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The h-index is an index suggested in 2005 by Jorge E. Hirsch of the University of California, San Diego to quantify the scientific productivity of physicists and other scientists based on their publication record.

Contents 1 Definition and Purpose 1.1 Criticism 2 Scientists in other fields with high h-indices 3 See also 4 References

[edit] Definition and Purpose

The index is calculated based on the distribution of citations received by a given researcher's publications. Hirsch writes:

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 at most h citations each.

In other words, a scholar with an index of h has published h papers with at least h citations each.[1] Thus, the H-index is the result of the balance between the number of publications and the number of citations per publication. The index is designed to improve upon simpler measures such as the total number of citations or publications, to distinguish truly influential scientists from those who simply publish many papers. The index is also not affected by single papers that have many citations. The index works properly only for comparing scientists working in the same field; citation conventions differ widely among different fields.

Online web programs are available to directly calculate a scientist's H-index number. The H-index can also be manually determined using free Internet databases, such as Google Scholar, and serves as an alternative to more traditional journal impact factor metrics, which are not freely available. Because only the most highly cited articles contribute to the h-index, its determination is a relatively simpler process. Hirsch has demonstrated that has high predictive value for whether or not a scientist has won honors like National Academy membership or the Nobel Prize. In physics, a moderately productive scientist should have an equal to the number of years of service while biomedical scientists tend to have higher values.

[edit] Criticism

It is not difficult to come up with situations in which may provide misleading information about a scientist's output. Most importantly the fact that is bounded by the total number of publications means that scientists with a short career are at an inherent disadvantage, regardless of the importance of their discoveries. For example, Evariste Galois' h-index is 2, and will remain so forever. Had Albert Einstein died in early 1906, his index would be stuck at 4 or 5, despite his being widely acknowledged as one of the most important physicists, even considering only his publications to that date.

Additionally, some potential drawbacks of the impact factor apply equally to the h-index. For example, review articles are usually more cited than original articles, so a hypothetic author who would only write review articles would have a higher h-index than authors who would actually contribute original research.

Proposals to modify the h-index in order to emphasize different features have been made [2].

[edit] Scientists in other fields with high h-indices

• Endel Tulving: h = 64 (Cognitive psychologist)

[edit] See also

• Bibliometrics
• A Rational Indicator of Scientific Creativity
• Erdős number
• A simple web script to compute a (raw) h-index based on Google Scholar
• The H-index for computer science
• A MATLAB script to compute the h-index
• h-b index
• Publish or Perish calculates various statistics, including the h-index and the g-index using Google Scholar data

[edit] References

• Hirsch, Jorge E., (2005), "An index to quantify an individual's scientific research output". Retrieved from arXiv February 13, 2006.
• Sidiropoulos A., Katsaros D. and Manolopoulos Y., (2006), Generalized h-index for disclosing latent facts in citation networks.
• Kelly C. D. and Jennions M.D. (2006), The h index and career assessment by numbers: a paper expounding certain problems of the h-index.
• "Impact factor," Science 309:1181, 19 August 2005.
• "An index to quantify an individual's scientific research output," PNAS 102(46):16569-16572, November 15 2005.
• H values for Stanford p-chem professors from "The Everyday Scientist"cs:Hirschův indexru:H-индекс

sl:H-indeks

This page uses content from the English-language version of Wikipedia. The original article was at Hirsch number. The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.