Analyzing Domain “Authority”: How Ahrefs DR, Moz DA, Semrush AS, and Majestic Metrics Differ. 150 websites case study.
The website authority measurement by various SEO tools can be totally different. Actually, they are
The website authority measurement by various SEO tools can be totally different. Actually, they are mostly very different, sometimes varying from low single-digit to 50+ for the same domain.
For the same website, different authority metrics show totally different scores.
My team completed the most extensive authority metrics research online last year. We tested the leading SEO tools across various parameters, including speed, sensitivity, and resistance to manipulating their website authority metrics.
This research is designed to be the final piece, pulling together data from 150 websites into a study that shows how various domain authority metrics work in real life.
The questions we answered in this research:
- How much can metrics vary for the same domain?
- Which metrics are the most optimistic, and which are conservative?
- Why are they so different?
- Can we “convert” one to another?
- What is the most reliable metric?
Our guinea pigs domain selection:
To answer our questions, we took three groups of websites representing real-life market players and potential users of the domain authority metrics:
- Top Authority Websites: We chose 50 random websites from 500 companies in the S&P 500 index. These are the biggest publicly traded companies in the US, so their websites are assumed to have high authority due to their age, size, and importance.
- Small Businesses: We picked 50 random websites out of 6,271 from the Flippa database. Those are real and profitable online businesses, primarily small and driven by solopreneurs or small teams. This group is a key user of domain authority metrics used to measure their performance or evaluate backlinks for marketing purposes.
- Link Donor Websites: We selected 50 random websites from link-building companies. We obtained lists of thousands of link donor websites from 61 link-building providers and randomly picked 50 from these lists. They mostly use authority metrics as a value indicator when selling website links.
In summary, we studied 150 domains – 50 websites from S&P 500 companies, 50 small business websites from Flippa, and 50 link donor websites from link-building companies.
Before diving into the numbers, let’s step back for a second and take a helicopter view of the market.
Businesses love to measure authority!
Domain Authority is a common value indicator in the online business world. In the US alone, people Google how to check and grow it almost 50,000 times a month.
Source: Semrush Keyword Magic Tool.
Moz introduced the concept and DA metric in 2004. Over time, “authority” evolved into a broader framework to measure and highlight a website’s authority in Google’s “eyes.” Various SEO tools introduced their own algorithms and metrics to measure it.
| Authority Metric | Year of Introduction |
| Moz DA (Domain Authority) | 2004 |
| Majestic TF (Trust Flow) | 2012 |
| Ahrefs DR (Domain Rating) | 2016 |
| Semrush AS (Authority Score) | 2018 |
High website authority is widely used as a selling point for link building, digital PR, online business, and domain transactions. The websites with higher scores are priced for top dollar.
An example of link-building package pricing offered by link builders.
It’s hard to compare apples to apples.
It’s important to know that comparing different domain authority metrics is challenging because each one is calculated differently. Here are the key differences between them.
| Factors In | Moz DA | Majestic TF | Majestic CF | Ahrefs DR | Semrush AS |
| Link Quantity | ✔ | ✖ | ✔ | ✔ | ✔ |
| Link Quality | ✔ | ✔ | ✖ | ✔ | ✔ |
| Organic Traffic | ✖ | ✖ | ✖ | ✖ | ✔ |
| Spam Factors | ✖ | ✖ | ✖ | ✖ | ✔ |
As you can see, each authority metric is calculated differently by factoring in different parameters. So, even from an algorithm perspective, they were not designed to be equal.
The table above explains many variations in the research results. For example, the largest deviation in results within the Link-Building group is primarily explained by Semrush AS’s ability to factor in organic traffic.
Since many link donors have no traffic, their Authority Score is driven to lower values.
Also, if the backlinks from other websites to link donors have no organic traffic or the percentage of do-follow links is high, Semrush further reduces the score, considering anomalies indicate spam.
Let’s get back to the research results now!
How much can website authority metrics vary?
If you want to remember the only conclusion from this article, it should be this:
The Authority metrics from different tools are mostly completely different for the same website.
