Google’s founders Larry Page and Sergey Brin wrote a university paper called The Pagerank Citation Ranking: Bringing Order to the Web.
This is the origin of what we commonly call “authority”. Now let’s put this in a real life example. You are about to undertake surgery and you have two surgeons in front of you, the first has watched a few Tiktok videos and how-to perform surgery videos on Youtube, the other was referred to you by your trusted doctor, worked their way through medical school, and written papers on the very same surgery they are about to perform on you.
Of the two, its pretty obvious who you would chose for your surgery!
Search engines have the same challenge, lets take travel as another example. There are thousands of travel sites out there, how does a search engine know which site to rank first, second, third etc?
In simple terms, Relevancy is one part, Authority is the other.
Search engines crawl and index websites and store the pages and the links between paged in their index (database).
From having a copy of the websites they crawl in their database, their able to analyse the links between websites and see who is linking to who.
A link pointing to your website from another website is seen as a “vote”. The more votes you have, the more likely you are to perform well in Search Engines.
However not all links are equal. If we were to get a link from a reputable site like the searchenginejournal.com that would carry more weight/value than a link from a random directory.
Back when we started practising SEO the term used was “Pagerank” this has now evolved and the industry uses “Authority”.
Authority is represented as a number, usually on a scale of 0 to 100, with 100 being the highest.
Authority scores are exponential, so as you get higher, it increasingly becomes more and more difficult.
There are SEO tools like Ahrefs, Moz, SemRush and Majestic which all offer their own “flavour” of the authority metric.
Our favourite is Ahrefs, it’s expensive, but its our go-to tool and we use it everyday. You can use Ahrefs to check your websites authority (as measured by Ahrefs) by using their free Website Authority Checker.