In this space last year, I provided some explanation of the Journal Impact Factor (JIF), the journal metric released annually by Clarivate Analytics as part of the Journal Citation Reports (JCR). This year provides an opportunity to address the changes that Clarivate have imposed over the past three years and how macrotrends in scientific publishing have affected journal metrics.
From 1975 to 2019, the JIF was calculated using the same data definitions and formula. The great advantage of this consistency was that it enabled every journal to make relatively accurate year-to-year comparisons, and easily identify the variables that may have driven the JIF up or down. Consequently, editorial strategies were easier to develop and assess.
2020 Journal Impact Factor: Introducing “Early Access”
This all came to a somewhat crashing halt with the release of the 2020 JIFs. As communicated by Clarivate, the 2020 JIF would see the introduction of “Early Access” content to the JIF formula, though 2020 would be a transition year. “Early Access” content, a finalized version of an article not yet published in an issue, could now be indexed in Web of Science and contribute to the JIF formula. Complicating this was that a small subset of journals and publishers had participated in a two-year trial prior to 2020. Clarivate had to come up with a way to accommodate the citations that had been generated by “Early Access” content without giving journals that had participated in the pilot an unprecedented advantage.
The 2020 JIF formula would include citations from “Early Access” content in the numerators of any journals whose content has been cited during the pilot, but would not include “Early Access” content in the denominator of journals that published “Early Access” until the articles had appeared in an issue. There was an enormous amount of debate at the time over how this would skew JIF rankings, and to what extent this was to the advantage of journals that published both “Early Access” content and exhibited a relatively high rate of self-citation. Most publishers anticipated that that 2020 JIFs would experience some level of inflation, solely due to the introduction of “Early Access” content into the pipeline of citations.
Instead, any affect the “Early Access” content had on JIFs was completely overwhelmed by the far more extensive impact of a boom in published research that was driven directly and indirectly by COVID-19. Scientific output increased across all specialties in 2020, and the more articles being published, the more citations are being entered into the scientific literature. For editors, it was a rollercoaster ride of excitement when the journals’ 2020 JIF was 20% higher than 2019, and then the realization that this same growth had occurred for all competing journals as well. For most journals, regardless of the improvement in JIF, their rankings remained largely the same.
2021 Journal Impact Factor: Outliers Abound
The 2021 JIF ended the “Early Access” transition period, and “Early Access” content was now fully incorporated into the JIF formula. Again, there was an expectation from publishers that the JIFs would now largely normalize; however, COVID-19 was still having a tremendous impact on the publishing landscape. Although overall output had begun to slow by the end of 2021, citation activity remained high, and on average we saw JIF remain static. However, in some subjects, citation outliers drove some journal JIFs into a second wave of growth. Analysis revealed that COVID-related review articles with straightforward titles, such as “COVID and Pregnancy” or “Coronavirus and Hypertension” received citations far above average. In some cases, one of these articles alone could drive the Impact Factor 15%-20% higher.
2022 Journal Impact Factors: The End of the COVID Bump and Welcome ESCI Journals
If 2020 and 2021 JIFs had been inflated by the unusually high publication outputs in those years, the 2022 JIF represented a reset of sorts. JIFs returned to their 2019 numbers driven down by two primary factors: First, as scientific output decreased, the number of citations in the pipeline decreased and numerators dropped, and second, the increased output of both 2020 and 2021 were now being reflected for the first time in the denominator. Across the Wolters Kluwer (ACSM's publishing partner) portfolio, JIFs fell by an average of 7.3% (0.43 lower) than 2021 JIFs. If there was any concern that this was limited to Wolters Kluwer, it’s important to note that average rankings rose slightly by 0.1 place. We can assume that this means that the JIF deflation affected almost every publisher across every category.
Confusing comparison to JIFs of years past, the 2022 JIFs also were displayed to only one decimal place (as opposed to the three previously displayed). Since JIFs were rounded to the nearest tenth, it means that the differences in JIF from 2021 to 2022 could have a margin of error of 0.054. Also, this new change in JIF precision almost certainly will result in the introduction of ties moving forward – changing the methodology by which Clarivate will determine category rankings.
Significantly, Clarivate also awarded journals that had been indexed in the Emerging Sources Citation Index (ESCI) JIFs for the first time. In total, this means that almost 9,000 journals will be receiving a JIF for the first time (8% more open access journals, and 5% more journals from south of the equator). However, ESCI journals will not receive category rankings in the 2022 JCR.
2023 Journal Impact Factors: About Those Rankings
In next year’s JCR, all the different database rankings (ESCI, SCIE, and SSCI) will be combined into unified categories. In the past, for example, a nursing journal might be in both SCIE and SSCI, receiving a single JIF, but two distinct rankings for each database. Another nursing journal may have been in ESCI, receiving a JIF, but no ranking. In 2023, there will be a single set of rankings for each category, regardless of the database(s) in which the journal is indexed. The addition of ESCI journals may have a significant impact on which quartile SCIE-indexed journals may find themselves. It also begs the question of why ESCI continues to exist as a separate database.
Optimistically, I hope that the 2023 JCR reflects the last changes we will see to how JIF is both calculated and displayed for the near future – but I suspect that Clarivate may have opened a Pandora’s box of complications, which will be marked by a series of adjustments and overcorrections. In Clarivate’s own words, they have made some of these changes to de-emphasize the JIF, and force journals to consider other metrics, such as the Journal Citation Indicator (JCI). It remains to be seen if journals themselves will become so exasperated by Clarivate’s changes to the JIF that we will finally begin to discuss a journal’s Eigenfactor Score – in my opinion, the best journal metric ever devised!
Duncan MacRae is the director, Editorial Strategy and Publishing Policy for Wolters Kluwer, one of the world’s foremost publishers of medical, nursing and allied health journals. In this role, Duncan oversees the development and implementation of editorial policies followed by journals in the Lippincott and Medknow imprints. In addition, he works with a portfolio of editorial service providers to assist our society partners in achieving their strategic goals.