Gender inequality in academic promotion 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 74,344 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 timeline 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 timeline are more significant in early-career transitions than in later transitions, although gaps have narrowed in more recent cohorts. Survival-based robustness checks that account for right-censoring confirm that Stage 1 remains the primary locus of gender inequality, but also indicate that completed-transition comparisons can overstate female advantage in promotion timeline in recent cohorts, especially in STEM. By foregrounding promotion timeline as a core dimension of career stratification, this study discusses how institutional structures and environments differentially shape academic career advancement by gender, providing evidence relevant to Japan and comparable academic systems.