“Publishing for free is great, but when journals start charging researchers fees, they don’t lose business. A new journal might introduce a fee after a free introductory period. For example, when eLife introduced a US$2,500 publication fee in 2017, it still published more articles in 2017 and 2018 than it had in 2016. Similarly, Royal Society Open Scienceintroduced a US$1,260 fee in 2018 and continued to grow….
I then looked at the four biggest commercial open-access publishers that relied on publication fees: BMC, Frontiers, MDPI and Hindawi. I tracked 319 of their journals, their listed prices and the number of research articles they published between 2012 and 2018. I fed this data into a statistical model and it showed academics preferred to publish in more expensive journals.
The two publishers who raised their prices the most, Frontiers and MDPI, also saw the most growth in the average number of articles in each journal….”