Journal Impact Factor and H-index

1. Journal Impact Factorand H-index FarrokhHabibzadeh, MD, Secretary, World Association of Medical Editors (WAME) Editorial Consultant, The Lancet Vice President, Eastern Mediterranean Association of Medical Editors (EMAME) Director, NIOC Medical Education and Research Center, Shiraz, Iran

2. Scientometrics

3. Scientometrics (Definition) • Scientometrics is the science of measuring and analyzing science. • It is often done through bibliometrics.

4. Scientometrics • First citation analysis by Gross & Gross (1927) • Journal to journal cross-citation (Cason & Lubotsky, 1936) • Journal Impact Factor (IF) by Eugene Garfield (1955)

5. Journal Impact Factor

6. Journal Impact Factor • Definition: • IF: IF of journal in 2008 • P:number of substantive articles published in 2006-07 • C: number of citations made in year 2008 to articles published in 2006-07 • Garfield E. JAMA;295(1); 90-3

7. Example

8. Top Journals in General/Internal Medicine

9. Journal Impact Factor • Is calculated and sold by Thomson-Reuter (formerly Thomson Scientific, before that, the Institute of Scientific Information [ISI]) • No one has independently audited the validity of the data* • In many centers, affects • Decision on where to publish • Whom to promote or hire • Success of grant applications • Winning prize • Even salary bonuses *Rossner M, van Epps H, Hills E. J Exp Med 2007;204:3052-3

11. Journal Impact Factor • Pros • A measure for journal quality • Easy to calculate • Cons • Substantive articles? • May be used unwisely • “drawing conclusions about individual performance is not the proper way to interpret impact factor.”* • Calculations behind the wall† • Subject to manipulation‡ *http://scientific.thomsonreuters.com/citationimpactforum/8424440/ † Rossner M, van Epps H, Hills E. J Exp Med 2007;204:3052-3. ‡ Marusic A, et al. Science and Engineering Ethics 2008;14:41-9.

12. H-index

13. H-index • A scientist has index h, if h of his/her Np papers have at least h citations each, and the other (Np − h)papers have no more than h citations each. Hirsch JE.Proc Nat Acad Sci 2005;102:16569–72.

14. Example Number of Citations Paper

18. H-index • Pros • Two-dimensional • Cons • Who? • Different databases! • Contribution through one or two influential papers • Nikolai Korotkoff • Wilhelm Conrad Röntgen • Subject to manipulation • Self-citation • Member of a prolific research group 4 6

19. Alternatives

20. Journal Network

21. Weighted Impact Factor • Counting a reference from a more prestigious journal more heavily • Kochen, 1974 • Pinski & Narin, 1976 • PageRank of Google™ • Y-factor (Bollen, et al, 2006) • SCImago SJR (www.scimagojr.com, 2007) • Prestige: “the standing or estimation in the eyes of other people”/journals (Merriam-Webster Dictionary)

23. Journal Impact Factor • Definition: • IF: IF of journal in 2006 • P:number of substantive articles published in 2004-05 • C: number of citations made in year 2006 to articles published in 2004-05 • Garfield E. JAMA;295(1); 90-3

24. Weighted Impact Factor

25. Calculation of Weights • Popularity of the cited journal • Prestige of the citing relative to the cited journal

26. Calculation of Weights 1 q w [0, +)  [0.1, 10) 1 PYIF: Previous year IF

27. How Journals Are Cited IFWIF 1.346 2.703 1.333 3.723 14.780 7.410 23.175 8.869 51.296 14.472 13.750 14.475

28. Parameters of 70 Medical Journals

30. Other Metrics Jevin West Ben Althouse • Immediacy Index • Eigenfactor™ score • Article Influence™ score • Per article citation influence Martin Rosvall Carl Bergstrom Ted Bergstrom

31. Top Journals in General/Internal Medicine

32. None of these metrics are adequate compared with what should be the gold standard Peer Review

33. F1000 Medicine http://f1000medicine.com

35. Read the Articles; Don’t Count Them