Trends in Open Access Publishing With a Special Emphasis on MDPI (2018-2022)

In 2022, MDPI became the fourth largest publisher by their total number of indexed papers and the largest by their number of indexed open access papers per year. This analysis studies the distribution of MDPI papers in Web of Science and Scopus by country and by year. Scientists from Romania and Poland preferred to publish in MDPI journals to a higher degree than those from other countries. The contribution of publications in MDPI journals reported abnormally high numbers in other former Eastern Bloc countries, while the authors from the USA and England showed moderate interest in MDPI. The share of MDPI papers by year in all countries increased linearly over the recent few years, but the patterns in particular countries were very different. In Germany, France, and Japan, a “saturation” was observed; the number of MDPI papers in 2022 was only slightly higher than in 2021, whereas in South Korea, Spain, and Poland, the trend reversed in 2022, that is, there were fewer MDPI papers published in 2022 than in 2021.