Backlink Analytics on SEMrush uses the following four metrics to measure the impact of a webpage or domain’s links.
Authority Score is our compound metric that scores the overall quality of a domain. The score is based on the following SEMrush data:
You can use this metric to understand how beneficial a backlink from a referring domain is to your website’s SEO, or how beneficial a new backlink would be from a domain that you are hoping to build a link from.
Since Authority Score uses Page Score, Domain Score, and Trust Score in its calculation, Authority Score is the most well-rounded score to use when evaluating domains. it indicates not only the amount or quality of backlinks but the strength and popularity of the domain.
However, you may still want to know how we calculate the other scores. Below are their explanations.
Page Score and Domain Score measure the importance of a web page or domain based on the volume of links pointing back to the page or domain.
We calculate these scores similar to the way Google PageRank was calculated. Volume represents link “weight,” or the cumulative number of backlinks pointing to the page that points to the target page.
(image courtesy of wikimedia commons)
In this picture, you can see how the size of the face (representing the PageRank of a webpage) is proportionally larger based on the number of other webpages that are pointing to it.
Domain Score is calculated for the entire domain, while Page Score is calculated for an individual page (URL). The quality of links are not taken into account to calculate this metric; only the volume.
Trust Score measures the trustworthiness of a webpage or domain based on the number of links coming from highly trusted websites.
Since Trust Score places more emphasis on high quality backlinks, if you notice a big difference between Trust Score and Page Score on your website, you may be a victim of having too many low quality backlinks.
Since the quality of backlinks plays an important role in SEO, you’ll want to use Trust Score to understand which link prospects will be more or less beneficial to acquire.
Please note: Trust Score in the Backlinks report will represent the quality of the source page, while Trust Score in the Referring Domains report will represent the quality of the source domain.
Since the impact of a link is dependent on how relevant the link is, it is hard to say a backlink needs to reach a concrete number with Page Score or Trust Score to be effective. In general, somewhere over a score of 20 (for both metrics) can be considered healthy, and as the score increases, the impact of a link will increase. However, the impact of a link also strongly depends on your website’s niche.
The main use for these scores is to compare and sort. For example, use these scores in the Backlinks Report or Bulk Backlink Analysis to compare the trust levels of multiple websites. By comparing these scores you can evaluate which domain’s link profile is strongest and will send the most link weight when linking to other sites.
If you compare the Trust Score to the Page Score or Domain Score of a site and notice that the Trust Score is much lower than the Domain Score, it can be a sign of unhealthy links or cheap link building tactics. When Google sees a website with a high number of low quality links, they are inclined to give the website a Google Penalty. To avoid receiving a Google Penalty, you can run a Backlink Audit and create a disavow list to remove your website’s potentially harmful links.