“We are sincerely grateful to scholars who give their time to peer-review articles submitted to MDPI journals. Rigorous peer-review is the corner-stone of high quality academic publishing.”

— The MDPI editorial team.

MDPI is a open access publishing power house with 390 published journals which get listed by Web of Science and Scopus. The company is officially based in Switzerland with offices in Serbia and China. It used to be listed as a predatory journal, but was removed in 2015 on appeal.
I personally had my doubt about this outfit and want to recall an experience that seemed to solidify my concerns.

In March of 2022 I received an invitation to review a paper on controlling a bipedal robot dynamically, submitted by 10(!) authors of an eastern European university. At this point I did not suspect anything and started to review. The opening paragraph started out quite weird and I very fast concluded that this paper has no merit and can’t be accepted. At this point the reviewer (me) has usually no idea about the reviewing history of the paper and how many other reviewers there are. My review at this point read:

The authors throw the reader off with their initial pragraph of the introduction. The statement “In general, a humanoid robot is statically stable if its stability is maintained at any point in time of its movement [1].”, is circular, lacks a proper definition of stability and references a paper which has nothing to do with humanoid robots or stability.
It is contradicted a couple of sentences later by “Humanoid robots are statically unstable, but they become dynamically stable at a moderate speed [2].”, again citing a completely irrelevant source. The sentences in between are fundamentally wrong” As long as construction of humanoid robot is less than three feet long, the support polygon degenerates to a line or point.”

The reviewer refuses at this point to continue the review.

and I alerted the editor as follows:

Reading the initial sentences of the introduction which is incoherent, contradictory, cites completely unrelated and irrelevant sources, and does not meet the minimum standard for proper English writing although it uses very simple sentences, I am under the impression that this paper has been auto-generated and refuse to review its content for the apparent lack of understanding of the topic at hand by the authors.

From my point of view that should have been sufficient evidence to flat-out reject the paper, but the story just got started. A couple of weeks later, a second invitation to review a revised version of this paper arrived and I, fairly confused at this point, started to take a closer look. I have indeed been the third reviewer, the first also advising to reject, though on a much more constructive note, which the paper from my point of view did not deserve. The second reviewer advised major revisions and an acceptence of the largely unaltered manuscript in the second round.

A bit of background on the paper and the special issue it was supposed to be published in. Among the authors there are, according to the university’s website:

  • 1 full professors (second author),
  • 3 associate professor (first and last author),
  • 2 assistant professors,
  • 3 lecturers holding a PhD degree,
  • 1 PhD student,

a rather unusual lineup and ordering. The editor of the special issue is coincidentally a professor from the same university (not an author, though) and decides to give this paper a second shot. It has been rejected for the special issue at last.

My complaint to the editorial board concerning the behaviour of the editor bordering on academic nepotism did go unanswered and the paper got published substantially unaltered in another MDPI publication.

As a result I am declining to review for MDPI (at this point I have accummulated 35 declined reviews) and am not considering this publisher for publishing my own review.

However, as this paper​1​ indicates, quality control is not only an issue for MDPI. But this seeming level of corruption compounds my pre-existing doubts about this publisher.

  1. 1.
    Meyyappan C, Ravichandran CS. Generation of Free Energy using a Compact Flywheel. 2022 International Conference on Electronics and Renewable Systems (ICEARS). Published online March 16, 2022. doi:10.1109/icears53579.2022.9751917