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Co-Citation and Co-Occurrence: The Ultimate Guide to the Next Evolution in SEO

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When you see “new big thing in SEO” in an article title, you have every right to read with skepticism. SEO is fraught with ‘new things,’ ‘big things,’ constant change, too much hype, and a lot of misinformation. Co-citation isn’t exactly new, but its latest iteration and the attendant changes that it introduces into the SEO world are a pretty big deal. This article will introduce the topic of co-citation or co-occurrence, and explain some of its ramifications.

Understanding the Terms “Co-citation” and “Co-occurrence”

Before explaining the nitty-gritty of these SEO trends, we need to explain the terms themselves. Co-citation and co-occurrence refer to roughly the same thing. The term co-occurrence is used by some SEOs to describe how keyword phrase association across sites can impact search engine results.

Co-citation more specifically addresses the issue of how sites can affect the ranking of other websites without the presence of an actual link. Based on this understanding, co-occurrence is distinct from co-citation. This article, however, uses the term co-citation to encompass both co-citation and co-occurrence.

What is co-citation? 

The big idea of co-citation is rather simple, but you have to wrap your mind around it. Here’s how it happens. Website A and Website B both link to Website C and Website D, but Website A and Website B don’t link to each other. Nonetheless, Website A and Website B are connected by means of co-citation.

Co-citation Illustration 1

This method of understanding co-citation, however, is simplistic. Co-citation also involves the transitive property, which looks like this.

Co-citation Illustration 2

Co-citation, then, establishes a relationship between two sites, even though there are no links between those two sites. The relationship of co-citation is established by contextual keywords and mutual links. Keep in mind that co-citation relationships are simultaneously happening across vast numbers of similar sites.

But there’s more to co-citation than just halo authority via transitive relationships. Perhaps the most surprising aspect of co-citation is that it can elevate a site’s rankings without links and even in the absence of actual matched keywords.

What’s the big deal about co-citation and co-occurrence? 

The reason why co-citation is such a fascinating trend is that it defies customary understanding of SEO best practices.

Here’s an example. Let’s say that a website is winning in the rankings for “best electric lawnmower.” When you visit this high-ranked website, however, you notice that it lacks the keyword “best electric lawnmower” in the title tag, in the meta description, in the anchor text, and maybe even in the content. What’s going on? There may be a few keyword synonyms, but no longtail matches, and little in the way of link juice. How in the world does this site rank so high?

The answer is co-citation.

Google associates relevant terms with such websites, even when those sites are devoid of the classic SEO signals. It then awards such sites high ranks based on co-citation markers rather than customary SEO features.

This is not to say that existing SEO practices are dead, nor are they less important. Instead, co-citation is an additional SEO reality of which we must be aware.

Two Important Truths about Co-citation

1.    Co-Citation is Fuzzy

The big thing we need to keep in mind is that co-citation resists cut-and-dried explanations of how exactly it works. There is no list of “co-citation best practices,” nor are there tools that can effectively measure co-citation. It is inherently immeasurable because of its vague nature and the aggregate algorithmic features that comprise it. Co-citation involves a host of signals that encompass a wide range of SEO features. There are additional fringe factors that bear upon co-citation as a SERP-affecting event, such as:

  • Social media signals
  • Brand and entity association
  • Increasingly effective contextual analysis by search engines
  • Growing influence of keyword proximity factors (linking context) in search engine results
  • Query volume, both for the brand/entity name and on the keyword itself

Every one of the features listed above bear upon SEO in general and upon co-citation specifically.

This simply goes to prove the point that SEO is increasingly becoming something beyond manipulation. More and more, SEO is sliding out of our grasp, and depending upon the power of the algorithms and the impact of millions of searches that people are conducting each day.

2.    Co-Citation is a Paradigm Shift

The second truth about co-citation involves its far-reaching implications.

There are two types of SEO professionals — those who use novel tricks and those who employ classic and strategic maneuvers. Those who use the cute tricks will likely see jumps in ranking, but no sustainable value. Successful SEO, on the other hand, endures. Those who use strategic maneuvers play it smart by understanding the algorithm changes and responding accordingly.

