Domain Authority – Definition, Reliability, Accuracy & Topical Relevance

In SEO, domain authority is an arbitrary metric given by some software tools to measure the authority a domain does have in the eyes of search engines.

  • On 6/13/2019 by @lazharichir

A domain authority metric is a hot topic amongst SEO marketers and specialists. While some experts completely ignore such metrics, others swear by them in their overall link building strategy. The main issue of such metrics is they are too broad without considering the topical content of a given domain.

Any domain authority score promises to mirror Google algorithms as closely as possible. Yet, we all know how impossible that is. Therefore, domain authority scores often end up in some funny situations in which a DA of 10 ranks higher than a DA of 65.

While domain scores show a trend or give an idea about the ranking potential of a domain, the data and algorithms they are based on are not Google's. Consequently, the results will inevitably differ from what you will witness in real SERPs. Do not base your entire link building outreach on domain ratings, but use them as one input amongst many others to prioritize amongst many other websites and domains.

What is domain authority in SEO?

In SEO, domain authority is an arbitrary metric given by some software SEO tools to measure the authority a domain does have in the eyes of search engines. Generally, the Domain Authority (or DA) is measured between 0 and 100 with 100 being the desired score. The domain authority SEO metric is also meant to follow a logarithmic growth in which jumping from 0 to 30 is easier than jumping from 60 to 70.

The authority of a domain generally accounts for its backlink profile, both in its quality and quantity. To our knowledge, all domain authority measures to date are proprietary and, therefore, it is impossible to assess the quality of the calculations performed.

How is a domain's authority measured?

Domain authority and domain scores are measured using proprietary algorithms that process a huge amount of data to extract and analyze backlinks. Think of domain authority metrics as follows:

  • A website, or domain, is comprised of pages
  • A page contains links to external domains

By gathering and measuring how many links each page receives, and aggregating the number of backlinks a domain gets, you get a rough idea of how trusted an entire domain is. Obviously, to achieve such results for millions of domains, your software architecture must be able to ingest with petabytes of data. Then, it needs to provide the computing power necessary to run these algorithms at a huge scale.

While the above is a simplified version, there are plenty of signals that may influence the authority of a given domain:

  • Is one page getting all the backlinks for that domain?
  • Are the backlinks spread evenly to the collection of pages?
  • Do the backlinks all come from a single root domain?
  • Have the backlinks all appeared at the same time or over several years?
  • Is the balance of nofollow and dofollow fair?
  • Are there black-hat SEO patterns observed?

These, and dozens more, signals need to be weighed and taken into account when deciding on the final domain authority score shown to the end user. In practice, these algorithms are somewhat inspired by the famous PageRank algorithm, from Google Search.

Look at DA metrics, but don't live and die by them.

What companies have their own domain authority score?

Moz is the most iconic and the original domain authority measurer on the web. They have democratized an easy way of grading a domain by a numbered trustworthiness level. Moz further improved their algorithm in 2019 with the release of Domain Authority 2.0. This update promises to mimic more closely what modern search engines like Google look at when ranking websites and domains.

Ahrefs uses Domain Ratingto provide information on how strong a domain's total backlink profile is. They do so by aggregating and measure the quantity as well as the quality of these backlinks.

SEMRush uses an Authority Score to grade the quality and ranking potential of an entire domain. This tool also offers a trend graph of the score of a given domain. Such graph allows you to visualize the velocity at which a website grew their Authority Score.

While these three SEO tools offer the most used and trusted domain authority metrics, there are dozens of more tools with their own metric name.

Are domain authority metrics reliable and accurate?

A domain authority in SEO is more of an indicator than an accurate metric. Only Google knows how authoritative a website is, and how trusted it will be when ranking it for various search queries.

Additionally, the authority of a domain cannot be given using a single number. In fact, domain authority should be measured for a given topic. Today, these tools will say that is a very authoritative domain, but is it? What if I am search content about aircraft aerodynamics or zoology, aren't there more reliable and trustworthy sources?

A reliable domain authority metric should be scoped to a particular topic or domain, and not merely summarized to an integer.

While domain ratings are too simplistic to be accurate, they do give a rough estimate on how valuable a domain would be if they linked back to your website. Software tools providing authority scores for domains either purchase tons of data, or crawl and analyze it themselves. Their authority metrics are founded in real data and they are trying to make sense of it.

Not being accurate and reliable does not mean it should be ignored. We, ourselves, use some domain authority metrics to prioritize our marketing outreach:

  • Low DA – enqueued in an autopilot cold outreach campaign
  • Mid DA – emailed personally with quick research
  • High DA – thorough research and very hands-on multi-channel outreach

However, when browsing a website ourselves and loving the content, we will completely ignore their domain authority and go with what we see. Whatever a company's software algorithms grade a domain, if as a human you find it great, Google is light years ahead of them so trust your gut. The end goal of a search engine is to understand a piece of content's depth of coverage like we do as humans, not purely based on the article or domain's backlink profile.

While links are still a huge ranking signal, topical authority is advancing fast to take over the pole position. This is why the future of domain authority is topical authority – or, the topical domain authority.

How to create a topical domain authority metric?

Building a perfectly accurate topical domain authority score requires measuring a website's topical relevance by:

  • rating each blog post for the topics it covers
  • weighing backlinks by the source's topical relevance

To have a topical measure of a domain's content, the system must be aware of all topics existing at any time, and score each piece of content against these topics. It would be exceptiionally computationally hungry but indeed, a lot more accurate.

With the progress made in natural language understanding, semantics, and cheaper hardware, such metrics are probably going to come to end-users soon. However, they may be visually less appealing than a red or green-colored number. You may need to deal with a matrix instead.

Backend and frontend developers will work hard to make this valuable domain score easily digestible for their customers. But more importantly, algorithms must focus on a domain's topical backlink profile rather than pure volume.

topical backlinking strategies for cold outreach

Is domain authority a ranking factor?

No, Google does not use any domain authority metric as we know them as a ranking factor. Search engines use their own algorithms to assess the ranking position of web pages.

Domain authority is a metric provided by third-party SEO tools based on their assumptions of what search engines value in a website or domain. While these assumptions make total sense, the weighing and computations are most likely totally different than Google's own data and mathematical formulae.

Can you manipulate domain authority?

Since domain authority is a metric that relies heavily on backlinks for a given domain, it would be possible to manipulate a domain's rating. However, since authority metrics for a given domain are made up by third-party tools and not used by search engines, there would be no gains in manipulating them.

Instead, focus on producing great content that answers the queries of your audience as thoroughly as possible. The only growth you want is an organic one based on clean topical writing and long-term SEO strategies.

How to find my domain authority?

You can find your domain's authority by using domain authority checkers provided by these platforms:

  • SEMRush
  • Moz
  • Ahrefs
  • UberSuggest

Some of them may require you to signup and pay before using the platform. Others have a free area for you to superficially explore data and metrics about a given domain.