REFLECTIONS ON THE H-INDEX

Since Hirsch’s first publication of the h-index in 2005 (Hirsch, 2005), this new measure of academic impact has generated a widespread interest. At the time of writing (January 2007) Google Scholar lists 50 citations to this paper and the subsequent publication in the Proceedings of the National Academy of Sciences. The h-index is defined as follows: A scientist has index h if h of his/her Np papers have at least h citations each, and the other (Np-h) papers have no more than h citations each. It aims to measure the cumulative impact of a researcher’s output by looking at the amount of citations his/her work has received. Hirsch argues that the hindex is preferable to other single-number criteria, such as the total number of papers, the total number of citations and citations per paper. However, Hirsch provides a strong caveat: Obviously a single number can never give more than a rough approximation to an individual’s multifaceted profile, and many other factors should be considered in combination in evaluating an individual. This and the fact that there can always be exceptions to rules should be kept in mind especially in life-changing decision such as the granting or denying of tenure. The advantage of the h-index is that it combines an assessment of both quantity (number of papers) and quality (impact, or citations to these papers) (Glänzel, 2006). An academic cannot have a high h-index without publishing a substantial number of papers. However, this is not enough. These papers need to be cited by other academics in order to count for the h-index.