MDPI’s special issue explosion is a disgrace to science
The world’s biggest Open Access provider has recently overflooded the market using a publishing strategy that looks more like a “money machine fraud operation”.
In 2021, MDPI published about 40 000 so-called special issues, which is approximately one unique issue released every fifteenth minute, including weekends. It makes you wonder how exclusive these article series really are when virtually a majority of what is published is seen as “special”.
What I call a “special issue fraud operation” seems to have been a massive success for MDPI, which can be clearly seen in Figure 1. More than 70 percent of their profit is based on their number of special issues. Virtually all of MDPI’s remarkable growth in recent years can be correlated to merely special issues alone.

On the contrary, in professional journals, the number of special issues is few because these issues are supposed to be special. They are meant to cover a particular topic that deserves more attention in the scientific community due to its actuality and relevance. Usually, these issues are proposed by a group of well-achieved scholars and will eventually get accepted or rejected by the journal’s Editor-in-Chief (EiC).
However, in MDPI’s market strategy, the journal itself and its editorial staff send out a massive amount of invitations for their special issues. They know how to play into the researcher’s vanity and desire to embellish their CVs. There is officially an editorial board, but it is unclear how much involved they are in this process other than exploiting their names for advertising.
As seen in Figure 2, the biggest paradox is that MDPI Sustainability has been found to be the least sustainable journal. Over the whole year of 2021, it released a new unique issue every third hour. With more than 3000 special issues, this journal alone attracted more than 36 000 articles solely based on its aggressive advertisement campaign.

If you believe that these advancements in profit are something that advances science, you should think once more. The outcome is that each publication's actual value and impact are rapidly degrading, which is a massive disservice to science. In September 2021, the national publication committee of Norway decided to label Sustainability as a level “X” journal. As a result, it no longer receives any acknowledgment in terms of publication points in Norway.
MDPI promise that they are, on average, rejecting 60 percent of the articles that get submitted. As a result, they want to give the impression that low-quality research will not get through their peer review system. However, these claims haven’t been peer-reviewed, as they cannot be backed up with quantifiable evidence.
I have been a regular reviewer for MDPI journals in the recent past. Several times I have experienced evaluating very poor research that has still been published in MDPI journals on short notice without taking my criticisms into account. Moreover, the turnaround times are extremely fast, which ensures that they receive quick revenue from article processing fees (APCs).
For the research that is not immediately accepted, the MDPI editorial-administrative staff usually recommends resubmission of the same article to ensure that the rejection does not result in reduced revenue for MDPI.
Within short notice, the rejected article is normally resubmitted by the same authors and with a brand new manuscript number. In this way, MDPI can have a moderate rejection rate while virtually all submitted articles will easily get through the system in the end. In reality, the actual rejection rate is much closer to zero than the claimed 60 percent.
MDPI is still a recognized publisher of open science, increasing its reputation by receiving research submitted by good scholars as well. As a result, it becomes a borderline publisher that superficially meets the criteria to ensure not being categorized as a predatory publisher while, in reality, being much closer to predatory practices. I believe that these corrupt practices need to stop as we see other publishers are tempted to start adopting these controversial strategies.