"Transitioning from a Conventional to a’‘Mega’ Journal: A Bibliometric Case Study of the Journal Medicine"
Simon Wakeling et al. have published "Transitioning from a Conventional to a'‘Mega' Journal: A Bibliometric Case Study of the Journal Medicine" in Publications.
Here's an excerpt:
This study compares the bibliometric profile of the journal Medicine before and after its transition to the OAMJ model. Three standard modes of bibliometric analysis are employed, based on data from Web of Science: journal output volume, author characteristics, and citation analysis. The journal’s article output is seen to have grown hugely since its conversion to an OAMJ, a rise driven in large part by authors from China. Articles published since 2015 have fewer citations, and are cited by lower impact journals than articles published before the OAMJ transition.