Author : Mike Taylor
Differences between the impacts of Open Access (OA) and non-OA research have been observed over a range of citation and altmetric indicators, usually finding an Open Access Advantage (OAA). However, science-wide analyses covering multiple years, indicators and disciplines are lacking. Using citations and six altmetrics for 33.3M articles published 2011-21, we compare OA and non-OA papers.
The results show that there is no universal OAA across all disciplines or impact indicators: the OAA for citations tends to be lower for recent papers, whereas the OAAs for news, blogs and Twitter are consistent across years and unrelated to volume of OA publications. Wikipedia OAAs are consistently pronounced for all subjects except Humanities (HU) and Social Sciences. Patent OAAs for are strongest for Medical & Health Sciences (MHS) and Life Sciences (LS).
Uniquely, the OAAs for Policy citations is stronger for recently published research. These results support different hypotheses for different subjects and indicators. The evidence is consistent with OA accelerating research impact in MHS, LS and HU; increased visibility/discoverability being a factor in promoting the socio-economic impact; and that OA is a factor in growing online engagement with research. OAAs are therefore complex, dynamic, multi-factorial and require considerable analysis to understand.
