Gender inequality in academic promotion: Evidence from researchers’ career trajectories in Japan

Despite growing awareness of the lack of gender equity in academia, women's disadvantages in many aspects, including academic promotion, remain a persistent issue. Using career-trajectory data for 78,208 researchers from Japan’s researchmap platform, this study examines gender inequality in promotion trajectories across two key transitions: PhD to associate professor, and associate professor to full professor. Specifically, we examine how gender gaps in promotion time vary across cohorts, disciplines, and career stages, and further assess their associations with career-history and institutional factors. The results show pronounced heterogeneity over time and across fields. Gender disparities in promotion time are more significant in early-career transitions than in later transitions, although gaps have narrowed in more recent cohorts. However, substantial inequalities persist in both Humanities and STEM disciplines and are associated with the type of initial position, postdoctoral experience, inter-institutional mobility, disciplinary context, and university sector (public vs. private). By foregrounding promotion timeline as a core dimension of career stratification, this study dicusses how institutional structures and environments differentially shape academic career advancement by gender, providing evidence relevant to Japan and comparable academic systems.