still among the most important ranking signals. However, Αrtificial Ιntelligence — Google’s RankBrain system — is another major factor. In addition, Google’s ranking system involves over 200 major signals.
Even our Periodic Table of SEO Success Factors that tries to simplify the system involves nearly 40 major areas of consideration. None of these signals or metrics today involve a single “authority” factor as in the old days of PageRank.
Google uses a bucket of “signals” that increase and make more visible the result of a pages’ validity.
While there’s no single authority figure, that bucket of signals effectively works like one. #Google says authority is done on a per-page basis. In particular, it avoids the idea of domain authority because that can potentially lead to false assumptions about individual pages, especially those on popular sites.
For instance, sites like YouTube or Tumblr are using their popularity for individual pages within the sites and give those pages a reward they don’t necessarily deserve. In these cases, it is advisable to ask ourselves about the validity of the user and not the validity of the site.
How fast a site is or whether a site has been impacted by malware are two things that can have an impact on pages within those sites.
When all things are equal with two different pages, sitewide signals can help individual pages. Consider two articles on the same topic, one on the Wall Street Journal and another on some fly-by-night domain. Given absolutely no other information, given the information we have now, the Wall Street Journal article looks better. That would be us propagating information from the domain to the page level.
But pages are rarely in “all things equal” situations. Content published to the web quickly acquires its own unique page-specific signals that generally outweigh domain-specific ones. Among those signals are those in the bucket used to assess page-specific authority.