The first question has been answered by a literature study conducted by the TIB Leibniz Information Centre for Technology and Natural Sciences on empirical papers 2010-2021. The following fields of impact were examined:
Attention in science, quality of scientific publications, knowledge transfer, productivity, use of publications, diversity and economic effects.
The results confirm the known advantages of OA in six areas of impact. Only the often-mentioned citation advantage of OA could not be clearly confirmed empirically – but neither could it be refuted.
At the same time, it was recognised that there is a need for further research, e.g. on the influence of OA on the career opportunities of researchers.