Use Impact Factors? Now try the Eigenfactor

You may be familiar with the Impact Factor which uses citation data to assess and track the influence of a journal in relation to other journals. Impact factors can be found in the Journal Citation Reports (JCR) at the Web of Knowledge.
Now the JCR has been upgraded with some new features including the new Eigenfactor Score.

The Eigenfactor Score measures the number of times articles from the journal published in the past five years have been cited in the JCR year.
Like the Impact Factor, the Eigenfactor Score is essentially a ratio of number of citations to total number of articles. However, unlike the Impact Factor, the Eigenfactor Score:

• Counts citations to journals in both the sciences and social sciences.
  
• Eliminates self-citations.Every reference from one article in a journal to another article from the same journal is discounted.
  
• Weights each reference according to a stochastic measure of the amount of time researchers spend reading the journal.

For more information about the JCR enhancements see
http://isiwebofknowledge.com/products_tools/analytical/jcr/