Is Co-Citation a Google Search Ranking Factor?
If you have heard of co-citation but have absolutely no idea what it is, you are not alone. Even if you know what co-citation refers to, chances are you’re in the dark as to its SEO value.
Roughly summarised, co-citation is used by search engines to figure out how two or more pieces of content may be connected.
For example, a top-rated financial publication posts a link to your website today, and then posts another link to a similar website tomorrow owned by someone else. The fact that they have posted links to both of your websites does not necessarily indicate a relationship between you and the third party in question.
However, it does provide some indication that there is some common ground between the two websites. As you have both of your sites linked to by the authority page, you most likely have something in common.
The question being, does the whole thing add up to a ranking factor with Google?
A Contentious and Continuous Debate
The short answer is we simply do not know, co-citation is a subject that has been discussed by SEOs and website owners for many years.
Over the course of the debate, some have been quite adamant about the potential for co-citation to influence SEO performance.
A quote from SourceForge, originally extracted by Jim Boykin as long ago as 2006:
“Bibliographic Co-Citation is a popular similarity measure used to establish a subject similarity between two items. If A and B are both cited by C, they may be said to be related to one another, even though they don’t directly reference each other. If A and B are both cited by many other items, they have a stronger relationship. The more items they are cited by, the stronger their relationship is.”
From a purely logical perspective, you would indeed assume that Google uses these kinds of relationships as ranking factors. Google’s job is to provide its users with links to the most trustworthy, authoritative, reputable and relevant sites.
Where there are indirect relationships between sites courtesy of an authoritative intermediary, it says something about their own authority and value.
The sophistication of Google’s search algorithm is such that taking factors like these into account would be a piece of cake. Particularly given how much emphasis Google places on quality links, one of the most influential ranking factors of all.
A quote from Jennifer Van Iderstyne in 2010, which summarised this quite eloquently:
“One of the things that can affect the value of a link, are the links surrounding it. Simply put, having your link surrounded by crap is going to make you look bad. But having your site linked to alongside competitors, or trusted resources can have a positive effect on your rankings.”
If you associate yourself with trusted websites of high authority, some of the glory is reflected on you. By contrast, become best friends with low-quality websites and it does not cast your own site in a particularly positive light. Google may have never confirmed that co-citation is a ranking factor, but logic and common-sense dictate it most probably is.