The effect of data sources on the measurement of open access: A comparison of Dimensions and the Web of Science

Existing studies have provided estimates of the prevalence of OA publications ranging from 27.9% to 53.7%, depending on the data source and period of investigation. This paper aims at providing a comparison of the proportion of OA publishing as represented in two major bibliometric databases, Web of Science (WoS) and Dimensions, and assesses how the choice of database affects the measurement of OA across different countries. The paper concludes with a discussion of the cause and consequences of these differences, motivating the use of more inclusive databases when examining OA.