Scientometrics (Definition)

Transcription

1 Farrokh Habibzadeh, MD, Vice President, World Association of Medical Editors (WAME) Honorary Editor, The Lancet ME Editorial Consultant, The Lancet Founding Editor, The IJOEM Director, NIOC Medical Education and Research Center, Shiraz, Iran 1

2 Scientometrics (Definition) Scientometrics is the science of measuring and analyzing science. It is often done through bibliometrics. Scientometrics First citation analysis by Gross & Gross (1927) Journal to journal cross citation (Cason & Lubotsky, 1936) Journal Impact Factor (IF) by J p ( ) y Eugene Garfield (1955) 2

3 Journal Impact Factor Definition: C IF = P IF: IF of journal in 2006 IF i = n k= 1 C P i ki, P:number of substantive articles published in C: number of citations made in year 2006 to articles published in Garfield E. JAMA 2006;295;

4 Example Top Journals in Cardiology 4

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

6 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 p way to interpret impact factor. * Calculations behind the wall Subject to manipulation * Rossner M, et al. J Exp Med 2007;204: Marusic A, et al. Science and Engineering Ethics 2008;14:

7 Citations to Am J Cardiol Impact Factor 2009: SEARCH STRATEGY Database: Web of Knowledge (ISI) Publication Name=(American Journal of Cardiology) AND Year Published=(2009) Refined by: Document Type=(ARTICLE OR REVIEW) RESULTS 1889 records 946 articles and reviews Minimum: 0; Maximum: 60 Mean (SD): 3.3 (5.1); Median (IQR): 2 (5) Skewness: 3.7 Distribution of Citations 7

8 Citations to Articles in 2009 SEARCH STRATEGY Database: Web of Knowledge (ISI) Address=(Shiraz) AND Address=(Iran) AND Year Published=(2009) Refined by: Subject Areas=(CARDIOVASCULAR SYSTEM & CARDIOLOGY) AND Document Type=(ARTICLE) RESULTS Total Cardiovascular 56 Articles Distribution of Citations 8

9 H index A scientist has index h, if h of his/her N p papers have at least h citations each, and the other (N p h) papers have no more than h citations each. Hirsch JE. Proc Nat Acad Sci 2005;102:

10 H index = 5 H index = 3 10

11 H index = 7 11

12 H index = 6 H index Pros Two dimensional Cons Who? Different databases! Contribution ti through h one or two influential l papers Nikolai Korotkoff Wilhelm Conrad Röntgen Subject to manipulation Self citation Member of a prolific research group 12

13 H index and its variants Bornmann L, et al. J Am Soc Info Sci Technol 2008;59: Article No Citations Author 1 Author Total Zhang CT. PLoS ONE 4(5): e5429. doi: /journal.pone

14 Journal Network 14

15 Weighted Impact Factor Counting a reference from a more prestigious i journal more heavily Kochen, 1974 Pinski & Narin, 1976 PageRank of Google Y factor (Bollen, et al, 2006) SCImago SJR ( 2007) Prestige: the standing or estimation in the eyes of other people /journals (Merriam Webster Dictionary) 15

16 Top Journals in Cardiology 16

17 SJR vs JIF Sicilia MA, et al. J Informetrics 2011; doi: /j.joi

18 Journal Impact Factor Definition: C IF = P IF: IF of journal in 2006 IF i = n k= 1 C P i ki, P:number of substantive articles published in C: number of citations made in year 2006 to articles published in Garfield E. JAMA 2006;295;

19 Weighted Impact Factor WIF i = n k= 1 w ki, ki, P i C Calculation of Weights Popularity of the cited journal Prestige of the citing relative to the cited journal 19

20 Calculation of Weights q w [0, + ) [0.1, 10) w ki, q ki, weight 8.00 PYIFk = PYIF 6.00 i 4.00 q, e ki = qki, e quotient PYIF: Previous year IF How Journals Are Cited IF WIF SWISS MED WKLY J TRAVEL MED ANN INTERN MED JAMA J AM MED ASSOC NEW ENGL J MED IF < PLOS MED >5 0% 20% 40% 60% 80% 100% Percentage of Citations 20

21 Parameters of 70 Medical Journals Rank Articles Published in Total Cites Received in Year 2006 IF WIF Abbreviated Journal Title IF WIF 1 2 NEW ENGL J MED , LANCET , JAMA J AM MED ASSOC , ANN INTERN MED 364 5, PLOS MED 108 1, ANNU REV MED BRIT MED J 910 8, ANN FAM MED AMYLOID J AM BOARD FAM MED SWISS MED WKLY J TRAVEL MED DM DIS MON CAN FAM PHYSICIAN Weighted Impact Factor (WIF) 10 1 AMYLOID PLOS MED ANNU REV MED ANN INTERN MED LANCET NEW ENGL J MED JAMA-J AM MED ASSOC DM-DIS MON WIF = 0.28 IF Spearman's rho = 0.78, n = Impact Factor (IF) 21

22 Other Metrics Eigenfactor score Article Influence score Per article citation influence Jevin West Ben Althouse Martin Rosvall Carl Bergstrom Ted Bergstrom Top Journals in Cardiology 22

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24 F1000 Medicine 24