Wednesday, 18 February 2009

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


Anonymous said...

A useful summary - thank you!

Ruth J

Alison Johnson said...

Anyone interested in impact factors and measurement might like to know about a forthcoming seminar:

Measuring up - the evolution of impact metrics

15 June 2009, London

Run by the Association of Learned and Professional Society Publishers, this seminar will explore the evolution of impact metrics, examining strengths and weaknesses and the implications in a society increasingly focused on measuring research quality. Moving forward from the impact factor, it will cover usage (download) measurements from the MESUR project; author level indices such as the Hirsch index and derivatives; and eigenvector (PageRank) style metrics such as the EigenFactor and the SCImago Journal Rank Indicator.