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John Mueller Rebuts Idea that Google Uses Domain Authority Signal

Google's John Mueller reaffirms that Google does not have a domain authority metric or signal in use at Google.

There has long been a debate as to whether a site or domain can contain authority. Some people feel that Google has a metric that allows a site to rank pages more easily than other sites. While others feel a site authority metric creates a bias favoring older sites. Who is right? John Mueller provides an answer.

Search marketing expert Bill Hartzer asked a question on the recent Reddit AMA with John Mueller about a domain authority ranking signal. John Mueller’s response deflected a straight answer but also was consistent with all previous responses from Googlers that a domain authority ranking signal is not in use at Google.

John Mueller rebutted the idea that Google uses a domain authority signal with a tongue in cheek response.

Difference Between Domain Authority and Domain Authority

There is an idea in SEO that sites that accumulate age and links also accumulate what’s called Authority. This is interchangeably known as Site Authority and Domain Authority, although some may quibble that Domain Authority is more tightly associated with domain names.

Nevertheless, both terms are used interchangeably. The concept of domain authority has been around since at least 1999, with the publication of a paper by Jon Kleinberg called, Authoritative Sources in a Hyperlinked Environment.

It is this concept of domain authority that is behind the choice of the phrase Domain Authority for Moz’s metric that is also called, Domain Authority. Moz’s metric is their own secret calculation based on their idea of what ranking signals are needed to rank in Google. Moz’s Domain Authority is strictly their own editorial decision based on their understanding of ranking signals and is not what is under discussion here.

History of Site/Domain Authority

15 years ago the overall PageRank score of a site could cause a bias in Google search results that favored sites with a large amount of PageRank. It was not unusual to see the same site rank for phrases such as Web Design San Francisco as well as Web Design Nashville, based solely on the high PageRank score of the main page of the website.

There is a history to the idea and it starts with a famous algorithm called HITS. The HITS algorithm divided the Internet link structure (aka link graph) into hubs and authorities. Hubs were good sites that linked out to good sites. Authority sites were sites that received the most links from hubs. An analogy would be if you were shopping for a car and several friends recommended the dealership down the road from the local malls. The friends making the recommendations would be the hubs and the dealerships would be the authority sites. Here is the research paper from 1999.  The HITS algorithm featuring the concept of site authority was state of the art… for 1999.

PageRank came afterward and it was noticed that sites with high PageRank tended to rank better. Google’s algorithm was biased toward sites with high PageRank. That’s why in this sample SEO Proposal published in 2003 one of the goals of the SEO project was to increase PageRank:

Link popularity building campaign

To achieve high PageRank (link popularity)
…high-quality sites receive a higher PageRank, which Google remembers each time it conducts a search.

That is the root of the idea of Domain Authority. It started with Jon Kleinberg’s Hubs and Authorities algorithm in 1999 and the idea was further reinforced by Google’s PageRank. Site authority/domain authority was a valid idea based on observations in Google’s search results. The idea of domain authority was created for a time before statistical analysis and before large scale CTR testing was introduced.

Observations based on Google’s search results pages in the early 2000’s are one of the origins of the concept of Site Authority/Domain Authority. The other source is the Kleinberg Hubs & Authority algo which predates PageRank.

Evidence of Site Authority

A hypothesis is an explanation for something you can observe. Examples of hypotheses are that the sun revolves around the earth and that the earth is flat.

A theory is an idea that has been tested, that has substantiating evidence. An example of a theory are explanations based on official statements from Google, research papers you can read, patents that you can read.

No SEO will ever point to a Google patent or research paper to justify the idea that a Site/Domain Authority exists. Wikipedia has published a page about Domain Authority  and the footnote links do not cite a single research paper or patent by Google. Not one.  According to the footnotes, Wikipedia’s information is largely based on blog posts by SEOs. There are no links to anything official from Google.

The fact that no such official confirmation or evidence exists logically presents a high likelihood that the domain authority ranking signal does not exist. That fact pushes the concept of Site Authority into the classification of Hypothesis.

But let’s set that aside for now and review the evidence for the hypothesis of site authority and why the belief persists.

