Earlier this fall, Clarivate Analytics announced that it was moving toward a future that calculated the Journal Impact Factor (JIF) based on the date of electronic publication and not the date of print publication.
If your first reaction was “What took you so long!” you are not alone.
Online publication dates back to the mid 1990s, with several forward-looking journals hosting some or all of their content on this futuristic thingy known as the World Wide Web. By the early 2000s, titles like the Journal of Biological Chemistry had a robust model of publishing accepted peer-reviewed papers online before rushing them off through typesetting, layout, and print distribution. Today, two decades later, terms like “Publish-ahead-of-Print,” “Early Online,” “Early View” and their variants seem quaint and anachronistic as we all got accustomed to a model where electronic became the default model of journal publication. Still, Clarivate stuck to a model that based publication date on print. While the lag time between online publication and print designation is short for some titles, it can be months (or even years) for others. For most online-only journals, there is only one publication date.
This discrepancy between how Clarivate treated traditional print versus online-only journals aroused skepticism among scientists, some of whom argued that long delays between print and online publication benefited the JIF scores of traditional journals over newer open access titles, and cynically suggested that editors may be purposefully extending their lag in an attempt to artificially raise their scores. Whether or not this argument has merit (their methods for counting valid citations are problematic), lag times create problems in the citation record, especially when a paper has been published online in one calendar year and print in another — for example, published online in December 2019 but appearing in the January 2020 print issue. In this case, one author may cite the paper as being published in 2019; another in 2020. Clarivate will keep both variations of the reference but link only the latter in its Web of Science (WoS) index. This is just one reason why it’s so difficult to calculate accurate Impact Factor scores from the WoS. By adopting a new electronic publication standard, Clarivate will help reduce ambiguity in the citation record. It will also make it easier and more transparent to calculate citation metrics. So, what took them so long?
The Web of Science began including electronic (“Early Access”) publication dates in its records since 2017 and now includes this information for more than 6,000 journals, according to Dr. Nandita Quaderi, Editor-in-Chief of the WoS. While this number sounds impressive, we should note that it represents only about half of the 12,000+ journals they currently index. More journals will be added “using a phased, prospective approach to accommodate timing differences in publisher onboarding,” which makes it sound like the delay in implementation is in the hands of publishers and vendors who are coming late to the table. I asked for a list of titles or publishers included in the program and have not heard back, so I created my own list (
download spreadsheet link removed at request of Clarivate).
From this list, I counted 43,831 Early Access records from 4,991 sources in the WoS with a 2020 publication date. While I could identify titles published by Springer Nature, Wiley, and JAMA, conspicuously absent were titles from Elsevier (including Cell Press and Lancet), university presses (Oxford, Cambridge), together with publications from prominent societies and associations, like the American Association for the Advancement of Science, the American Chemical Society, the American Heart Association, and American Society for Microbiology, among others. Strangely, these publishers have been sending online publication metadata to PubMed for years.
The next 2021 release (using 2020 data) will be a transition year, in which citations from Early Access records will be added the numerator of the JIF calculation but excluded from publication counts in the denominator.
According to Seven Hubbard, Content Team Lead for the Journal Citation Reports (JCR), the full switch to using online publication for the calculation of Journal Impact Factors (JIFs) will begin in 2022 using 2021 publication data. The next 2021 release (using 2020 data) will be a transition year, in which citations from Early Access records will be added the numerator of the JIF calculation but excluded from publication counts in the denominator.
Adding possibly hundreds of thousands of citations to Clarivate’s calculations is expected to have an inflationary effect on the 2020 JIF scores of all journals that receive them. If we expect that these new Early Access papers are just like the papers that preceded them, they will distribute citations similarly across the network of interlinked journals. Like the ocean, the rising tide will lift all boats.
However, participating Early Access journals will receive an additional shot of self-citations, which may be sufficient to push their JIF scores above close competitors who are not currently in Clarivate’s phased implementation program. In other words, the tide will lift the journals of participating publishers much higher than non-participants. The inflationary effect to the calculation of the JIF will likely turn negative the following year as citations from these 2020 Early Access papers (published in print in 2021) are ignored for the 2021 JIF calculation.
Clarivate’s phased roll-out may preferentially benefit participating publishers, bias others
Given the potential of changing the ranking of journals, I asked Hubbard whether he or his team had tested whether adding Early Access citations changed the ranking of journals or whether it preferentially benefited participating publishers. At the time of this writing, I have not received a response.
The changes at Clarivate are welcome and long overdue. While it is not clear how a shift from print to online publication dates will affect the ranking of journals, it should help to reduce ambiguity and confusion in the citation record. A lack of transparency and communication on the anticipated effects of this transition are troubling however, especially because they currently involve just one-half of active journals. If arriving at a fair and unbiased assessment means waiting another year for all publishers to participate, I’m personally willing to wait.
Feb 1, 2021 Update: See estimates of JIF effect in Changing Journal Impact Factor Rules Creates Unfair Playing Field For Some.