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

In this paper, empirical data are analysed to show some of the problems inv olved in the use of the Institute for Scientific Information's (ISI) impact factors (IFs). Based on earlier work of the authors, and elaborating on so me 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 lev els) to evaluate research performance, and librarians to evaluate their jou rnal collections, Whereas earlier papers have focused on problems involved with the definitions of the constituting elements of the classical IF and t he resulting errors, this paper focuses on the problems related to other ch aracteristics of scientific journals; in particular, the influence of the d istribution of papers among document types in a journal, the effects of spl itting of journals or changing their names, the measurement of (un)citednes s of papers in a journal, and the chosen length of the citation window with in the definition of the classical IF. This will raise the fundamental ques tion of whether an indicator, based on only a one- to two-year citation win dow, will be sufficiently valid to be of any use in analyses of journal and research performance.