Abstract: This article1 describes the possibilities to analyze open access (OA) publishing in the Netherlands in an international comparative way. OA publishing is now actively stimulated by Dutch science policy, similar to the United Kingdom. We conducted a bibliometric baseline measurement to assess the current situation, to be able to measure developments over time. We collected data from various sources, and for three different smaller European countries (the Netherlands, Denmark, and Switzerland). Not all of the analyses for this baseline measurement are included here. The analysis presented in this article focuses on the various ways OA can be defined using the Web of Science, limiting the analysis mainly to Gold OA. From the data we collected we can conclude that the way OA is currently registered in various electronic bibliographic databases is quite unclear, and various methods applied deliver results that are different, although the impact scores derived from the data point in the same direction.