Bibliographic Coupling

Bibliographic coupling or co-citation occurs when two works reference a common third work in their bibliographies. It is an indication that the two works treat a related subject matter.

Measuring bibliographic coupling can be useful in a wide variety of fields since it helps researchers find related research done in the past, though its exact interpretation may vary depending on the field, since different fields have different citation practices. There are various metrics of bibliographic coupling, usually calculated using citation indexes. The coupling strength of two given documents is higher the more citations they have in common. The co-citation index is the number of times two works are cited together in subsequent literature.

The concept of "bibliographic coupling" was first introduced by M. M. Kessler of MIT in a paper published in 1963, and has been embraced in the work of the information scientist Eugene Garfield. Others have questioned the usefulness of the concept, pointing out that the two works may reference completely unrelated subject matter in the third.

Some examples of online sites that make use of bibliographic coupling include The Collection of Computer Science Bibliographies and CiteSeer.IST

There was a progression of citation study methods from:

• Bibliographic coupling (1963) to
• Co-citation analysis (1973) to
• Author co-citation analysis (1981).

In 1973, Henry Small introduced what he concluded was a better indicator of subject similarity, document co-citation analysis.

In 1981 Howard White and Belver Griffith moved to author co-citation analysis (ACA).

For an interesting summary of this progression of the study of citations see. The paper is more like a memoir than a research paper, but it is full of decisions, research expectations, interests and motivations—including a really great story of how Henry Small approached Belver Griffith with the idea of co-citation and they became collaborators, mapping science as a whole.