Influences of return migration on international collaborative research networks: cases of Japanese scientists returning from the US

The emigration of scientists facilitates the formation of international networks. However, are ties in such networks maintained after the scientists return to their respective home countries? Using data from the Web of Science, this paper analyzes whether Japanese migrant scientists returning from the US maintain the collaborative research network ties that they formed during their stay in the US and, if so, what features of these ties contribute to maintaining these relationships. The geographical distance between the US and Japan can impede the transfer of knowledge that is transmitted most effectively through face-to-face interactions. However, social proximity may compensate for geographical distance. Accordingly, the ties that Japanese scientists have formed with other Japanese scientists living in the US are more likely to be maintained than the ties that they have formed with scientists of different ethnicities. Social proximity was also measured by past experiences in collaborative research. The ties to scientists with whom Japanese scientists collaborated more frequently or co-produced papers with higher citation counts are more likely to be maintained after the scientists return to Japan. When collaborative research of American and Japanese scientists is worthwhile, they obtain mutual benefits through a ‘give and take’ in which they compensate for one partner’s lack of knowledge by the other partner’s knowledge. In a research field with which the developmental gap between the US and Japan is great, ties are less likely to be maintained.