From drains to bridges: The role of internationally mobile PhD students in linking non-mobile with foreign scientists

Internationally mobile scientists, by engaging with foreign counterparts during their time abroad, often become conduits for knowledge and access to international networks. While the direct benefits of such mobility to the individuals are well-documented, this paper investigates how these benefits may extend to their non-mobile colleagues in the country of origin who collaborate with them. We investigate the internationalization of a scientific system by analyzing the role that Colombian scientists who pursue a PhD abroad play in connecting non-mobiles with foreign scientists. Combining data from CVs, scholarship programs, and OpenAlex publications, we reconstruct the mobility path of 19,158 Colombian scientists and their co-authorship networks from 1990 to 2021. We show that co-authoring with mobile scientists is a way for non-mobile scientists to establish co-authorship links with foreign scientists. While the diaspora has traditionally been viewed as a "brain drain", we find that not only returnees but also diaspora scientists connect local with foreign scientists. However, foreign collaborations appear largely dependent on the continued mediation of mobile scientists.