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January 01, 2007

Calculating scholarly impact

Scholars and their employers have long wanted metrics for measuring the importance or impact of a scholar's research output. Citation counts have been used for years, often based on the citation indices published by ISI. Recently many have started doing citation counts using Google Scholar (GS). Judit Bar-Ilan wrote a scholarly article comparing ISI, GS and Citeseer.

Recently, there have been various attempts to create metrics that are more informative than merely counting citations. The current favorite seems to be the h-index, suggested in 2005 by Jorge E. Hirsch at the University of California, San Diego (An index to quantify an individual's scientific research output, arXiv:physics/0508025 v5 29 Sep 2005). The Wikipedia article has a good summary. Two others are the g-index (Leo Egghe, Theory and practice of the g-index, Scientometrics, Vol. 69, No 1 (2006), pp. 131-152) which gives more weight to highly cited articles, and the contemporary h-index (Antonis Sidiropoulos, Dimitrios Katsarow, and Yannis Manolopoulos in their paper Generalized h-index for disclosing latent facts in citation networks, arXiv:cs.DL/0607066 v1 13 Jul 2006), which is parameterized to weight recent articles more heavily.

Here is a web based h-index calculator (using citations from GS as its database). Note that any calculation is subject to error if the scholar's name is not unique; this tool provides a boolean keyword restrictor that offers an attempt to ameliorate this problem. And here you can download a software tool that calculates h-index, g-index and others. This tool reports all of the articles used for the count, so you can check to eliminate those by different authors.

Using both of these tools, my h-index is 24 (although two articles with 24 cites also appear with 1 more cite to a listing with a typo in the title: when combined, my h-index is 25, a small example of the errors automatic tools can make).

Posted by jmm at January 1, 2007 03:12 PM