How to measure topical authority

Topical Authority is still a mystical concept, partly because we don't have a good way to measure it. In this post, I want to offer a method to quantify Topic Authority.

How to measure topical authority

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Topical Authority seems to be the latest rage in SEO.

To start, here is a selection of definitions from different sites:

Topical Authority is a way of balancing the PageRank for finding more authoritative sources with the information on the sources.
Topical authority can be described as “depth of expertise.” It’s achieved by consistently writing original high-quality, comprehensive content that covers the topic.
Topical authority is a perceived authority over a niche or broad idea set, as opposed to authority over a singular idea or term.
Topical authority is one of the ways Google measures “quality” as a ranking factor—along with page authority and domain authority.

In other words, there is little agreement on the same definition, and the reason is that we don’t have a common way to measure Topical Authority. Only when we’re able to measure something are we able to understand the inputs and outputs.

I critiqued topical authority as a “ghost concept” in my previous article because the argumentation behind it is often so vague. “We’re not ranking well because our Topical Authority is low” is a sentence I hear more and more, but what does that mean? When do you know your Topical Authority is low vs. high beside a personal opinion?

I want to provide an idea for measuring Topical Authority in the hope that it moves us forward as SEO community and that we can replace opinions with good ‘ol data.

The logic behind Topical Authority

I read a lot of articles about Topical Authority. This is how they make sense of the idea:

1/ Google rewards sites that cover a topic in-depth

2/ It does so by comparing how well the site covers relevant entities with Google’s own understanding of entity relationships

3/ Google also takes the site’s backlink profile and mentions on the web into account

Keep in mind that the SEO community came up with the term Topical Authority and It is not a concept Google invented or uses to our knowledge. I also want to point out that most case studies about Topical Authority are very vague. I haven’t yet seen convincing evidence behind the recommendations for improving Topical Authority, but I think the missing piece here is not having a good measure for it.

How to measure Topical Authority

Even though 15% of daily Google searches are new, websites cannot get more traffic than there are searches. That means the traffic from keywords within a topic is also limited by the number of searches. Based on the logic I outlined above, the most authoritative site for a topic gets the highest share of traffic from the keywords within it.

The easiest way to measure Topical Authority then is the share of traffic a site gets from a topic. I call this Topic Share, similar to market share. The logic is that the more traffic a site gets from the keywords in a topic, the more authoritative it is for that topic.

This is a very practical approach because it factors in:

  1. Rank, driven by backlinks, content depth/quality, and user experience
  2. Search volume and how competitive a keyword is
  3. The fact that URLs can rank for many keywords
  4. SERP Features and snippet optimization

To calculate Topic Share, you basically calculate how much traffic you or your competitors get from keywords within a topic.

For example, you can do this in Ahrefs:

  1. Take an entity (head term) like “ecommerce” and enter it in Keyword Explorer
  2. Go to Matching Terms and filter for Volume = > 10
  3. Export all keywords and upload them again in Keyword Explorer
  4. Go to traffic share by domains
  5. Traffic Share = Topic Share = “Topical Authority”

The easiest way to find an entity is by looking at whether Google shows a Knowledge Panel for it in the search results or not.

Example: “ecommerce”

Ahrefs shows 29,135 keywords that contain the term “ecommerce” and have at least a search volume of 10 (minimum) in the Keyword Explorer. In theory, those 29K keywords reflect 100% Topic Share. If a domain ranked #1 for all of them, it would have the highest Topic Share. If it would magically rank on all top positions, it would have 100% Topic Share, which is practically impossible.

For “ecommerce”, I calculated Topic Share based on the top 3K keywords by search volume. Shopify is leading with 11% Topic Share, closely followed by Bigcommerce with 10% and Nerdwallet with 3%.

Example: “spend analysis”

I want to provide another example with a smaller topic. “Spend analysis” has 142 keywords. Following the same process, jaggaer.com has the highest Topic Share with 15%, Sievo 13%, and Tipalti 7%.

To track Topic Share continuously, you could set up a rank tracking project and monitor traffic share for these keywords. However, for large topics, this might not be cost-efficient, and you might want to do this for multiple topics and would quickly get into the 100,000s of keywords to track. The best solution I see is running this analysis once a month and tracking changes manually (not efficient but practical).

Closing thoughts

There is nothing magical about Topic Share. It’s merely an approach to measuring Topical Authority and simplifying the idea of authoritativeness.

Growing Topic Share then is a matter of creating more content, improving existing content, optimizing your snippets and building better links to rank higher, for more keywords and increase click-through rate.