The Eigenfactor is a rating of the importance of a scientific journal. In a manner reminiscent of Google's Pagerank algorithm, journals are rated according to the number of incoming citations, with citations from highly-ranked journals weighted to make a larger contribution to the eigenfactor than those from poorly-ranked journals.
Eigenfactors are calculated by , where they can be freely viewed; they are intended to give a measure of how likely a journal is to be used, and are thought to reflect how long the average researcher would spend reading content from that journal.
The Eigenfactor approach is thought to be more robust than the impact factor metric, which purely counts incoming citations without considering the significance of those citations. However, the two metrics have been shown to be strongly correlated for medical journals.

Eigenfactors are sometimes misused to rank individual scientists. This is a mistake because even prestigious journals sometimes include poor-quality or fraudulent papers, which make little impression on the overall eigenfactor. The H-index is considered the most robust indicator of a scientist's productivity.