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h-index explained

The h-index is a statistic designed to account for both the productivity and the impact of a scholar.

"A scientist has index h if h of his or her Np papers have at least h citations each and the other (Np - h) papers have ≤ h citations each," where Np is "the number of papers published over n years" (Hirsch, 2005).

The index h indicates that a researcher has published h articles that have been cited h or more times.


Hirsch, J. E. (2005). An Index to Quantify an Individual’s Scientific Research Output. Proceedings of the National Academy of Sciences of the United States of America, 102(46), 16569–16572. doi:10.2307/4152261 (Remote link)

Calculating h-index

To calculate the h-index, the scholar’s or journal’s articles are first ordered by the number of citations received, from most- to least-cited. Suppose a researcher has published 15 articles, cited the following number of times:

Article Times cited
1 115
2 20
3 18
4 12
5 7
6 7
7 4
8 4
9 4
10 3
11 2
12 2
13 1
14 0
15 0


This researcher has an h-index of 6, because six of his or her articles have received six or more citations, while the remaining nine have received fewer than six citations. Note that the mean number of citations received is considerably higher, 13.3, because of the effect of the one exceptionally influential article. The h-index is designed to reduce the weight of a small number of highly cited papers.

Finding h-index: Web of Science

  • Go to Web of Science
  • Change search type to Author Search.
  • Complete the search form. Enter the name (and name variants, if applicable), or ORCID iD of the author.
  • Your search may return results from multiple authors. Select only the one(s) that is your target author.
  • Summary statistics are provided in the Citation Network box at the upper right, including h-index.

Video: Web of Science Citation Report

Tags: bibliometrics