National ties of international scientific collaboration and researcher mobility found in Nature and Science

In recent decades, internationalization of research activities has increased, as demonstrated by the phenomena of international scientific collaboration and international mobility of researchers. This paper investigates whether the international scientific collaboration is explained by researchers’ motivation as well as their international migration. Using metadata from papers published in Nature and Science from 1989 to 2009, count data estimation was conducted. The results illustrate those researchers’ international migration and motivation, shown by both synergy and difference effects between countries, explain international collaboration. This implies that international co-authorship in recent decades has been based on researchers’ motivation as well as their networking. The positive result for synergy effects also means that pairs of countries with rich research environments tended to have more international collaboration, which may lead to the convergence of qualified research output in advanced scientific countries. Our findings also support the conclusion that researchers move to countries with better research environments, but networks created through international collaboration are not a factor in international migration. The relationship between international mobility and collaboration is confirmed as going in one direction, from mobility to collaboration.