Have you ever wondered how search engines determine the authority of a website? If you are involved in SEO or digital marketing at any level, you’ll need to understand the factors that contribute to a website’s ranking in search results. And Domain Authority (DA) is one of the key metrics that webmasters and marketers rely on.
In this guide, we’ll dive deep into the concept of Domain Authority. First, we’ll review the original DA metric from Moz.
Then, we’ll compare the original with competitive metrics offered by leading Search Marketing platforms SEMrush and ahrefs.
By the end of this post, you’ll have a clearer understanding of how these leading formulas differ and which one may be the most suitable for your SEO strategy.
What is Domain Authority?
Domain Authority is a metric that attempts to quantify the strength of a website’s domain in the eyes of search engines.
In the past, we had a metric from Google called PageRank that measure authority for a page on a scale of 1-to-10. They shared these values with us many years ago, until SEOs figured out how to manipulate PageRank in various ways.
When Google stopped sharing PageRank with all of us, Moz stepped up to build a proxy metric that they dubbed Domain Authority.
DA scores range from 1 to 100, with higher scores indicating stronger domain authority.
The logic behind DA is simple: the more authoritative websites linking to your domain, the higher your DA will be.
Leading Domain Authority Metrics Compared
Now that we’ve defined the goals of this post and what DA actually is, let’s look at the top three contenders for best DA metric.
Moz: The Original Domain Authority
Moz’s Domain Authority metric was one of the first of its kind and has been widely adopted in the SEO industry.
It calculates a website’s DA based on several factors, including the number and quality of backlinks, the age of the domain, and the strength of the website’s content.
Here’s a closer look at some key factors considered in Moz’s DA calculation:
1. Link Profile:
- The number of unique domains linking to your website
- The quality and relevance of these linking domains
- The total number of backlinks, including both follow and nofollow links
2. Content Quality:
- The relevance and quality of the content on your website
- The engagement metrics, such as bounce rate and time on site
3. Domain Age:
- How long your domain has been registered: Older domains generally have higher DAs
4. Spam Score:
- Spam Score, which assesses the likelihood of your website being associated with spammy practices
Moz tells us that they update DA approximately once a month (although I am skeptical that this is true in 2024), providing webmasters and SEO professionals with a valuable tool for tracking and improving their website’s authority.
Competitive Metrics from SEMrush and ahrefs
While Moz’s DA has been a go-to metric for many SEOs, SEMrush and ahrefs have introduced their own authority metrics, offering alternative perspectives on a website’s strength.
Let’s take a closer look at these competitive metrics:
1. SEMrush: Authority Score (AS)
SEMrush uses their own metric called an Authority Score. This proprietary metric also measures relative strength of a domain.
Like Moz, SEMrush considers various factors in their calculation:
- Backlink quantity and quality
- Referring domains
- Organic search traffic
- Social signals
- Brand mentions
The SEMrush Authority Score ranges from 1 to 100, similar to Moz’s DA.
However, the specific factors and algorithms behind the scores differ slightly.
2. ahrefs: Domain Rating (DR):
ahrefs, another prominent name in the SEO industry, offers its own metric called Domain Rating (DR).
ahrefs calculates DR based on the backlink profile of a domain, similar to Moz and SEMrush. However, you’ll find differences in Domain Rating vs. Domain Authority and Authority Score.
Here are some key factors considered by ahrefs:
- The number of backlinks
- The quality and authority of linking domains
- The diversity of anchor texts
- The growth or decline of the backlink profile over time
ahrefs’ DR score also ranges from 1 to 100, making it relatively easy to compare with Moz’s DA and SEMrush’s Authority Score.
How These Metrics Differ
Now that we’ve covered the basics of these three authority metrics, let’s explore how they differ and why you might prefer one over the others for your SEO strategy:
1. Data Sources:
- Moz’s DA primarily relies on data from Moz’s own crawler and index, which they updated significantly in 2019
- SEMrush’s Authority Score incorporates data from SEMrush’s extensive keyword database and backlink analysis and may include more domains
- ahrefs’ DR is based on ahrefs’ vast backlink database
Depending on the breadth and depth of the data these platforms have, the authority scores can vary rather widely for the same domain.
2. Algorithm Differences:
- Each platform uses its own algorithms to calculate authority scores, which may result in different scores for the same website
- The weight given to specific factors, such as the quality of backlinks or social signals, can vary
3. Regular Updates:
- Moz updates DA approximately once a month
- SEMrush and ahrefs also provide regularly updated authority scores, and both appear to update more frequently than Moz
The frequency of updates can be a consideration if you need real-time insights into your website’s authority.
4. Additional Tools:
- Moz offers a range of SEO tools beyond DA, such as Page Authority (PA) and Keyword Explorer
- SEMrush and ahrefs provide comprehensive suites of SEO tools, including keyword research, competitor analysis, and more
Your choice may depend on your overall SEO needs and whether you prefer an all-in-one solution or a specialized metric.
Which Metric Should You Use?
The choice between Moz DA, SEMrush Authority Score, and ahrefs DR depends on your specific goals and preferences.
Here are some scenarios to consider:
1. If You Trust Moz’s Data and Tools:
Stick with Moz’s DA if you have a long-standing trust in Moz’s data and find their additional tools beneficial.
I have never been much of a Moz guy myself and stopped using it years ago when I found the data to be limited.
I was also frustrated that they acquired most of their tools and put them behind a login, but did not full integrate them into a unified platform. Perhaps they have fixed it by now, but I remain a naysayer.
There is also a good amount of skepticism in the industry about DA’s continued relevance in today’s semantic SEO and AI-driven world. Here’s one third party opinion you may want to consider.
2. If You Prefer a Broader SEO Suite:
SEMrush and ahrefs both offer more extensive sets of SEO tools in addition to their authority metrics.
Choose one of these platforms if you need a comprehensive SEO solution.
I am a fan of both platforms but actually subscribe to SEMrush, and am very happy with it to this day.
3. If You Want a Fresh Perspective:
To get the most well-rounded idea of what your actual domain authority is, consider trying more than one tool, or even all three, budget permitting.
You can cross-reference scores from Moz, SEMrush, and ahrefs for a more comprehensive analysis.
Conclusion: Domain Authority Metrics De-Mystified
In the world of SEO, it’s important to understand how strong your domain is and how it stacks up against other websites.
While Moz’s original Domain Authority has been a standard industry metric for years, SEMrush Authority Score and ahrefs Domain Rating offer equally appealing perspectives and valuable insights.
Ultimately, the choice of which metric to use depends on your specific needs and preferences.
Whichever metric you choose, remember that these scores are just one part of the SEO puzzle.
You will still need to address on-page optimization and user experience, while offering high-quality and authoritative content to align with Google E-A-T standards.
Now that you’ve deconstructed Domain Authority and explored its alternatives, you should feel better equipped to make informed decisions for your SEO strategy.
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