Thomas Klebel and Tony Ross-Hellauer, reporting in Quantitative Science Studies on their analysis of 1.5 million articles in the DOAJ:
The observed forces clearly perpetuate the system of cumulative advantage inherent to academia, as well-funded research groups are better able to secure OA publications in prestigious journals with high APCs, leading to citation advantages and further funding down the line. We believe that this demonstrates the impact of APC pricing on the scholarly landscape and that these charges may have a chilling effect on opportunity and equality for researchers from less prestigious or less wealthy institutions. Such stratifications in publishing, favouring traditionally-advantaged actors, will only exacerbate historical inequalities…
It’s getting harder and harder, with every study, to ignore that APCs are excluding authors in patterned, North-South ways.