Link metrics are (understandably) the starting point that most SEO professionals begin with when assessing a number of outreach targets.
While link metrics are not full proof by any means, they provide a useful way to broadly collate your outreach targets into some kind of order of priority.
However, becoming overly reliant on link metrics alone can be, at best, less impactful and, at worse, be a downright dangerous strategy that could end with catastrophic consequences for the site you’re link building for.
Finding the right balance between authority, relevance, and traffic value is key in developing a successful link building strategy.
Effective link building is instrumental in getting sites to rank well in Google. When targeting a list of potential link partner sites, how do you separate the good from the bad?
The answer is to use link metrics with caution and only in conjunction with your own expert judgment.
Common Link Metrics
There are many different metrics SEO professionals can use to measure their link building activities.
As with everything in life, some are better and more valuable to us than others.
In essence, link metrics provide you with a programmatic measurement relating to the site you are looking at.
For example, the kind of insights you can ascertain include:
- The volume of backlinks a page or site has.
- The quality of backlinks a page or site has.
- The approximate amount of traffic a site gets.
- How spammy a site is or isn’t.
Below is a summary of the most common metrics SEO pros tend to use when undertaking an outreach campaign:
Page Authority by Moz
Page Authority (PA) is a score that has been developed by Moz and is a figure that depicts the likelihood of a certain page ranking.
The page is scored between one and 100 using a logarithmic scale. The higher the figure, the more likely a page is to rank.
For example, a popular page on the BBC website could have a Page Authority of around 50+ (once it’s been live for a few months), whereas a new page posted on a local newspaper website would have a much lower PA.
A “good” or “bad” Page Authority is subjective in reality and the score is best used comparatively in order to find the most effective page or site to build a link from.
By building quality and relevant links from pages with a higher PA score, you’re more likely to positively influence the authority of your own page.
Always remember though, a new page on a website will start with an initial PA of 0.
Once the page is indexed and scored by Moz, you will (over time) start to see the true PA of the page. This can take a few weeks at least.
Domain Authority by Moz
Domain Authority, or DA as it’s commonly referred to, is another Moz metric that operates in a similar fashion to Page Authority.
However, instead of measuring the likelihood of a page ranking, it predicts how likely an entire domain will rank.
DA is a popular metric used to measure the authority of a site. Many clients and SEO teams will set a minimum DA when link building and it’s generally a useful marker when initially deciding which sites to earn backlinks from.
Sites with a higher DA tend to have a number of high-quality backlinks pointing to them.
Again, sites like the BBC, Google, and CNN have a high DA, while smaller businesses and startups generally won’t yet have accrued anywhere near the same volume authoritative backlinks and therefore will have a lower Domain Authority.
Quality Over Quantity
Obtaining a higher DA relies upon quality over quantity. A large number of low-quality backlinks will in fact be harmful to your score, particularly if the links are coming from irrelevant sources.
One point to note about DA is that it is also important to consider where on a website your link appears.
For example, you could earn a link on a news publication with a DA of 95 from a singular new page, that is one of a hundred or so new pages published that day.
If no other domains link to that page, then it will effectively become siloed.
Contrast this to getting a link from a DA 70 site but on a page that has been live for 15 years and is linked from the homepage.
A link like this is likely to be much more valuable than the one from the news publication as it is well linked internally and will have already accrued lots of authority.
Spam Score by Moz
Spam Score is a metric that gives an indication of the percentage of spammy links pointing to a site.
The score, which can be accessed through Moz’s Link Explorer tool, uses 27 common features taken from sites that have been penalized or banned by Google.
You can then breakdown your inbound links, monitoring their Spam Score, which can then be investigated further and disavowed if you so choose.
Some of the factors Moz consider in their Spam Score include:
- Number of Pages: Domains with a small number of pages are common in spammy sites.
- Google Tag Manager: Tag manager is rarely present on spammy sites.
- Contact Details: The presence of a telephone number and email address is usually a sign that a site is real.
- HTTPS: Few spam sites are investing in SSL certificates, so if a site is HTTPS it is usually a good sign.
- External Outlinks: Spammy sites often have either unusually high or low external outlinks.
- Presence of Poison Words: Spammy sites are often associated with certain niches and Spam Score looks out for poison words within topics such as adult content, gaming, and pharmaceuticals.
In our experience, Spam Score is a somewhat unreliable metric as we have found sites that for example may not have updated their SSL certificate but are still ranking well with good content.
Furthermore, some of the automated factors it looks at, such as a “telephone number and email address” just create too many exceptions. In short, we find traditional link metrics much more useful.
Trust Flow by Majestic
Trust Flow is a metric from Majestic that measures how trustworthy a site is by calculating the number of other trusted sites link into that particular page.
Majestic collated a number of seed or trusted sites and state that “sites closely linked to a trusted seed site can see higher scores, whereas sites that may have some questionable links would see a much lower score.”