New Pages on Old Sites Perform Better

The classic hypothesis for site authority is based on the observation that new content on an existing domain performs better than the same content on a new domain.

Is that evidence that an old site has more authority? Or is it evidence that a new site is trying to rank for keywords that are beyond its natural ability? A brand new site can rank for phrases. Under competitive circumstances, no site, whether new or old, has a high likelihood for ranking a new web page. The more competitive a keyword phrase is the more difficult it is to rank.

So it follows that a new sites inability to rank is tied more to the fact that it is missing the signals neccessary for ranking in competitive spaces. Those signals can be social media mentions, links, brand name mentions, comprehensive nature of the content itself, ratings, user generated content on the site that indicates site visitors are engaging with the site and so on.

Those are a lot of signals that help a site rank better. taken together they can signal that a site has authority. But they are not a site authority metric. They are a vast amount of signals common to Google’s Core Ranking Algorithm.

True definition of site authority

The True Definition of Site Authority?

Some SEOs say they use the phrase Site Authority to loosely refer to those signals that indicate that a site has a high quality. That’s a useful way to describe what Site Authority really is.

I discussed the concept of site authority with search marketer Steven Kang, administrator of the popular SEO Signals Lab Facebook Group and he explained his reason for using the phrase Site Authority:

“I am just labeling that unknown multiplier effect as a trust factor, that’s all.”

That’s a realistic definition of Site Authority, as a catch-all for all the quality signals that Google uses in it’s core algorithm. It’s not asserting that Site Authority is an actual signal or metric in itself that is in use at Google. It is simply shorthand for all the signals that are in use by Google.

What Makes a Page Relevant?

The reality is that high PageRank sites no longer dominate the SERPs. That makes it difficult to insist that a metric like Site Authority or Domain Authority is influencing ranks. This is something you can confirm with your own eyes. The sites with the most links no longer win the top of the ranks.

It is well established that Google is looking at CTR and Viewport metrics to identify what kinds of sites satisfy users the most. User sastisfaction is the ultimate decider of what site gets to rank number one not which site has the most links or which site is the most spam free or any combination of those kinds of metrics.

Why a Site Authority Signal Would Not Work

A web page doesn’t need to have a high PageRank, Site Authority or Domain Authority in order to rank well. A page needs to be relatively spam free and generally have qualities that define a good user experience. Inbound links help build credibility that a page is useful. That’s enough to be considered for ranking.

Now, if you dial up the influence of things like site age, domain TLD (.edu, .gov, .com), inbound links, sites with links from .gov or .edu sites, take your pick, what would happen is that little sites would start to lose their positions.

That would be an unfair bias toward small sites that may contain the best answer to a search query. What counts today is the relevance to a user, not how many links a page or a site has.

The ultimate evidence that Google does not use any form of Site Authority or Domain Authority metric is found in the huge body of publicly filed patents and research. There is absolutely no evidence that Google has created and used any kind of Domain Authority metric. If they did, I who collect and read research papers and those like Bill Slawski who write about patents would be talking about it. But the literature is not there.

That and the fact that Googlers have repeatedly stated that no such metrics exist at Google should be enough to kill the idea. But for some reason the idea of Site Authority still exists. Why?

Facts About Domain Authority

Google has come a long way since 2003. The concept of Domain/Site Authority should be set aside because it is no longer valid. To some SEOs the idea of domain authority seems almost eternal and unchangeable, like the right to free speech and guns. Out of their cold dead hands. But let’s tally up the facts:

  • Googlers have consistently stated that Google does not use any Domain Authority metric
  • Google have never researched or patented a domain authority metric
  • The concept of site authority is nearly 20 years old and irrelevant. The algorithms based on that were discarded, depreciated or updated.

An honest and objective review of the concept of site authority has only one conclusion: Site/Domain authority does not exist as a metric that is in use at Google.

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Category SEO
SEJ STAFF Roger Montti Owner - at

I have 25 years hands-on experience in SEO and have kept on  top of the evolution of search every step ...

John Mueller Rebuts Idea that Google Uses Domain Authority Signal

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