Metrics: Reflections on the 2020s impact factors

As soon as the new impact factors (IF) are released, we start receiving dozens of emails from the journals celebrating the rise in their specific IF. However, this year's global rise in IF is particularly surprising. In the 2020 edition, the average IF of the journals in the Science Edition of JCR has increased 25.1% as compared to 2019 (Figure 1), representing more than four times the average increase in the three previous years (6.2%). Noteworthy, the IF of the 25 top journals in the list has risen 34%. Since the number of journals has only increased 1.3% (slightly lower than precedent years) and the number of citable items remains more or less constant, it might be speculated that this is due to an increase in citations (equating 25.7%, similar to the average increase in the IF). Precisely, according to Clarivate's web page,1 this year's release introduces Early Access articles ‘reflecting the earliest availability of new research as it appears in the ‘version of record’ prior to official publication’. This represents a dramatic change that needs clarification regarding its application in further years since metrics are used worldwide in evaluation processes.2 As it is expected that the new advanced content taken into account for this year's calculations cannot be taken into account next year when it is published in its final version, it is possible that next year, we will see an unprecedented decrease in the journals’ IF.

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Mean ± SD of the impact factor of journals included in the Clarivate's Journal Citation Reports, Science Citation Index (SCI) edition (left y-axis) and the absolute number of journals (right y-axis) in the present edition (2020) and the previous 4 years

ACKNOWLEDGEMENTS

Supported by PI19/00785, PI20/00080, PI20/00927 and CIBEROBN, ISCIII, Spain.

CONFLICT OF INTEREST

No potential conflict of interest relevant to this commentary was reported.

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