Validation of Journal Impact Metrics of Web of Science and Scopus

Citation based metrics are widely used to assess the impact of research published in journals. This paper presents the results of a research study to verify the accuracy of data and calculations of journal impact metrics presented in Web of Science (WoS) and Scopus in the case of three journals of information and library science. Data collected from the websites of journals were compared with that of two citation extended databases. The study manually calculated the Journal Impact Factor (JIF) and the Impact per Publication (IPP) in accordance with formulas given in the databases. Data were also collected from the Google Scholar to draw a comparison. The study found discrepancies in two sets of data and bibliometric values, i.e., systematic values presented in WoS and Scopus and calculated in this study. Commercial databases presented inflated measures based on fabricated or erroneous data. The study is of practical importance to researchers, universities and research financing bodies that consider these bibliometric indicators as a good tool for measuring performance, assessment, and evaluation of research quality as well as researchers.