The growing importance of the globalisation of R&D activities is evident from a large number of case studies, statistics, and analyses, both at the national and corporate level.2 Yet, it is still difficult to describe the phenomenon statistically, because systematic data which map the internationalization of R&D are still rare. Some progress has been made in using patterns of patent filings and inventor collaboration as evidence of R&D globalization, but a systematic picture of the R&D inputs used by firms has not materialized yet. Firm-level data capture R&D investments irrespective of location. The usually employed data sources such as Compustat or others do not contain any information on the geographic distribution of a firm’s R&D activities. Conversely, most of the national R&D statistics (which are then summarized by the OECD and published via, inter alia, stats.oecd.org) capture all R&D activities within national territorial boundaries, but not the R&D performed abroad by firms headquartered in the respective national territory. In some cases the agencies collecting these data have extended their questionnaires to develop a notion of the extent of international R&D activities, but there has not been any systematic measurement over time.3