Now you see it, now you don't: the strange world of disappearing Special Issues at MDPI

 

There is growing awareness that Special Issues have become a menace in the world of academic publishing, because they provide a convenient way for large volumes of low quality work to be published in journals that profit from a healthy article processing charge. There has been a consequent backlash against Special Issues, with various attempts to rein them in. Here I'll describe the backstory and show how such attempts are being subverted. 

Basically, when it became normative for journals to publish open access papers in exchange for an article processing charge, many publishers saw an opportunity to grow their business by expanding the number of articles they published. There was one snag: to maintain quality standards, one requires academic editors to oversee the peer review process and decide what to publish. The solution was to recruit large numbers of temporary "guest editors", each of whom could invite authors to submit to a Special Issue in their area of expertise; this cleverly solved two problems at once: it provided a way to increase the number of submissions to the journal, and it avoided overloading regular academic editors. In addition, if an eminent person could be persuaded to act as guest editor, this would encourage researchers to submit their work to a Special Issue.

Problems soon became apparent though. Dubious individuals, including those running paper mills, seized the opportunity to volunteer as guest editors, and then proceeded to fill Special Issues with papers that were at best low quality and at worse fraudulent. As described in this blogpost, the publisher Wiley, was badly hit by fallout from the Special Issues programme, with its Hindawi brand being 'sunsetted' in 2023 . In addition, the Swiss National Science Foundation declared they would not fund APCs for articles in Special Issues, on the grounds that the increase in the number of special issues was associated with shorter processing times and lower rejection rates, suggestive of rushed and superficial peer review. Other commentators noted the reputational risks of overreliance on Special Issues.

Some publishers that had adopted the same strategy for growth looked on nervously, but basically took the line that the golden goose should be tethered rather than killed, introducing various stringent conditions around how Special Issues operated. The publisher MDPI, one of those that had massive growth in Special Issues in recent years, issued detailed guidelines.

One of these concerned guest editors publishing in their own special issues. These guidelines have undergone subtle changes over time, as evidenced by these comparisons of different versions (accessed via Wayback Machine):

JUNE 2022: The special issue may publish contributions from the Guest Editor(s), but the number of such contributions should be limited to 20%, to ensure the diversity and inclusiveness of authorship representing the research area of the Special Issue.... Any article submitted by a Guest Editor will be handled by a member of the Editorial Board.

 21 JAN 2023: The special issue may publish contributions from the Guest Editor(s), but the number of such contributions should be limited, to ensure the diversity and inclusiveness of authorship representing the research area of the Special Issue. Any article submitted by a Guest Editor will be handled by a member of the Editorial Board.

2 JAN 2024: The special issue may publish contributions from the Guest Editor(s), but the number of such contributions should be limited to 25%, to ensure the diversity and inclusiveness of authorship representing the research area of the Special Issue. Any article submitted by a Guest Editor will be handled by a member of the Editorial Board.

3 MAY 2024: The special issue may publish contributions from the Guest Editor(s), but the number of such contributions should be limited, to ensure the diversity and inclusiveness of authorship representing the research area of the Special Issue. Any article submitted by a Guest Editor will be handled by a member of the Editorial Board.

The May 2024 version of guidelines is nonspecific but problematic, because it is out of alignment with criteria for accreditation by the Directory of Open Access Journals (DOAJ) , who state "Papers submitted to a special issue by the guest editor(s) must be handled under an independent review process and make up no more than 25% of the issue's total". Most of MDPI's journals are listed on DOAJ, which is a signal of trustworthiness.

So, how well is MDPI doing in terms of the DOAJ criteria? I was first prompted to ask this question when writing about an article in a Special Issue of Journal of Personalized Medicine that claimed to "reverse autism symptoms". You can read my critique of that article here; one question it raised was how on earth did it ever get published? I noted that the paper was handled by a guest editor, Richard E. Frye, who had coauthored 7 of the 14 articles in the Special Issue. I subsequently found that between 2021 and 2024 he had published 30 articles in Journal of Personalized Medicine, most in three special issues where he was guest editor. I'm pleased to say that DOAJ have now delisted the journal from their Directory. But this raises the question of how well MDPI is regulating their guest editors to prevent them going rogue and using a Special Issue as a repository for papers by themselves and their cronies.

To check up on this, I took a look at Special Issues published in 2023-2024 in 28 other MDPI journals*, focusing particularly on those with implications for public health. What I found was concerning at four levels. 

1. Every single journal I looked at had Special Issues that broke the DOAJ rule of no more than 25% papers co-authored by guest editors (something DOAJ refer to as "endogeny").  Some of these can be found on PubPeer, flagged with the term "stuffedSI". 
2. A minority of Special Issues conformed to the description of a "successful Special Issue" envisaged by the MDPI guidelines: "Normally, a successful Special Issue consists of 10 or more papers, in addition to an editorial (optional) written by the Guest Editor(s)." For the journals I looked at around 60% of Special Issues had fewer than 10 articles. 
3. Quite often, the listed guest editors did not actually do any editing. One can check this by comparing the Action Editor listed for each article. Here's one example, where a different editor was needed for three of the nine papers to avoid conflict of interest, because they were co-authored by the guest editors;  but the guest editors are not listed as action editors for any of the other six papers in the special issue. 
   
4. As I did this analysis, I became aware that some articles changed status. For instance, Richard E. Frye, mentioned above, had additional articles in the Journal of Personalized Medicine that were originally part of a Special Issue that are now listed as just belonging to a Section. see https://pubpeer.com/publications/BA21B22CA3FED62B6D3F679978F591#1.This change was not transparent, but was evident when earlier versions of the website were accessed using the Wayback Machine. Some of these are flagged with the term "stealth correction" on PubPeer.

This final observation was particularly worrying, because it indicated that the publisher could change the Special Issue status of articles post-publication. The concern is that lack of oversight of guest editors has created a mechanism whereby authors can propose a Special Issue, get taken on as a guest editor, and then have papers accepted there (either their own, or from friends, which could include papermillers), after which the Special Issue status is removed. In fact, given the growing nervousness around Special Issues, removal of Special Issue status could be an advantage.

When I have discussed with colleagues these and other issues around MDPI practices, I find that credible researchers tell me that there are some excellent journals published by MDPI. It seems unfortunate that, in seeking rapid growth via the mechanism of Special Issues, the publisher has risked its reputation by giving editorial responsibility to numerous guest editors without adequate oversight, and encouraged quantity over quality. Furthermore, the lack of transparency demonstrated by the publisher covertly removing Special Issue status from articles by guest editors does not appear consistent with their stated commitment to ethical policies. 

 *The code for this analysis and a summary chart for the 28 journals can be found on Github.