The H-Index: The Hot Topic in Information Science

Data from Thomson Scientific’s Essential Science Indicators, 2005-07

March 13, 2008

 Paper%3Cbr /%3EAuthor(s), JournalCitations
1An index to quantify an individual’s scientific research output J. E. Hirsch, PNAS: Proceedings of the National Academy of Sciences of the United States of America,02 (46): 16569-16572 15 Nov 200570
2Does the h-index for ranking of scientists really work%3F L. Bornmann and H. D. Daniel, Scientometrics 65 (3): 391-392 Dec 200522
3Comparison of the Hirsch-index with standard bibliometric indicators and with peer judgment for 147 chemistry research groups A. F. J. Van Raan, Scientometrics 67 (3): 491-502 June 200614
4On the h-index – a mathematical approach to a new measure of publication activity and citation impact W. Glanzel, Scientometrics 67 (2): 315-321 May 200612
5Using the h-index to rank influential information scientists B. Cronin and L. Meho, Journal of the American Society for Information Science and Technology 57 (9): 15-18 July 200611
6Is it possible to compare researchers with different scientific interests%3F P. D. Batista, M. G. Campiteli, O. Kinouchi and A. S. Martinez Scientometrics 68 (1): 179-189 July 200611
7An informetric model for the Hirsch-index, L. Egghe and R. Rousseau, Scientometrics 69 (1): 121-129 April 200610
8What do we know about the h index%3F L. Bornmann and H. D. Daniel, Journal of the American Society for Information Science and Technology 58 (9): 1381-1385 July 20073
In late 2005, Jorge E. Hirsch, professor of physics at the University of California, San Diego, published an article describing the h-index, which he called “a useful index to characterise the scientific output of a researcher”. This paper (which can be viewed at has been cited 90 times as of this writing. A survey of the current edition of Thomson Scientific’s Essential Science Indicators database reveals that the h-index is the hottest topic in information science today. The same database lists a Research Front, derived from co-citation analysis, with eight core papers (see left), including that by Professor Hirsch, that have collectively attracted more than 150 citations. Professor Hirsch himself recently published another paper on this subject: “Does the h-index have predictive power?,” PNAS, 104(49): 19193-8, 26 November 2007. Professor Hirsch describes the h-index thus: “A scientist has an index h if h of his or her Np papers have at least h citations each and the other (Np – h) papers have less than or equal to h citations each.” Np is the number of papers published over n years. Professor Hirsch found that among the physicists he surveyed, Edward Witten – a mathematical physicist at the Institute for Advanced Study in Princeton, New Jersey, and a pioneer in string theory and related areas – had the highest h-index: 110. “That is,” he explained, “Witten has written 110 papers with at least 110 citations each.” Professor Hirsch argued that “h is preferable to other single-number criteria commonly used to evaluate scientific output of a researcher”, and he listed total papers, total citations, citation per paper, number of significant papers (defined as the number of papers with more than a certain number of citations), and number of citations to each of a researcher’s q most cited papers (for example, q = 5).

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