Domain Authority Versus PageRank

Authority Analysis

Anyone who’s ever dipped their toe into the digital marketing pool will have come across the terms Domain Authority and PageRank before. They are the way that the quality of a website is determined by Moz and Google respectively. But what do they mean? Are they accurate and what can you do to influence them in order to get your site a better score?

Let’s find out.

Starting with the God of search that is Google, PankRank was first developed by founders Larry Page and Sergey Brin. To put it in its most basic terms, PageRank (otherwise known as PR) looks at links to determine how useful a site is. It assumes that any website that has a lot of links from other sites pointing to it is being essentially given a vote of confidence when it comes to its usefulness.

The scoring system isn’t completely clear and whilst Google released the equation for the algorithm back in the day, it’s highly likely that it’s since changed and there are now more factors that are taken into account.

The original equation looks like this:

PR(A) = (1-d) + d (PR(T1)/C(T1) + … + PR(Tn)/C(Tn))

When it comes to how this is broken down and calculated, it’s pretty complex. A full explanation can be found on the link above but basically, it’s not just down to the volume of incoming links to any one site that counts, but also the quality of that site too. This means that the code (or equation) has to be run time and time again in order for it to arrive at the right answer as it’s likely to be factoring in millions of links if the site is highly popular.

PageRank scores from one to ten and there’s not too many out there that score a perfect ten. There are numerous sites available online on which you can check the PR but many of these are inaccurate. I typed in http://www.google.com to a couple and got back results of 0, 7 and 9, to give you an idea how much they can vary when it comes to PR checkers online.

pankrank checker

Google’s own toolbar, which gives you the PR of a page whenever you land on it is the best bet and is only available IE (which isn’t the most popular of browsers these days).

Is it Important?

PageRank gives you an idea of the quality of a site which is useful when carrying out guest posting activity. If you have a site that contains a PR of 4 or above, then it’s likely that you get a lot of requests for guest posts as these are valuable to pages with a PR of 4 and under.

Whilst PR gives you a good idea of the quality of a site, it’s becoming less relevant now that Google has banned guest posting for SEO. In fact, according to Matt Cutts, PageRank isn’t updated very often and will “start to go away a bit” when it comes to assessing the importance of individual websites.

Domain Authority

Domain authority was created by Moz and uses a number of different metrics to measure how well a page might perform in search, rather than just looking at links. These are:

  • Age
  • Size
  • Popularity

This is a very basic guide to Moz calculations though, it actually uses more than 40 different metrics to arrive at a score out of 100 and since these are predictive, this means that the score often fluctuates and should only be used as a guide.

Moz uses its own metrics – MozTrust, MozRank, Link profile – to make its calculations and you can install MozBar if you want to see how individual sites score as you land on them and even in Google search results.

So if you put in a search for say, pet food, MozBar will not only show you the score in the toolbar to the top of the page when you land on a site, but also in search results as shown in the image below.

moz bar search results

As you can see, Amazon unsurprisingly has a high Domain Authority (DA), whilst the other results are relatively middle of the road (but still pretty good). Note that there is also a PA value attributed. This is because unlike Google PR, Moz gives a score for both the quality of the overall domain and the individual page, Google PR measures pages but not the overall quality of the domain.

DA is calculated using a number of metrics, whilst PR is measured on links and with this in mind, this appears to make the Moz metric the more valuable of the two, especially in light of Matt Cutts’ comments. The age of a domain is also important as the longer a domain has been in use, the more likely it is to be of a higher quality. This isn’t always the case of course, but more often than not a domain that’s been around and owned by the same company for some time will be one of a half decent quality at least.

There are are in fact many more metrics involved when calculating DA and below are just a few:

  • The quality of inbound links – are high quality sites linking to you?
  • Outgoing links are also important – Who are you linking to? What’s their domain authority, their PageRank? Are you linking too much, too little? All this is taken into consideration.
  • Domain registration info. If you own more than one domain, and that domain begins to become spammy, your others will be penalised too. You have to look after them all.
  • PageRank. Yes, Moz uses PageRank as part of its calculation in determining domain authority.
  • Traffic distribution over time. If a site has a consistent and gradually increasing amount of traffic passing through it, then it is deemed to be worthy of a higher authority than one who has a sudden spike in popularity.
  • Traffic metrics. How many pageviews per visitor are generated? How many returning visitors?
  • Site performance – A slow site means that your authority will drop.

Further Metrics

Whilst DA and PR are considered to be the industry leaders, Majestic SEO also has its own way of measuring the quality of a site with its Trust and Citation Flow metrics. Again, these look at links mostly but are frequently updated and useful for visualising how a site’s link profile is performing.

Trust and citation flows

Interestingly, Majestic teamed up with Twitter earlier this year to produce Twitter cards that show live metrics and Trust/Citation flow charts embedded into the cards. Just how often Majestic is updated probably makes it more valuable than PR if you’re looking strictly at link profiles and the site also allows you to study backlink data for your own and other domains.

So which matters more?

It’s safe to say that none of the metrics are an exact science when it comes to measuring the quality of a site or page, but they do give you a very good guide. This is true not just for looking at guest posting activities and gaining more backlinks, but when you’re checking out the quality of a site that you might be getting information from.

For example, when writing this post and searching for further information, I would generally ignore sites with a very low DA and those that come up as N/A on PR. This is especially true of older sites (new sites naturally have a low DA/PR) as it’s likely that any content on the site won’t be of much use if it’s been there a long time.

When looking at potential client sites too, it’s useful to see at a glance what score the sites have been given to help you come up with an effective strategy when it comes to gaining better search visibility.

All-in-all, Moz is probably the best metric, with Majestic also not far behind when it comes to studying link profiles. However, PR is a Google product so despite its lack of updates is not worth discounting completely until Matt Cutts announces its inevitable demise.

Is Link Profiling Still Worth it?

There’s been a lot of tightening of the rules when it comes to link activity by SEO professionals but good link profile remains vital to a good campaign. Whilst I’ve said for some time that I believe it’s become more necessary to look at SEO and digital marketing holistically, links remain highly important to how search engines measure the value of your site.

With this in mind, perhaps it’s time to get thinking up some great new strategies for attracting new, high quality links and delve further into Moz and Majestic to help you to do this. Whilst great content tends to attract good links, so do infographics, YouTube videos, social media and more, so mix it up a bit and do try to forget about guest posting unless you’re prepared to gather a lot of nofollow links and few dofollow.

17 SEO Myths
Kerry Butters

A prolific technology writer, Kerry was an authority in her field and produced content for a variety of high profile sites in her niche. Also a published author, she adored the written word and all things tech and internet related. Sadly she passed away in February 2016 after a valiant battle with cancer.

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