Critical comments on Institute for Scientific Information impact factors: a sample of inorganic molecular chemistry journals

Abstract

In this paper, empirical data are analysed to show some of the problems involved in the use of the Institute for Scientific Information’s (ISI) impact factors (IFs). Based on earlier work of the authors, and elaborating on some new topics, the paper shows that IFs as defined by ISI have shortcomings which make them inappropriate for the purposes for which people use them: researchers for their publication strategy, policy makers (at different levels) to evaluate research performance, and librarians to evaluate their journal collections. Whereas earlier papers have focused on problems involved with the definitions of the constituting elements of the classical IF and the resulting errors, this paper focuses on the problems related to other characteristics of scientific journals; in particular, the influence of the distribution of papers among document types in a journal, the effects of splitting of journals or changing their names, the measurement of (un)citedness of papers in a journal, and the chosen length of the citation window within the definition of the classical IF. This will raise the fundamental question of whether an indicator, based on only a one- to two-year citation window, will be sufficiently valid to be of any use in analyses of journal and research performance.