Research

This study analyzes 1709 Japanese municipalities (2012–2022), most of which experienced population decline, to examine whether urban components like public facilities, road networks, and urban areas shrink correspondingly. Using correlation, regression, and cross-tabulation methods, the study finds that while these components expanded during population growth, they largely failed to downsize during decline, with many municipalities showing continued expansion despite shrinking populations. This mismatch raises concerns about inefficiency in urban services and increased fiscal burdens due to excess infrastructure relative to declining population.

This research note examines how infertility concerns and medically assisted reproduction (MAR) affect Japanese women's ability to reach their ideal family size, finding that over a third of married women report infertility concerns, which are increasingly cited as a barrier to achieving fertility ideals across all educational groups. The study shows that births from MAR treatments have narrowed the gap between ideal and actual fertility by about one third, though highly educated women are more likely to seek and receive such treatment than others.

This research note exploits Japan's 1966 "Firehorse" zodiac superstition, combined with mismatches between school and calendar years, as a quasi-experimental instrument to estimate the causal effect of education on marriage and fertility among roughly 1.8 million Japanese women. Using a difference-in-differences approach, the study finds that increased education modestly delays marriage and childbearing—smaller effects than prior research suggested—without raising permanent singlehood, while more educated women show higher labor force participation at marriage and marry slightly younger spouses. The authors conclude that education's direct impact on family formation is moderate, suggesting institutional factors beyond education are important for understanding declining marriage and fertility trends in East Asia and for designing family policy.

This study proposes a framework linking fertility desires to marriage timing to explain "lowest-low" fertility in East Asia, using Japan as a case study where parenthood is normatively tied to marriage. Using discrete-time hazard models on longitudinal data, the authors find that both women and men without a desire for children marry later than those who desire children, and that uncertain attitudes toward parenthood delay marriage for men (partly due to reduced partner-seeking effort) but not for women. The findings suggest that pro-natalist policies focused solely on married couples may be mistargeted, given the strong connection between fertility intentions and marriage decisions.