Day 27 – Eigenfactor (Assessment)

It’s Day 27 and we’re in the home stretch of our 30 day tour! Today we’ll look at the Eigenfactor Project, which provides Eigenfactor scores that measure a journal’s importance and ranking within the scientific community, much like the better-known journal Impact Factor provided by Thomson Reuters through the publication Journal Citation Reports (JCR).

Eigenfactor metrics use information from the citation network to measure the importance of each journal, much as Google’s PageRank algorithm measures the importance of websites.  It accounts for the fact that citations are not all created equal – that is, a citation from Science should count for more than a citation from the Journal of Underwater Basket Weaving, as Phil Davis memorably says in his blog post.

Eigenfactor Metrics consist of two scores, the Eigenfactor score and the Article Influence score.

The Eigenfactor Score calculation is based on the number of times articles from the journal published in the past five years have been cited in one year, but it also considers which journals have contributed these citations so that highly cited journals will influence the network more than lesser cited journals.  References from one article in a journal to another article from the same journal are removed, so that Eigenfactor Scores are not influenced by journal self-citation.

The Article Influence determines the average influence of a journal’s articles over the first five years after publication.  It is calculated by dividing a journal’s Eigenfactor Score by the number of articles in the journal, – a ratio of a journal’s citation influence to the size of the journal’s article contribution over a period of five years.
– from Journal Citation Report‘s Help pages (Eigenfactor metrics are included alongside JCR’s impact factor metrics)

eigenfactor detail.pngFree of charge, the journal ranking site at provides the Eigenfactor metrics for every journal in the Thomson-Reuters Journal Citation Reports database since 1996. You can search for individual journals, rank journals by field (their ‘ISI category’) and track changes in influence over time – see this example for the Journal of Neuroscience.

The Eigenfactor project is a grant-funded research initiative begun in 2007 by two researchers at the University of Washington, Carl Bergstrom and Jevin West. Among their other research projects, the two study the sociology of science, scholarly publishing, and the structure and visualization of scientific networks.

Information from and from Journal Citation Report‘s Help pages was used in writing this blog post.

Read more:

Bergstrom, C. T., West, J. D., & Wiseman, M. A. (2008). The Eigenfactor™ Metrics. The Journal of Neuroscience, 28(45), 11433–11434.

Davis, P. (2008, July 23). Eigenfactor. Retrieved from






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