Authors:Ludo Waltman, Nees Jan van Eck, Thed N. van Leeuwen, Martijn S. Visser, and Anthony F. J. van Raan
make a more general remark on the comparison of citationanalysis and peer review.
The analysis of Van Raan ( 2006 ) is based on an assessment study of Dutch chemistry and chemical engineering research groups conducted
The h-index has received an enormous attention for being an indicator that measures the quality of researchers and organizations. We investigate to what degree authors can inflate their h-index through strategic self-citations with the help of a simulation. We extended Burrell's publication model with a procedure for placing self-citations, following three different strategies: random self-citation, recent self-citations and h-manipulating self-citations. The results show that authors can considerably inflate their h-index through self-citations. We propose the q-index as an indicator for how strategically an author has placed self-citations, and which serves as a tool to detect possible manipulation of the h-index. The results also show that the best strategy for an high h-index is publishing papers that are highly cited by others. The productivity has also a positive effect on the h-index.
Budapest, Leiden, Leuven, Beijing, Shanghai, etc.) or as independent commercial enterprises (e.g., Science-Metrix in Montreal). Two major companies (Thomson Reuters and Elsevier) are also active in this market. In other words, citationanalysis has become
Authors:Rodrigo Costas, Thed van Leeuwen, and María Bordons
This paper focuses on the study of self-citations at the meso and micro (individual) levels, on the basis of an analysis of
the production (1994–2004) of individual researchers working at the Spanish CSIC in the areas of Biology and Biomedicine and
Material Sciences. Two different types of self-citations are described: author self-citations (citations received from the
author him/herself) and co-author self-citations (citations received from the researchers’ co-authors but without his/her
participation). Self-citations do not play a decisive role in the high citation scores of documents either at the individual
or at the meso level, which are mainly due to external citations. At micro-level, the percentage of self-citations does not
change by professional rank or age, but differences in the relative weight of author and co-author self-citations have been
found. The percentage of co-author self-citations tends to decrease with age and professional rank while the percentage of
author self-citations shows the opposite trend. Suppressing author self-citations from citation counts to prevent overblown
self-citation practices may result in a higher reduction of citation numbers of old scientists and, particularly, of those
in the highest categories. Author and co-author self-citations provide valuable information on the scientific communication
process, but external citations are the most relevant for evaluative purposes. As a final recommendation, studies considering
self-citations at the individual level should make clear whether author or total self-citations are used as these can affect
) opened this discussion by asking whether citationanalysis enables us to legitimate the strategic selection of “excellent” as against merely “good” research?
The software for measuring this indicator is available at
). The use of bibliometric indicators is of course not without its critics and MacRoberts and MacRoberts ( 1996 ) highlighted some of the conceptual problems of citationanalysis.
One of the critical issues of a bibliometric analysis is the choice