[7] Between 2016 and 2020, the number of peer-reviewed papers published by MDPI grew significantly, with year-over-year growth of over 50% in 2017, 2018 and 2019,[6] attracting attention to their very fast article processing times.
[28] Some journals published by MDPI have also been noted by the Chinese Academy of Sciences and Norwegian Scientific Index for lack of rigor and possible predatory practices.
[7][35] The journal Molecules was established in 1996 in collaboration with Springer-Verlag (now Springer Science+Business Media) in order to document the chemical samples of the MDPI collection.
[citation needed] MDPI Verein co-organized several academic conferences, including the International Symposium on Frontiers in Molecular Science.
In 2014, various virtual conferences were hosted in the areas of synthetic organic chemistry, material sciences, sensors, and sustainability.
In 2015, MDPI co-organized two physical conferences with and at the University of Basel, the 4th Internationational Symposium on Sensor Science and the 5th World Sustainability Forum.
[citation needed] MDPI as a publisher of open-access scientific journals was spun off from the Molecular Diversity Preservation International organization.
The special issues are collections of papers on a specific topic, handled by guest editors (as opposed to members of the journal's editorial board).
[39] MDPI was included on Jeffrey Beall's list of predatory open access publishing companies in February 2014.
[27] Beall's concern was that "MDPI's warehouse journals contain hundreds of lightly-reviewed articles that are mainly written and published for promotion and tenure purposes rather than to communicate science.
"[28] Following Beall's criticism of MDPI, the Open Access Scholarly Publishers Association (OASPA) conducted an investigation in April 2014.
This investigation was based on the controversy surrounding two papers, one in Life,[48] the other in Nutrients;[49] the listing of Nobel Prize winners on the website; the roles of editorial board members and of Shu-Ki Lin within the company; and the functions of the different office locations.
[57] In January 2023, Zhejiang Gongshang University (浙江工商大学) in Hangzhou, China, announced it would no longer include articles published in Hindawi, MDPI, and Frontiers journals when evaluating researcher performance.
[58][59] In December 2020, the Chinese Academy of Sciences published a list of journals that may suffer from issues of scientific quality and other risk characteristics.
However, most researchers felt the primary driving force to publish with MDPI journals was their fast article turnaround time.
[4] MDPI has been criticized by scientific bodies in Norway, Finland, and Denmark that rank academic journals for their quality and relevance.
[68][69][70] Among their descriptions, they call MDPI a Chinese organization with a "small artificial office in Switzerland",[2] and "a money-making machine" that plays on the desire of academics to embellish their CV[69][70] (see publish-or-perish).
Changes made to the article added caveats and toned down inflammatory language, however the core conclusions remained the same.
These are outside the organization's 3 level scale and receive the same points in funding applications as popular articles or publications without peer-review.
[91][92] In 2013, another MDPI journal, Entropy, published a review paper claiming glyphosate may be the most important factor in the development of obesity, depression, attention deficit hyperactivity disorder, autism, Alzheimer's disease, Parkinson's disease, multiple sclerosis, cancer, and infertility.
[96] The article claimed that obesity rates in Australia increased in the same timeframe that sugary soft drink consumption declined by 10%.
[97] In 2016, MDPI journal Behavioral Sciences published a review paper that claimed that watching pornography is a cause of erectile dysfunction.
[98] After critics raised concerns, an independent review by the Committee on Publication Ethics (COPE) recommended that the article be retracted, based on issues including an unusual editorial process in which the listed journal editor declared that he "was not involved in the final decision regarding correction/retraction/authorship," an inaccurate and incomplete conflict of interest declaration that failed to disclose author connections with anti-pornography activist groups, failure to obtain informed consent from the study subjects, and failure to protect the identities of those subjects.
[100] In 2019, MDPI journal Psych published an editorial on race and intelligence by Richard Lynn,[101] who had previously had his emeritus status revoked due to his promotion of discredited sexist and racist views, such as scientific racism.
[102][103] MDPI later issued an expression of concern and changed the status of the article from editorial to opinion, three months after publication.
[104] According to science journalist Angela Saini, Psych had also published other similar work defending scientific racism.
Shortly afterwards, the journal published an "expression of concern" regarding the article and opened an investigation into the review process.
[71] In 2020, the numbers were even higher, reaching "as surprisingly high as 788 special issues in Sustainability, 830 in Applied Sciences, and 846 in Materials.
[112] This number of special issues leads to "concerns about how peer review can be conducted effectively at this scale" as well as questions about the thematic relevance to the journal.