The cost of open access: comparing public projects’ budgets and article processing charges expenditure

Open Access (OA) publication often entails payment of Article processing charges (APCs), particularly in the so-called Hybrid and Gold journals. The growth of Gold OA publications linked to the development of OA mandates has forced funders, research institutions, and researchers to develop strategies to pay APCs. Thus, this research tries to estimate the percentage of the budget of the projects funded by the Spanish State Plan for the Generation of Knowledge and Scientific and Technological Strengthening of the R&D&I, Spain's two main public project funding calls in Spain. The period studied is 2013–2019. Additionally, we study the relationships between publication intensity, funding attraction, and the availability of OA journals with APC expenditure at the area level. The results show that €45.87 million were spent on APCs, with most projects spending 3–8% of their budgets. However, numerous outliers with rates over 10% suggest further study on the role of APCs in the financial performance of the research activity. Estimations shown in the paper have to be taken cautiously as the APCs of the publications related to the projects studied in this analysis might not have been fully paid with the projects’ budget but using other funding strategies. Further research is needed to address the researchers’ decisions better when paying APCs. Finally, publication intensity, funding attraction, and the availability of OA journals are highly correlated with the investment in APCs in different fields. These results show that the current APC framework affects disciplines differently and raises questions about alternative publishing and funding models.