9 November 2012: The modified sharpened index h(ms) and other variants in the Hirsch index zoo. Seminar presentation by Prof. Michael Schreiber
Is there a more appropriate way to estimate the visibility of a scientist’s research than the h-index?
The Hirsch index or h -index is widely used to quantify the impact of an individual’s scientific research output. Prof. Schreiber presents an analysis of two case studies, one for 8 famous physicists and another for 26 not-so-prominent colleagues. Difficulties with the determination of the index and its interpretation are discussed.
Fractionalised counting of the publications (rather than the citations) is an appropriate way to distribute the impact of a paper among all the coauthors of a multi-authored manuscript, leading to a simple modification h m of the h -index. On the other hand the exclusion of self-citations allows one to sharpen the index (yielding h s ), what is appropriate, because self-citations are usually not reflecting the significance of a publication. Combining the two procedures gives the modified sharpened index h ms .
The additional effort in determining the modified sharpened index h ms is worth performing in order to obtain a fairer evaluation of the citation records In order to take into account the highly skewed frequency distribution of citations, Egghe proposed the g -index as an improvement of the h -index. The g -index discriminates better between different citation patterns. Fractionalised counting of the multi-authored manuscripts leads again to a simple modification g m .
The exclusion of self-citations allows one to sharpen the index yielding g s .
In Prof. Schreiber's opinion the modified sharpened index g ms is the most appropriate way to estimate the visibility of a scientist’s research. Whether this is a measure of importance and significance is a debatable and debated question.
Therefore, as an alternative, percentile-based indicators have attracted more attention recently. Topical developments like the fractional scoring are presented and applied for two different case studies with empirical data.
Michael Schreiber is professor in theoretical physics at Chemnitz University of Technology. Apart from his physics research, he is also doing research in the area of bibliometrics. Most of his bibliometrics research has focused on the h-index and its variants. Michael Schreiber is editor-in-chief of the physics letter journal EPL, previously known as Europhysics Letters.
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