Site authority (siteAuthority)

What is siteAuthority?

siteAuthority is an attribute in the leaked Google Content Warehouse API documentation. In the CompressedQualitySignals module it is described as "converted from quality_nsr.SiteAuthority, applied in Qstar". Qstar is the quality score described in trial exhibits as Q*.

Mike King of iPullRank was among the first to highlight it, in an analysis dated May 27, 2024.

In reality, as part of the Compressed Quality Signals that are stored on a per document basis, Google has a feature they compute called 'siteAuthority.'

Mike King, Secrets from the Algorithm: Google Search's Internal Engineering Documentation Has Leaked, iPullRank

What has Google said about domain authority?

Googlers have repeatedly said Google does not use an overall domain authority score. Search Engine Roundtable reported one of the most quoted examples, a tweet from Gary Illyes, on October 28, 2016.

Read closely, the statements and the leak are not a direct contradiction. The denials were usually aimed at third-party metrics such as Moz's Domain Authority, which are link-based estimates. siteAuthority is documented as a converted quality signal feeding Qstar. What the leak does undermine is the looser message that Google has no site-level measure of standing at all.

we don't really have 'overall domain authority'. A text link with anchor text is better though

Gary Illyes, Google, Google's Gary Illyes: We Don't Have Overall Domain Authority In Our Rankings, Search Engine Roundtable

What evidence is there that Google uses site authority?

The evidence label is leak evidence. The attribute name and its one-line description are real documentation, and Google did not dispute the leak's authenticity, but the documentation does not show weights, how siteAuthority is computed, or whether it was in use at the time of the leak.

Separately, Google's own ranking systems guide confirms that site-wide signals exist, and DOJ exhibit PXR0356 describes Q as largely related to the site rather than the query. Those support the idea of a site-level quality input without confirming the siteAuthority attribute specifically.

We would caution against making inaccurate assumptions about Search based on out-of-context, outdated, or incomplete information.

Google spokesperson, Google responds to leak: Documentation lacks context, Search Engine Land

What about hostAge and the Google sandbox?

The sandbox debate is about whether new sites are held back. The leaked PerDocData module includes a hostAge attribute, described as the earliest firstseen date of all pages on a host, with data "used in twiddler to sandbox fresh spam in serving time".

That wording supports a narrow claim: new hosts can be filtered when they look like spam. It does not show a blanket delay for every new site. SparkToro and iPullRank both presented it as contradicting earlier Google denials of a sandbox.

What does site authority mean for my site?

Build standing on one host. Content published on a fresh subdomain, microsite or newly registered domain starts without the site-level signals the main host has accumulated, and new hosts are the ones the hostAge description associates with spam filtering.

A falsifiable test: when you launch a new section, compare time to first impressions for URLs placed in a subfolder of the established host against a comparable set on a new subdomain. If site-level signals matter as the leak suggests, the subfolder set should gain impressions faster.

Site-wide signals and classifiers are also used and contribute to our understanding of pages.

Google, A guide to Google Search ranking systems, Google Search Central

Which Laurelin audit checks test for site authority?

The new check, content split across new subdomains or microsites instead of the established host, flags where a site is dividing its standing. It is a proxy: siteAuthority cannot be read from outside Google.

Related existing checks:

• Low referring domain authority vs competitors: third-party link metrics are the nearest observable proxy, with the caveats above.
• Expired domain parasite abuse: the abuse pattern that trades on inherited site-level standing.
• Unintended cross-domain canonical: sends signals to another host by mistake.
• Redirect to an irrelevant page: migrations that fail to carry signals to equivalent URLs.
• Thin content: weak pages dilute a site-level quality signal.

What are the key dates for Google site authority?

• 2016-10-28: Search Engine Roundtable reports Gary Illyes saying Google does not really have overall domain authority (source)
• 2024-05-27: iPullRank analysis highlights the siteAuthority attribute in leaked documentation (source)
• 2024-05-29: Google comments on the leak, cautioning against out-of-context assumptions (source)