Eigenfactor.org is a non-commercial academic research project sponsored by the Bergstrom lab in the Department of Biology at the University of Washington. Eigenfactor ranks journals much as Google ranks websites. Scholarly references join journals together in a vast network of citations. Eigenfactor uses the structure of the entire network (instead of purely local citation information) to evaluate the importance of each journal.
As part of the Eigenfactor project and using data from Thomson Scientific's 2004 Journal Citation Reports (JCR), the authors developed a map of the sciences and social sciences based on 6,434,916 citations among 6128 journals over a five year period. For sake of simplicity, the authors showed only the most important links, namely those that a random surfer traverses at least once in 5000 steps, and the modules that are connected by these links. Orange circles represent fields, with larger, darker circles indicating larger field size as measured by Eigenfactor. Blue arrows represent citation flow between fields. An arrow from field A to field B indicates citation traffic from A to B, with larger, darker arrows indicating higher citation volume.
This map is based on an information flow method for mapping large networks which identifies important structures (in this case, clusters of journals that compose research fields) within a very large network. We can then make a map of the network that simplifies away the unnecessary details while highlighting the important structures and the relationships among them.