The Eigenfactor calculation is based on the number of times articles from the journal published in the past five years have been cited in the JCR 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 Eigenfactors are not influenced by journal self-citation.
A citation matrix is created that records citations from each journal to each journal (dropping self-citations). The citing year = JCR year. The cited period is the 5-year window prior to the JCR year (identical to the 5-year Journal Impact Factor).
For further detail on calcuation of the Eigenfactor, please see the Eigenfactor website: http://www.eigenfactor.org/methods.php
The value of the Eigenfactor is similar to the Journal Impact Factor or the 5-year Journal Impact Factor. Unlike those, the Eigenfactor assigns weight or value to each earned citation, according to the citedness of the citing journal. Consider two journals: Journal A is highly cited; Journal B is poorly cited. Cites coming from Journal A are given greater weight when the Eigenfactors for journals B-Z are being calculated and cites from Journal B are given less weight when calculating Eigenfactors for journals A & C-Z.
The Eigenfactor, much like the Journal Impact Factor and 5-year Journal Impact Factor is a publication-level metric. It does not apply to individual papers or subgroups of papers that appeared in the publication. Additonally, it does not apply to authors of papers, research groups, institutions, or universities.