While a higher Trust Flow is intrinsically a good thing, it should be used in tandem with Citation Flow.
Citation Flow by Majestic
Citation Flow works hand in hand with Trust Flow as mentioned above.
As a standalone metric, it isn’t one that is overly worthwhile reporting back to a client, as it doesn’t really become as relevant unless compared with the same domain’s Trust Flow.
A ratio of 1:1: is very good. In cases where the Trust Flow score exceeds that Citation Flow score, the site can be considered particularly authoritative (although not always desirable).
However, if a site has a Citation Flow that far exceeds the Trust Flow, it’s a sure sign the site has a high volume of low-quality links pointing at it.
Domain Rating by Ahrefs
Domain Rating is a similar metric to DA but is delivered by Ahrefs.
Highlighting the strength of a website’s backlink profile on a scale of 0 to 100, the metric looks at the “link popularity” of a website.
The way it is calculated is by analyzing how many unique domains that have a followed link to a particular site. The Domain Rating is then taken from those domains and a score is calculated using Ahrefs’ own formula.
Nofollowed links aren’t taken into account with DR and only the first link from a particular domain affects your DR score.
Organic Visibility by SEMrush
Knowing the organic visibility of a website is essential when building links and often something that is often overlooked.
We have found that earning links from sites with high traffic volumes are more lucrative compared with links from sites with lower traffic volumes.
Although this is just our experience and not a definitive rule, one thing you must avoid is getting links from sites with no visibility whatsoever as it is likely that sites like this have been penalized.
SEMrush defines their visibility metric as “showing how often your website is found on the Internet”.
The metric calculates every keyword the domain is ranking for and then produces a traffic score accordingly.
The Limitations of Relying Solely Upon Link Metrics
While it’s important to use metrics to sift through an initial list of outreach targets, there are a number of important limitations to be aware of.
Many link building metrics won’t tell the whole story, and in many cases, SEO professionals can become so transfixed on metrics they forget the overall goal – increasing visibility, rankings, and traffic.
When looking at link metrics, it’s prudent to consult a range of different tools in order to gather as much information as possible.
That said, your own judgment and assessment are equally as important as any set of metrics data.
Below are some examples where an over-reliance on link metric(s) could lead you to make a bad decision about whether to outreach to a site or not.
- You may have a high visibility score according to SEMrush, but the domain in question could be attracting completely the wrong target audience. Here, you need to look at the topical relevance of the site, something which Majestic can help with but again, the human eye is really what you should be relying upon
- Sites can have strong link metrics but have little value in terms of traffic and visibility. These sites should certainly be avoided and are even likely to have been, or be, penalized. We have seen sites with DAs of over 40 or 50 with almost no visibility.
- Moz’s Spam Score is affected by (among other things) outbound, nofollow links. This can be a problem when building links with real blogs that see plenty of engagement in the comment section. They could be viewed as spam and have a negative impact on the metric, despite the fact users are engaging with the content positively. Moreover, Spam Score is also impacted by whether a site uses SSL. It means that sites like http://law.uky.edu/ which has a DA of 71 get a spam score of 7% (despite it being a law school at a university).
- A brand new site may have a low level of authority but this might grow quickly in the future if they create great content. In fact, you may find it easier to get featured on a site which is relatively new as fewer people will be aware of the site itself.
- Dropped domains (or domains that have a number of other sites redirecting to them) are often used to hoodwink visitors into thinking the site is more authoritative than it is. The link metrics of the site will reflect the equity of the redirected domains but often this will not be reflected in the visibility score.
Examples in the Wild
| Site | Domain Authority | Trust Flow | Citation Flow | SEMrush Traffic |
| theroxyonsunset.com | 44 | 17 | 42 | N/A |
| thealmostdone.com | 41 | 18 | 31 | 3,600 |
| botw.org.uk | 32 | 34 | 45 | 1,100 |
| articlecity.com | 48 | 51 | 44 | 1,100 |
Above you can see four sites whose link metrics are in no way commensurate with the SEMrush traffic score.
While you might say an article submission site is an extreme example (given that most SEO professionals worth their salt would not go near one), this does demonstrate the fallacy of relying entirely on link metrics alone.
The site with no visibility at all (theroxyonsunset.com), used to be a local theater in Hollywood, but is now being used as a travel site.
When we crawled it, we found it was linking out to several reputable travel and tourism businesses (whether they sanctioned or were even aware of links is another matter).
The point is a link from a site like this is extremely undesirable – you are basically getting a link from a high “authority” site that has no visibility whatsoever.
Should We Just Abandon All Metrics?
Do you agree with what we are saying?
Do you have your own opinions on metrics and how we should measure the domains we are looking at for link building?
Let’s continue the conversation in the comments.
More Resources:
