I was recently asked to review for an MDPI open access journal. Is this a reputable publishing company? Their website suggests that they are 15 years old, and only do open-access publishing. The journal has a 3-year impact factor of around 2, which is not unreasonable for my field.
The peer review process generally differs between predatory and non predatory journals.
- Given that they have solicited a review from you is a positive sign.
- If you don't know the authors and the work before hand, then that is another positive sign.
- If the article you are reviewing is good, then that would be a third positive sign.
- Finally, if you make comments in your review and the authors address them in the published version, that would be a final positive sign.
If on the other hand you know the authors and work, it is crappy, and the comments are ignored, that would be a bad sign.
Based on the amount of spam that I receive from them (mostly calls for papers in special issues), the fact that their automated emails do not feature a “unsubscribe me” link, and the fact that I did not manage to be removed from their lists after several complaints, I would say that they are not a respectable publisher.
I don't know how long they have been around, but most of their journals in my field (chemistry) were very recently created: see there for a full list, which you can sort by journal creation date. Their older journal, Molecules, has a less-than-stellar impact factor of 2.4. Its editorial board, apart from the occasional celebrity or two, is unremarkable.
As a conclusion: I think they surf on the popularity of open access journals, but I don't consider them serious players.
In my very personal opinion MDPI is an reputable publisher, but their journals are not first-class. I did a review for them once, and the peer review process was smooth. Also, I knew the field of the reviewed paper very well, so I guess they selected me as a reviewer carefully. But I really can speak only for one of their journals.
On the other hand, I won't publish in their journals since they charge quite a bit for the open access, and there are other options in my field which are free for authors and subscribers. Also I don't like to be spammed with their "newsletters".
Added: I have recently seen this post reporting a problematic peer-review case with an MDPI journal. This lets me doubt, if my initial judgement was right. I suspect, it might depend on the journal.
About a year ago, I was asked to become editor-in-chief for one of their journals. I asked myself the same question. After doing some background research, I came to the conclusion that MDPI was, albeit rather "young", a reputable publisher.
I have worked with them for a little while now and have just started as editor-in-chief on another journal under MDPI with a specific focus on my area of research. My interaction with the editorial manager is very efficient. Surely, we will not compete with Nature and Science for high profile manuscripts, but I am absolutely convinced that both journals will do well with high quality papers and manuscripts.
I recently reviewed a review article about a specific disease for an MDPI journal. I did not know the authors, who were from an institution in China. I was absolutely an appropriate reviewer, as most of my publications in the last 8 years or so are on the same disease.
I won't say that the article was great, but it did carefully cover the topics well and pulled in some of the current challenges. The journal and authors were certainly responsive to review comments and efficient in processing them.
In summary, everything about the process indicated that MDPI is acting like a reputable journal--making a real effort to do good work and provide a venue. What I hope new journals can do is build a good set of publications and solid review process that is perhaps less subject to some of the biases in big-name established journals. Bias, for example that lets a big name in the field get by with an easy review, but is unreasonable or simply rejects new players in a field.
tl; dr: probably reputable, but they are controversial, and a significant number of academics don't like MDPI.
I used to work in publishing so this answer cuts much closer to the publisher's world than the academic one. It's also going to be very long, so I'm splitting it into sections.
Size: MDPI has grown very large. It's approximately the fifth largest publisher in the world by paper volume, publishing >100k papers a year. It's still growing very quickly and might have overtaken Taylor & Francis at this point. This number is large enough that it's improbable they are all bad papers based only on number. E.g. for comparison OMICS, which is much more commonly regarded as disreputable, is not nearly the size of MDPI. How did MDPI grow so fast? The main reason appears to be ...
Review time: MDPI claims a median time from submission to publication of only 39 days. From the perspective of other publishers this time is absurdly fast, in fact many publishers won't even calculate this number because the time taken for peer review is not something that's under their control. MDPI got this fast by accelerating their production time to nearly zero (more on this later), and by attempting to control the time taken for peer review anyway. From my conversations with an MDPI employee & by looking at the blogosphere of academics, they appear to do this by:
- Requesting reviews very quickly. When reviewing for MDPI you could be asked for a review in 7(!) days. This doesn't mean they are compromising on review quality however: after all, most students will always submit their assignments just before the deadline, and most reviewers will do the same with their reviews. In other words, the request effectively says "are you free to give a quick review? If not, we'll ask someone else." MDPI are able to ask this question because their reviewers are invited by the editorial staff, not editorial board members. Full-time editorial staff can do things like react instantly when a review is submitted, or invite new reviewers the moment one declines. MDPI also have a staggering number of editorial staff per journal - I'm told in the vicinity of ~30 for a journal that publishes ~3000 articles per year - to provide 24-hour coverage. Adding fuel to the fire is that the editorial staff will usually hold advanced degrees in the field of the journal. See also the review process bullet point below.
- Authors are also requested to revise their articles quickly. Their editorial staff tailors the amount of revision time to the difficulty of revisions requested. They can do this because they usually hold advanced degrees in the field of the journal. The time given to revise can be as short as 2 (!) days, although it can also be significantly longer if new experiments are requested.
- Finally, they accelerated their production time to nearly zero - taking only a few days from acceptance to uploading XML files online. This timetable is crazy; for comparison at other publishers I worked at, the target is 25 working days. The only way to get it to go faster is by having more manpower, which MDPI appears to have done - each journal also has hundreds of production staff that literally start working on the paper the instant it arrives on their desk. The MDPI employee who told me the above claimed MDPI has >10,000 employees. This doesn't match their history page, implying that most of these >10,000 employees are freelance and/or part-time, which makes sense given that the workload in journal publishing ebbs and flows.
Their astonishing speed does mean they can claim a legitimate competitive advantage over other publishers. It also means that if you submit/review/edit for MDPI, you can expect very fast response times. It's fairly common on Academia.SE to get questions about how long peer review seem to take at some journals (example). The way MDPI is set up means this will never happen to them.
Summary of this section: I don't see any evidence to think MDPI compromised their peer review process to achieve this speed. They're trying to work around the process in ways that defy industrial standards, but can conceivably work.
Review process: The MDPI employee I talked to said the typical review process goes like this:
- Paper is submitted.
- Paper is shown to an editorial board member specializing in the field of the paper (remember the journal staff have advanced degrees), who makes the decision whether to send it for peer review. If the decision is no, desk reject.
- The journal staff invites reviewers (remember the journal staff have advanced degrees).
- Editorial board member makes the decision based on reviews received.
The argument for doing it this way is that MDPI wants to reduce the workload of their editorial board members as much as possible. To do #2 and #3, they hire at advanced level. Other publishers I worked at tended to leave #2 to the editor-in-chief and #3 to the editorial board member assigned to the paper.
This kind of arrangement definitely cuts the time taken for peer review, but the impact on review quality is hard to quantify. I want to think it isn't worse (because I've done it before and the reviews received didn't seem worse), but some academics will be critical.
This also explains why MDPI's editorial boards often have hundreds of people without an editor-in-chief, and can also explain why people seem to have divergent experiences with MDPI's peer review process (because if my experiences elsewhere are anything to go by, journal staff are more variable than editorial board members).
Summary of this section: I don't see anything organically wrong with how MDPI do their peer review. At least, their intentions are benign. However, some people will object to the editorial board not handling everything (example).
Production process: Same as standard, except they engage advanced degree holders in the relevant field to do copyediting. This is expensive, but doable; many professional copyediting companies offer this. From my conversation with the MDPI employee, I know they are outsourcing their copyediting a lot (apparently there was even one editorial board member who wanted to be involved with copyediting). I don't know if they are engaging these copyediting companies, however.
Article processing charges: MDPI charges about 1000-2000 Swiss Francs per article. Relatively speaking this is somewhat lower than average among big publishers.
They are rather open about how they spend the APC. Based on my knowledge of publication fees, their numbers are believable: there are fixed costs that cannot change, but journals that charge less also get less of a marketing budget, and they also have less leeway to provide discounts/waivers. The numbers indicate that the less expensive journals are making a net loss per paper, and the more expensive journals are subsidizing the less expensive ones - which is also my experience. Production costs are a bit higher than they have to be, but given that they're hiring an army of advanced degree holders, it's not surprising.
For the people who associate "predatory/disreputable" with "high profit margin", the numbers indicate their profit margin is 1-6% per article, which is definitely on the low side.
Special issues: the MDPI employee I talked to appeared to have a different conception of "special issue" than the common one, which is an extra "special issue" of a subscription-based journal with a set number of issues per year. MDPI's special issues simply appear to be collections of papers on that topic with an invited guest editor. The special issues are often very generic (e.g. this special issue with theme "Focus on Dark Matter" could very well be its own journal, and indeed is).
From my perspective the special issues are simply a way to get more academics to collaborate with MDPI.
Publishing metrics: MDPI does well on many of the standard metrics publishers look at. All numbers in this section are from this source.
- Overall rejection rate of 60%, which is not high but also not low.
- Their citability is improving. "In 2016, only 27 of its 169 titles were indexed on SCIE (Science Citation Index of Web of Science) and were on track to get an Impact Factor. By 2019, its leading journals were generally as citable as the average articles in the fields where they compete (more on that below). In summer 2020, 71 of MDPI’s 250 titles had an Impact Factor." (For those unfamiliar with this, to get an impact factor the journal needs to be indexed by the Science Citation Index, which is very hard; clearing this hurdle puts any new journal on very solid footing to be self-sustaining.)
- "All ten titles improved their citability for content published in the same year (Immediacy Index) from 2015-19, and eight of them improved their citability from 2018 to 2019. Six of the titles had a better Immediacy Index in 2019 in their leading research category than articles of other journals, and two of them had a better Immediacy Index than articles of the selective ERA 2018 journals (25,017 journals in the Excellence in Research for Australia 2018 journal list)." (Immediacy Index here is how often the articles in the journal are cited in the same year they are published)
- They don't have a higher retraction rate than the rest of the industry. "[MDPI] reported 19 retractions in 2019, equivalent to 0.5 retractions per 1,000 papers (assuming that retractions refer to year t-2). As a point of contrast, I could locate 352 papers on Elsevier's ScienceDirect that included the phrase 'this article has been retracted' in 2019, implying 0.5 retractions per 1,000 papers (again, assuming that retractions refer to year t-2)."
- They are not reliant on either a single country or a single subject area (see Fig. 6 & 7 of source).
Summary: from other publishers' point of view, as long as one neglects the name, MDPI is a healthy publisher, maybe even one to be envied.
Controversies: MDPI is controversial primarily because Jeffrey Beall blacklisted them back in 2013. Although they were removed in 2015 after appeal, Beall still called them a "borderline case". I wrote more about Beall's list in this answer; the brief summary is that it's not a given that any unbiased observer will agree with Beall's assessment.
One can still look at the controversies themselves on MDPI's Wikipedia page. In general it seems like MDPI have increased their publication standards and have gotten less controversial since 2013. Post 2015, the only really controversial incident one could associate with predatory publishing is the 2018 resignation of several editorial board members. Examining this in more detail the board members argue they were being pressured to accept mediocre papers. However, from the article it's clear that the argument is a well-known one in publishing, and has to do with whether one should demand novelty in articles. I wrote as much in the answer above:
Many OA journals do indeed review lightly. For example I once attended a talk by a Springer spokesperson who talked about a journal which reviews for correctness, not novelty (can't find the journal now, but PLOS ONE has the same policy). Viewed one way this is laudatory - it makes peer review less random by eliminating one completely subjective facet! Viewed another way, this is terrible - it makes it seem as though the journal will publish old results known for hundreds of years as long as the author is willing to pay. Which is closer to the truth? You'll have to come to your own conclusions.
If you believe that this style of reviewing is terrible, as the Nutrients editors apparently did, then you'll conclude MDPI is predatory. If you take the other view that this style of reviewing is laudatory, you'd ignore the entire incident as much ado over nothing. It's not clear-cut; some academics have even published an article defending another journal that outright didn't conduct peer review.
Aside from the above there is also this:
Simen Andreas Ådnøy Ellingsen questioned the quality of MDPI's peer review based on his experiences as a reviewer for the publisher; he wrote that he was only given one week to review a paper, that he recommended rejection, that the paper was then simply published without further comment, and that he never was in contact with any editor.
But this also doesn't look like very problematic, because editors can choose to accept a paper that reviewers recommend reject, the one week review time is part of MDPI's standard operating procedure, and given that the journal staff are inviting peer reviewers, it's not surprising that Simen Andreas Ådnøy Ellingsen was never in contact with a member of the editorial board.
