The practice of publishing a journal article online and then post-dating its official release several months later as it is slotted into a print issue is not uncommon. This practice, however, can be manipulated into increasing a journal’s impact factor, argues Frank Krell in a new article published — online, one month in advance — in the April issue of Learned Publishing.
In his article, “Academic publishers’ time-loop: another mechanism to manipulate impact factors?“ Krell argues that post-dating publication dates buys an article more time to be cited, and that the effect is greatest when articles, published online at the end of one year (e.g., December, 2011), are post-dated to appear in the first issue of the next year (e.g., January, 2012). In these cases, the contribution of article citations toward the journal’s impact factor are shifted ahead by one year (e.g., from 2012-2013 to 2013-2014). He writes:
Whether this effect is intended by publishers, or just tolerated, it is likely to increase Journal Impact Factors. At any rate, even if not all journals are affected considerably, the publication date should be the date of the actual publication, not a meaningless clerical tool that can be used at will to influence citation metrics.
While Krell’s position is sound, it is based on personal anecdote. According to Marie McVeigh, Director of the Journal Citation Report (JCR) and Bibliographic Policy for Thomson Reuters, “We have no data to suggest that manipulating publication dates is influencing JCR metrics.”
It’s very difficult to predict the citation pattern for an individual article, explained McVeigh. Shifting the window of observation one year forward or one year back can backfire. “It can be like robbing Peter to pay Paul.”
While many science journals use a first-in/first-out production schedule, editors can adjust the publication date of articles for various reasons, such as in the compilation of special issues or because there is reason to publish two or more related articles in a given issue. Editors will also time the release of articles to closely follow a conference presentation, or for various related reasons, none of them having to do with their impact factor.
To me, there needs to be some evidence — even anecdotal — that editors are purposefully post-dating publication for the purposes of citation gaming. Large January issues may be one piece of evidence; however, it may also signal the funding and publication cycle of academics. I’d be more interested to know whether post-dating conversations are going on within editorial boards, or whether authors have been told that the editor is holding back their article to maximize its contribution to the journal’s impact factor.
Editors may be playing their own version of “The Post-Dating Game,” but without more evidence, Krell’s claim should be considered a conjecture.