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Quantitative evaluation of citation data to support funding decisions has become widespread. For this purpose there exist many measures (indices) and while their properties were well studied there is little comprehensive experimental comparison of the ranking lists obtained when using different methods. A further problem of the existing studies is that lack of available data about net citations prevents researchers from studying the effect of measuring scientific impact by using net citations (all citations minus self-citations). In this paper we use simulated data to study factors that could potentially influence the degree of agreement between the rankings obtained when using different indices with the emphasis given to the comparison of the number of net citations per author to other more established indices. We observe that the researchers publishing papers with a large number of co-authors are systematically ranked higher when using h-index or total citations (TC) instead of the number of citations per author (TCA), that the researchers who publish a small proportion of papers which receive many citations while the rest of their papers receive only few citations are systematically ranked higher when using TCA or TC instead of h-index, and that the authors who have lower proportion of self-citations are ranked higher when considering indices which include the number of net citations in comparison with indices considering only the total citation count. Results are verified and illustrated also by analyzing a large dataset from the field of medical science in Slovenia for the period 1986---2007.

The Table 1 (EU declaration signatory and membership status) of the original article published online contained several errors: the IARC was incorrectly listed in the table, which only includes countries, and footnote; Croatia, Lithuania, Poland and Portugal were not listed as full EMBL members; Estonia is now listed as a Prospect Member of EMBL; Hungary, Ireland and Israel were incorrectly listed as BBMRI-ERIC members; Iceland was omitted from the table. Hyphens stand for ‘not applicable’; the table and footnote have been corrected accordingly. These errors have now been corrected online and in print.