Knowledge transfer (KT) from academia to industry is critical to support economic growth and to contribute to a local open innovation ecosystem. Research on university-industry knowledge transfer (UIKT) mainly focuses on codified knowledge. However, the vast majority of knowledge produced by academia is tacit and, in some cases, cannot be made explicit thus remaining embodied in individuals. Building on knowledge management theory and social network theory, this article proposes that socialization occurs in two forms, weak and strong socialization, and that strong socialization is needed for tacit UIKT. We propose that professional mobility of PhD graduates is an instrument to measure tacit UIKT. Through a database of the PhD graduates of a large pluridisciplinary European university, our results show that fields hardness and applicability have a positive effect on tacit UIKT and that alignment with national industrial specialization and free-movement policies influence tacit KT to the national industry. We contribute to knowledge management theory by exploring academic scientists’ mobility as a pipe of tacit UIKT as well as by extending the concept of socialization from intra-organizational to inter-organizational settings, by proposing the concepts of weak and strong socialization, and by showing how strong socialization and tacit UIKT depend on knowledge, industrial and political dimensions.
