Trajectory Divergence of Low Fertility and its Determinants: Evidence from International Comparison and China

Low fertility has spread from a small group of industrialised countries to most of the world, yet countries that fall below replacement level follow strikingly different paths thereafter. This thesis examines divergence within the low-fertility stage and its determinants, combining an international comparison with an analysis of China’s regional variation. Group-based trajectory modelling of total fertility rates for 218 countries and territories (2000–2023), multinomial and fixed-effects panel Logit models, spatial Durbin models for 319 Chinese prefectural cities, and long-difference regressions for 31 provinces trace fertility change from global pattern recognition to sub-national explanation. Three trajectories emerge: sustained low-level decline, moderate medium-level decline and slow high-level decline, differentiated by development, welfare, education and urbanisation. Among low-fertility countries, higher development raises the odds of stabilisation or rebound, while welfare acts mainly as a buffer. In China, fertility shows a stable west-high, east-low gradient reinforced by ethnic difference and spatial spillover. Coordinated packages of time, cash and service support relate more consistently to stabilisation than any single instrument.