Eigenfactor: Measuring the Value and Prestige of Scholarly Journals

In C&RL News, May, 2007 Carl Bergstrom writes about Eigenfactor <http://www.eigenfactor.org/>, a tool he developed with colleagues to use the network structure of citations to improve on simple citation counts in measuring the scientific influence of academic publications. Excerpts:

The scientific literature forms a network of scholarly articles, connected by citations. Each connection in this network—that is, each citation—reflects the assessment of an individual scholar regarding which papers are interesting and relevant to his or her work. Thus contained within the vast network of scholarly citations is the collective wisdom of hundreds of thousands of authors. My colleagues4 and I have developed a way to use the network structure of citations to improve on simple citation counts in measuring the scientific influence of academic publications. At our Web site www.eigenfactor.org, we report these measures for the nearly 8,000 publications indexed by Thompson Scientific’s Journal Citation Reports (JCR) as well as for the approximately 110,000 other journals, books, newspapers, and other reference items that are referred to by these publications.

Our approach is to rank journals much as Google ranks Web pages. While Google uses the network of hyperlinks on the Web, we use citations in the academic literature as tallied by JCR. By this approach, we aim to identity the most “influential” journals, where a journal is considered to be influential if it is cited often by other influential journals. While this might sound hopelessly circular, it is not: we can iteratively calculate the importance of each journal in the citation network by a simple mathematical algorithm.

This iterative ranking scheme, which we call Eigenfactor, accounts for the fact that a single citation from a high-quality journal may be more valuable than multiple citations from peripheral publications. We measure the importance of a citation by the influence of the citing journal divided by the total number of citations appearing in that journal. This corrects for differences across disciplines and journals in the propensity to cite other papers. For example, a citation from a review article that has cursory references to large numbers of papers counts for less than a citation from a research article that cites only papers that are essentially related to its own argument. . . . MORE