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Measuring Research Quality and Impact: Journal Impact Factor
& Other Rankings

Tips, techniques & links to help you find answers for your research papers & projects

Impact Factor (IF)

Definition: A measure of the frequency with which the "average article" in a journal has been cited in a particular year or period. Thomson Reuters

Calculation: 2012 impact factor = A/B.
A = the number of times articles published in 2011 and 2012 were cited by journals indexed by Thomson Reuters' Web of Science during 2012.
B = the total number of "citable items" published by that journal in 2011 and 2012

Available from: Journal Citation Reports/JCR

Caveat:  Only journals in the sciences and social sciences that meet Thomson Reuters standards for inclusion in the Web of Science Core Collection are assigned impact factors.  Impact factors are not computed for journals in the humanities.

On going Debate:  Currently impact factors are the most widely known way to rank journals, however, they are controversial.  Some people believe that impact factors do not accurately reflect the impact of a journal or article. 
(Hate journal impact factors? New study gives you one more reason, Science July 6, 2016)


Definition: CiteScore is the number of citations received by a journal in one year to documents published in the three previous years, divided by the number of documents indexed in Scopus published in those same three years. Scopus

Available from: Scopus Journal Metrics

  • CiteScores are computed for all journals indexed by Scopus  (over 22,000 titles).
  • CiteScores are computed for journals in all disciplines including the humanities.


Definition: Ranking based on incoming citations for a journal with more weight given to citations from significant and larger journals.

Available from:  Journal Citation Reports/JCR and Eigenfactor Search

Further information: Eigenfactor: Detailed Methods (2007)

Journal Rankings by Discipline

Article Influence

Definition:  A measure of the average influence of each of a journals' articles over the first five years after publication. 

  • It is the journal's Eigenfactor score divided by the fraction of articles published by the journal.That fraction is normalized so that the sum total of articles from all journals is 1.
  • The mean Article Influence score is 1.00. A score greater than 1.00 indicates that each article in the journal has above-average influence. A score less than 1.00 indicates that each article in the journal has below-average influence.

Available from: Journal Citation Reports/JCR and Eigenfactor Search