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Ranking of journals by journal impact factors is not exact and may provoke misleading conclusions
  1. Konradin Metze,
  2. Fernanda Aparecida Borges da Silva
  1. Department of Pathology Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
  1. Correspondence to Konradin Metze, State University of Campinas, Campinas, SP 13083-872, Brazil; kmetze{at}

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Every year in June or July, Clarivate publishes the journal citation reports of the year before. The most popular bibliometric parameter is the 2-year impact factor (JIF) which is used by researchers to decide where to publish and by scientific agencies or selection committees to evaluate scientists and journals. The 2-year JIF is usually highlighted on the journals’ home pages. Furthermore, Clarivate publishes rankings for specific scientific fields by ranking the journals by the JIF.1 This value is often highlighted in the advertising of a publisher with affirmations such as the rank of a certain journal has improved for instance from the 20th to the 15th rank. We want to show that these lists are pseudo-exact and may provoke misleading conclusions.

The JIF of 2020 calculates the mean of citations in all indexed papers published in 2020 to articles released in 2018 and 2019 by a specific journal. Therefore, it represents only a small part of all articles in this journal, that is, only a sample influenced by stochastic fluctuations. In this case, CIs could express the degree of uncertainty of the samples.2 Bornmann has already suggested to interpret JIFs together with their 95% CIs, which can …

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  • Handling editor Tahir S Pillay.

  • Contributors KM contributed to conceptualisation; data curation; formal analysis; investigation; methodology; project administration; supervision; validation; writing-original draft; writing-review & editing. FABdS contributed to conceptualisation; data curation; investigation; methodology.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.