There doesn't seem like much else in the controversies section post-2015, so I conclude by argumentum ex silencio that there is no smoking gun that they're disreputable. At least, they've raised their standards since Beall blacklisted them in 2013.
Email spam: This is perhaps the most annoying thing about MDPI. Submit or review a paper and they send you all sorts of emails about X or Y, some of which there is no realistic chance you'll be interested. Odds are this contributed to MDPI's growth actually, simply because it's how spam works.
It is possible receiving these spam emails on topics way out of one's expertise is due to a failure by the journal staff (i.e., they are lazy/incompetent). If so, I would be pretty disappointed because they are supposed to have advanced degrees. Still, I also have to admit that there are good and bad employees everywhere, and there are certainly others who received relevant emails.
If you believe that only disreputable publishers spam, then MDPI are clearly disreputable. On the other hand if you believe that "disreputable" = "bad peer review", then their spamming doesn't seem related. At least they seem to respect requests to unsub.
Finally: Many people approve of MDPI - their sheer size is an indication. They have hundreds of thousands of authors, and tens of thousands of editors. Equally, many people disapprove. I have no numbers for this, but here are some examples. Therefore however one looks at it, MDPI is controversial. You might want to make up your own mind on them.
MDPI is an academic publisher with a relatively unique model (among major publishers) that fits a specific need in the marketplace. (Full disclosure - I have mid-authored several papers that ended up in MDPI journals, although I won't submit there)
That need is volume. There are several countries which disproportionately weight volume of publications for promotion and funding. The large majority of MDPI papers are published from these countries. MDPI publishes quickly, with a very small minimum publishable unit, and reasonable apcs.
As you can imagine, the quality is overall poor. However, they do peer review, and at least attempt to avoid publishing complete garbage (there are highly reputable journals which aren't any better at keeping out utter nonsense PNAS I see you over there). The editorial staff isn't strong scientifically but do a good job of moving manuscripts through (they are very author friendly). Many of the journals are indexed, but I don't think I've ever cited anything from a MDPI journal - not because I won't or can't, just because there's nothing worth citing in my field.
Should you publish there? Well, if you're looking for funding from the NIH your biosketch is limited to a handful of papers, which means publishing a bunch of MDPI papers is pretty useless for you. If you included an MDPI paper in your biosketch it probably would hurt your investigator score. Mostly I see people dump dead projects into MDPI journals so students can get some publication. If you're in one of the funding systems where a large volume of papers is good for your career, go nuts. If you have actually good science you think other people will want to read, you can and should send it to better journals where it will be better peer reviewed.
Also the comments on the other answer about getting spammed with rfcs and review or editorial requests once you're in their system is spot on. I ended up just making it a spam filter problem cause I kept getting added to journals (most of which I could contribute nothing to because they're like oil exploration or something that's entirely out of my field).
Having more than 10% of your journals in ISI is more than an achievement. Most open-access journals don't even care because it is impossible to them. I think it is wrong to take open-access as fake or low quality, traditional journals are also becoming open-access and there are very serious open-access journals like PLOS. MDPI journals fall short compared to PLOS but they are respectable and are building their reputation. Charges are proportional to the journal reputation and most times can be waived if the author makes its case of lack of funding and it is completely independent of the review process.
The recent overview of the impact factors for various journals in MDPI: impact factors , show that there is significant credible scientific scholarship being disseminated. (eg. 'Catalysts' 3.4, 'Energies' 2.6, 'Entropy' 2.3). As of 2017, 'IEEE Access' has an impact factor of 3.5, impact factor on front page and its reputation is accepted and acknowledged.
I think that there is no definitive answer to this question.
I have recently published in a MDPI Journal (Materials) and my personal experiences with the journal were okay: The review times were short and the reviewers' comments were in no case different from other journals I previously published in. Communication with the editorial office went smoothly and without further complications. The editors of the special issue I published in are were well known in my field and reputable.
Unfortunately, since my paper was published, I am bombarded with spam mails. I don't want to speculate if this has to do with MDPI or could be a general problem of open-access.
What I have heard from others and read on the internet, however, differs greatly from my personal experience. From all of this, I personally got the feeling, that it is more about the individual journals and less about MDPI itself.