Created March 2011

1. Using Impact Factors in Research & Publication Rebecca K. Miller College Librarian for Science, Life Sciences, and Engineering Virginia Tech March 2011

2. What is the impact factor (IF)? Impact factors measure the average number of citations to articles for many journals in the sciences and social sciences Overall, impact factors indicate the relative significance and influence of a particular journal within its field of research/discipline

3. Journal Citation Reports Impact factors are calculated yearly, and published in the annual Journal Citation Reports (JCR) This publication lists the impact factors for all journals (over 11,000) indexed in the ISI Science Citation Index (Web of Science), and groups journals by discipline Both of these resources are owned and managed by the publisher Thomson Reuters Access JCR through University Libraries: http://dsp.lib.vt.edu/dsp/index.php?action=ViewDatabase&did=3676

4. Finding the IF Impact factors can be found by browsing the most recent Journal Citation Reports Impact factors can also be found through individual records in ISI Web of Science...

5. Finding the IF: Demonstration Click here to view a demonstration of using JCR to find impact factors (1:00, no audio) Click here to view a demonstration of using ISI Web of Science to find impact factors (1:19, no audio)

6. Use of the IF Impact factors help you determine the most authoritative and influential journals in a particular field Use impact factors to locate the most influential research in a specific discipline Use impact factors to select the best journals to submit your research to for publication Impact factor, and related metrics, often contribute data to faculty evaluation in the promotion and tenure process

7. Calculating the IF The IF is calculated through a very specific formula: Cites to Recent Items / Number of Recent Items = Impact Factor (Recent Items = previous two years)

8. Criticisms of/Problems with the IF Validity: IF represents an arithmetic mean, rather than a normal distribution; some believe that this fact makes the IF unfit for assessing or evaluating relative impact of a journal. (Inter)disciplinarity: Journals indexed in Web of Science (and therefore JCR) are mainly science and social sciences journals; these disciplines mainly communicate through journal articles. Scholarship in the arts and humanities often appear in journals and books that are not part of Web of Science, which means that an IF cannot be calculated. This often causes confusion for interdisciplinary researchers. Editorial policies: Journals can (and do) manipulate their editorial policies so that they publish more review articles (more likely to be cited) or fewer “citable items” (which would raise their article/citation ratio). Self-cites: Some claim that authors’ self-cites can skew a journal’s impact factor.

9. How NOT to use the IF Do not use impact factors as the sole criteria for evaluating journals, individual papers, or specific researchers As you have gathered, impact factors may be a good indication of a journal’s value, but should not account for the total portrait of a journal’s value

10. Alternatives to the IF Although the Impact Factor remains the most frequently used number for assessing journals’ influence, several other similar calculations exist: H-Index: Focuses on assessing the work of a particular scholar; uses a formula that includes total output and citations for a specific researcher. Eigenfactor: Provides slightly different metrics from the impact factor; some believe it is more robust, since it takes into account the significance of citations. Often compared with the Google Page Rank system. SCImago Journal Rank: Provides journal rankings from the Scopus proprietary database (VT does not subscribe to this database) Google Scholar Citation Counter: Uses Google to search for a total number of citations for works indexed by Google Scholar; also relates the H-index

11. References & Further Reading Thomson (ISI) products useful in promotion and tenure, from Virginia Tech Libraries The Thomson Reuters Impact Factor, from Thomson Reuters The Agony and the Ecstasy—The History and Meaning of the Journal Impact Factor, by Eugene Garfield The Number that’s Devouring Science, from The Chronicle of Higher Education

12. Questions? Contact me! Rebecca K. Miller millerrk@vt.edu OR hnfelibrarian@vt.edu 5004 Newman Library Wallace Office Hours (Tuesdays/Wednesdays) http://hnfelibrarian.blogspot.com