Towards a global scientific brain: Indicators of researcher mobility using co-affiliation data

Motivation. Mobility of highly skilled workers has increased substantially since the 1990s. This increased mobility has a major impact on science and technology across the world (OECD, 2001; OECD, 2008) and is considered a central element in contemporary globalization (OECD, 2008; Docquier & Rapoport, 2012). The mobility of human capital is particularly important not only for the explicit sharing of resources, but also the exchange of tacit knowledge (Akerblom, 1996; OECD, 2008). Considerable attention, therefore, has been paid to the asymmetric flow of scholars between sending and receiving countries, with the latter tending to be economically wealthier (OECD, 2001; Docquier & Rapoport, 2012). The disparities caused by this asymmetry have been studied as brain drains and gains, in which receiving countries obtain a greater share of scientific capital to the detriment of the sending countries. Of particular concern has been the concentration of scholars in countries such as the United States. To account for these potential losses, many countries have created incentives for highly skilled scholars to stay in the country or to return after stays abroad (e.g., the Federation Fellowships in Australia) (Laudel, 2005). For example, in 2001, Science Foundation Ireland gave 10 scientific elite $67 million and planned another $530 million to try to retain Irish scholars and attract additional scientific talent (Pickrell, 2001).