Postdoctoral mobility and returnees' careers in Italian academia

This paper investigates the relationship between international postdoctoral stays and academic career advancement among researchers returning to the Italian university system. Using a unique dataset of Italian PhD holders observed over a 30-year period, we analyze how international postdoctoral stays are associated with two key career outcomes: (i) the time between PhD completion and first appointment as Assistant Professor (time-to-entry), and (ii) the time between Assistant Professor appointment and promotion to Associate Professor (time-to-promotion). We identify international postdoctoral stays by tracing foreign affiliations in researchers' publication records and examine how their association with career progression is moderated by institutional inbreeding, home-country linkages, and the persistence of international research networks. To explore these relationships, we apply a Cox proportional hazards model combined with entropy balancing. Our findings were validated by using curriculum vitae information for a subsample of researchers. We found that international postdoctoral stays are associated with slower entry into the academic system but are positively related to shorter time-to-promotion. Notably, this association is strongest for researchers promoted at universities other than their alma mater. We also observe that maintaining a strong home-country publishing network is associated with quicker entry as Assistant Professor, while sustained collaboration in postdoc-period co-author networks is linked to faster promotion to Associate Professor.