Co-citation is an indicator used to measure semantic relatedness between two documents based on how frequently they are mentioned by other documents alongside one another.
In simple words, a co-citation occurs every time two publications are cited together by any other document. And the more such common citing documents they have, the more semantically related the two cited documents are considered.
Co-citation vs bibliographic coupling
In citation analysis (i.e. analyzing frequency and patterns of citations to establish relationships between documents in a document set), the terms co-citation and bibliographic coupling are closely associated.
While co-citation presupposes that one document is referring to two others, bibliographic coupling, on the contrary, means two documents have one common document they refer to.
What is author co-citation analysis?
Citation analysis has multiple areas of focus, from journal rankings to measuring the impact of the best scholarly works to analyzing legal documents. Alongside those multiple usages, there’s author co-citation analysis.
The term refers to measuring the number of times any author's work is co-cited by another author. The co-citation patterns are then used to identify, trace, and illustrate the intellectual structure of an academic discipline.
What is a co-citation network/map?
For the purposes of co-citation analyses, the so-called citation graph is built, or, in other words, the network of documents interconnected with each other through citations.
The constructed network forms closely connected clusters of co-cited documents, which tend to share some common theme.
Co-citation and SEO
Co-citation is a term also frequently associated with SEO, since methodologies similar to citation analysis are likely to be used by major search engine algorithms to clusteryze webpages by topics and thus determine their relevance to different search queries.
The dispute, however, is whether search engines rely on hyperlinked citations or whether they are able to identify and calculate unlinked citations as well.
The former is obvious from the commonly known role of backlinks in search engines’ algorithms. While the latter is sometimes mentioned in Google patents, and in public speeches of Google representatives.
In any case, the concept of co-citation has influenced the basic principles of SEO link building, giving birth to co-citation link building - actively pursuing web mentions in the same articles where key competitors’ are being mentioned. Thus, being co-cited by the same source, a website might get a semantic association with an established industry leader.