Here are three overarching categories to consider when evaluating link quality:

1. Relevance
2. Human value
3. Authority and trust

Each of these factors is complex and involves multiple layers of evaluation.

1. Relevance

The most important factor when evaluating link quality is relevance.

Links without some degree of relevance aren’t worth your time (and are likely to be considered manipulative). A good litmus test is to explain the relevance to a colleague or friend. Why would a particular site link to you? If it is difficult to provide a compelling explanation, it’s probably time to move on to a new link prospect.

Generally speaking, a link can be relevant in four different ways:

• Domain to domain
• Domain to page
• Page to page
• Link to page

These are pretty straightforward, but you can check out a post by Cory Collins (a content marketing specialist and my colleague) here to learn more about each individual type of relevance.

Determining relevance comes down to trusting your intuition. If you can’t explain to another human being why a link would make sense on another site, the relevance likely isn’t there.

2. Human Value

Worthwhile links are those that offer real value to humans.

When thinking about the human value of a given link, consider if it would make sense on the page where it’s located. Ask yourself the following questions:

• Would someone be happy they clicked your link?
• Would the link take them where they expected to go?
• Would the page provide what they’re looking for?
• Would the link take them to something useful and helpful?

A link should contribute to the overall value for the site linking, the site being linked and the person who clicked the link. In fact, if a site owner is willing to link even though it offers no clear value to their audience, that’s a red flag, and you probably don’t want a link on that site.

You need to examine the linking site’s audience when considering human value. After all, if there aren’t any actual humans reading the site, there’s no human value in a link there. Same if the wrong audience is on the site – you want to be sure the link makes sense for everyone involved and adds value to the web.

It’s possible to check audience engagement through a site’s blog or forum by checking for comments and questions submitted by readers. Once you’ve verified engagement, you can use a tool like SEMrush to check traffic numbers and determine audience size.

Links that provide genuine value to human readers are the best links you can secure, and they’re the types of links Google wants to count.

3. Authority and Trust

Measurements of authority and trust are important criteria worth examining.

Google’s search algorithm is designed to return the most authoritative and trustworthy results for a given query. Google largely uses links to determine trust and authority, and you’ll want to ensure you’re securing links on sites that send these signals. Plainly stated, links from authoritative sites will pass more authority to your site.

Only Google engineers (and maybe not even them, at this point) understand how their search algorithm measures authority (PageRank) and determines search results. But there are some tools that offer relatively accurate authority metrics.

Here are some potential options:

• Moz – Domain Authorityand Page Authority
• Majestic – Trust Flow and Citation Flow
• Check Google rankings for related terms – Ranking within Google is its own signal of authority (You can use a tool like AuthorityLabs).

These metrics shouldn’t be your only measuring stick, and context is required. For example, a new page on an industry-leading site will initially have low Page Authority simply due to being new.

Same with a new domain – an up-and-coming website generating positive engagement within an industry will still rate low on most if not all of these authority tests. But it’s worth looking at these tools to get a high-level interpretation of authority and trust.

Scrutinize the site’s link neighborhood, as well. Avoid any site that exists within a spammy link neighborhood. Use a backlink tool like Majestic or Open Site Explorer to examine a site’s backlinks.

Finally, conduct some niche research to get an idea of the site’s industry reputation. Do a quick Google search on the site’s brand or domain name and see what turns up. Or check relevant communities to see what the conversation surrounding prospective sites looks like. You can also use a mention tool to find brand mentions across the web.

A small amount of industry research can reveal a site’s reputation and help determine whether or not that site is somewhere you want a link.

Consider authority and trust signals as you evaluate link prospects, because links are endorsements online, and you should want to be in good company.

Technical Elements

As SEOs, of course we will notice the technical elements surrounding a link. Google’s original PageRank patent describes much of this, and there have been updates since.

These technical elements are important to note, but they shouldn’t affect whether you pursue a link or not, only how you report it. These elements can affect how Google interprets relevance and authority, or if they can crawl the link at all.

Some of the technical elements to consider are:

• Nofollow
• Alt attribute
• Redirects
• txt
• Javascript
• Anchor text
• Page location

Moz co-founder Rand Fishkin covers in depth most of the important factors in this Whiteboard Friday. These technical elements can and will affect the SEO value of a link.

You shouldn’t sweat these technical elements too much; the emphasis should remain on relevance, human value, authority and trust. It’s much more important to build positive relationships and earn trust from site owners, rather than raise issue with the technical elements of a link.

Conclusion

Evaluating link quality is an essential portion of successful link acquisition and monitoring search as a marketing channel.

As Google works to improve and adjust their algorithm, they are getting better at separating real links from link spam. If you want to earn worthwhile links that will make a positive impact for your site and brand, you must constantly evaluate link quality and ensure you’re securing the best links possible. In review, examine these criteria to determine link quality:

• Relevance
• Human value
• Authority and trust

Links represent endorsements online. If you’re actively marketing yourself online, you should be sure you’re receiving the endorsements you deserve — but it’s just as important to ensure they’re the reputable endorsements you want.

good vs bad

Links can significantly impact your search performance — for better or worse.

Regardless of whether you choose to use black hat or white hat link building techniques, you should be prepared for the potential consequences.It’s important to run a full backlink analysis and pinpoint both the good and bad links that are pointing to your site.You know that good links will impact your search performance in a positive way, while the bad ones can potentially harm your site.You want to avoid Google penalties as much as possible, especially now that Google is so concerned about user intent, as opposed to the keyword phrases they search for.

In the past, you could get away with any kind of links. Google frowned at bad links from the beginning, but they didn’t have a system for fishing out culprits. It’s a different ball game now.The Panda update redefined content quality. The Penguin update made it clear that Google prefers earned links over built links.Keep in mind that backlinks are important to your page’s rank or position in SERPs.After reading this article, you’ll know how to get the right links — the links that’ll improve your search rankings. Let’s get started

Evaluating Link Quality

Links are an indicator of success within online marketing. But this doesn’t mean “get as many links as possible” or “X number of links equals success.”

Links should be a KPI within your greater online marketing strategy, similar to the more generally accepted KPI (particularly for content) of social shares. Links are not the end goal, but instead a means to achieve the end goal.

In fact, links are more valuable in terms of traffic, with organic search driving 51 percent of traffic versus five percent from social (according to the BrightEdge study). And while quantity is often the goal with social shares, more isn’t necessarily better when it comes to links.

Rather, you need to evaluate the links you’re securing to guarantee quality and ensure they support your larger marketing goals. Evaluating link quality is much more difficult than spotting spammy links. Within link quality, there is a large gray zone beyond toxic versus non-toxic.