Take a look at this beauty! The chart below has 600 dots, each representing one measurement. The dots are color-coded in orange (Semrush), blue (Ahrefs), green (Moz), and black (Majestic).
As you can see, while the general trend is visible, the colored dots are very far from plotting a line!
Scatter plot of domain authority scores for 150 sites – 50 Flippa sites, 50 Link donor sites, and 50 S&P500 sites.
Some math and examples:
1. The average Range through 150 websites was 26 points. This means the average difference in measurement for the same website between the highest score from one tool and the lowest from another.
2. The most extreme example in the S&P 500 group was coca-colacompany.com, with a Range of 39 points. Website authority measured by Majestic TF/CF was 46, and Moz DA was 85. You can see how different results are even for the biggest companies in the US!
The domain authority scores for Coca-Cola website ranges from 85 (Moz DA) to 46 (Majestic CF).
3. A website can have an AS of 5, a DA of 70, and a DR of 51. One of the link donors we’ve analyzed had a Range of 65!
The domain authority scores were too varied for link donor sites. In this example, the site has a Moz DA of 70 and Semrush AS of 5!
By the way, checking this domain with Ahrefs will show zero rankings and traffic. Nevertheless, it’s still considered “authoritative” by their metric.
A link donor site with DR 51 and zero traffic. Source: Ahrefs.
I’ll dive deeper into this phenomenon one day, so stay tuned!
Let’s remember that authority metrics are very different in their algorithms and the results measured.
Optimistic vs conservative
Here is the average authority of 150 sites in total and divided by group:
Average domain authority scores grouped by site type and authority metric.
Ahrefs and Moz tend to show the highest authority numbers, Semrush tends to be the most conservative, and Majestic is somewhere in between.
The only exclusion was the S&P 500 group, where Semrush averaged 2 points above Majestic.
The difference is significant. The average deviation between Semrush AS (34) and Ahrefs DR / Moz DA (~50) is more than 30%.
That’s a lot. Especially for link-sellers.
On average, a link from a site with an authority of 20-39 costs $150-200, while a site authority of 60-69 costs $400-$550. That’s a 100%+ difference per link.
No wonder most link-sellers prefer either DR or DA to justify their price!
Maximums and Minimums
Let’s examine these scores on the group level.
Maximums:
Percentage distribution of sites by their highest scoring authority metric. Few sites have the same scores in different DAs and are hence counted in both these metrics.
Ahrefs gives the highest authority in 50% of cases – more often than any other website authority checker. This is followed by Moz, which has 31%.
Semrush and Majestic are more conservative, giving the highest scores in 9% and 13% cases, respectively.
They are especially skeptical about link donors—neither tool has ranked the link donor authority above the values that Ahrefs and Moz gave.
Speaking of link donor sites:
32% of link-donor sites have zero organic traffic. 70% have less than 1000 monthly visits.
In the vast majority (81.2%) of cases, Moz gave the highest authority to the website with zero traffic. Sometimes Ahrefs. But never Majestic or Semrush.
Minimums:
Percentage distribution of sites by their lowest scoring authority metric. Few sites have the same scores in different DAs and are hence counted in both these metrics.
Looking from the other side, Semrush AS scored 63% of the sites, the lowest, followed by Majestic TF/CF at 25%.
The skew is even more noticeable for link donor sites. Semrush AS did not score any of these sites the highest and scored 92% of them the lowest. Interestingly, Ahrefs DR and Moz DA never scored the link donor sites the lowest.
Bottomline
Website authority metrics vary a lot when measured by different tools.
Ahrefs and Moz tend to show similar numbers and are also on the higher end of the spectrum in most cases.
Semrush is the most conservative tool for evaluating authority, followed by Majestic.
There’s no way to “convert” metrics to each other due to differences in their algorithms.
No metric should be used as a sole measurement of the website authority. However, considering our previous experiments with the domain authority metrics manipulation, Semrush AS tends to provide the most reliable (yet usually pessimistic) score.
Comments or suggestions?
Max Roslyakov
Founder, Xamsor