What we’re seeing in co-citation is a trend deeply rooted within a host of algorithmic components. Thus, co-citation can be considered a sustainable change that affect the way SEO is done for the long term.

What does co-citation mean for the future?

If we’re talking about a paradigm shift, what kinds of changes can we or should we expect for the future?

  • Anchor text isn’t as important anymore. Rand Fishkin’s  Whiteboard Friday video on SEO Moz alerted many in the SEO community to the growing trend of co-citation in the Google algorithms. The article contains the prediction, “Anchor text is weakening and may be replaced.” While Fishkin’s declaration may be an overstatement, he’s on to something. As co-citation rises, we may see a concomitant decline of the importance of anchor text.
  • Co-citation does not mean that SEO is dead; it’s just changing like always. The “SEO is Dead” group will always be around. In reality, SEO will live on as long there are search engines. SEO is still important, but the customary ways of optimizing may not have the importance they once held. This is nothing new, since SEO is always changing. If a page doesn’t have lots of backlinks or other SEO best practices, they may still benefit from the SEO value of co-citation. Co-citation plays into the gradual Google shift away from SEO as a system that can be gamed, and more into a humanized method of returning the most relevant search results. SEO has come a long way since the black-hat keyword-stuffing days. And it’s still coming along, meaning that many of the traditional SEO tools we’re using now (e.g., anchor text) may be passé in a few years…or less.
  • PR, Reputation Management, and brand building are always a great idea. Although SEO changes, brand awareness will always remain a strong factor. The way it plays out in co-citation is that brand awareness unleashes more mentions of your brand on the Web. As this happens, your site rankings will improve via co-citation. Your personal brand still matters, and it pays to give it due attention. It’s virtually impossible to start a co-citation campaign or “co-occurrence effort as a separate SEO strategy. Instead, it makes more sense to start a “brand awareness” campaign with a side-benefit of co-citation.
  • Links are still important. Even though co-citation doesn’t depend on links, don’t neglect link building strategies as part of your SEO approach. You need lots of links, links from authoritative sites, links from top-tier blogs, etc. In addition to link love, you’ll also profit from link-less mentions, a.k.a. co-citations. As one SEO professor put it, “co-citation just means Google is getting smart enough to realize not everyone links, but everyone talks.” Such talk is profitable.

Co-citation has not reached its maturity, but now is the time to know about it. This truth won’t revolutionize your SEO practice today, but it will have an increasing impact upon search in the future.


Jayson DeMers


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  • Travin Keith

    Great article as always Jayson! I completely agree that this is the direction SEO is going and am looking forward to it. In my opinion, it’s one of the great things about SEO, it’s always changing for the better, both for Web Marketing companies that aim for substance and for the general population.

    As for the difference between co-citation and co-occurrence, I wouldn’t be surprised if someday they’ll end up meaning the same thing as they’re already quite similar to begin with.

  • Jayson DeMers

    Thanks for the comment, Travin! I agree that eventually we’ll probably wrap them both under one umbrella term. My question is, which one will be more popular to use?

  • Travin Keith


    I personally prefer “co-citation” as it uses a term Web Marketers use all the time. It’s also pretty direct and gives a good idea of what’s going on even without looking into what it is. “Co-occurence” on the other hand seems to be too closely associated to the word “coincidence”, which isn’t really the best term to describe SEO efforts.

  • Jayson DeMers

    I like your rationale, and I agree. Co-citation it is!

  • Jack Thomas

    If Co-citation is a method for ranking that would mean that Google is now tracking ‘words'(keywords) in a way that has never been done before correct? I’m not 100% convinced Co-citation is real, could it be possible that the co-citations were actually a white Herring, an Aberration? (I.e. lack of competition for the keywords in the example)

    What are your thoughts Jayson?

  • Samuel Junghenn

    Great article Jayson, good to see someoen that can explain what Co-Citations are in a succinct way.

  • Spook SEO

    Now that explains everything about Co-citation and Co-occurrence, very simple and organized thank you Jayson much appreciated! But these two bothers me, with the current Algorithm update is this still functional and rationale to be used? Or can we really benefit in an SEO manner if we use these strategies?



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