Cohort Process to the Lowest Fertility in Japan: Estimation and Projection of Lifetime Measures of First Marriage and Birth

Ryuichi Kaneko, National Institute of Population and Social Security Research, Japan

In this study, the cohort processes to the recent decline of the Japanese fertility rate to a historical low are analyzed in terms of lifetime measures of first marriage and birth by birth order. The measures include timing and prevalence indices of those life events estimated and projected with empirically adjusted Coale-McNeil model for the cohorts born in 1935-1970. The results indicate three distinct cohort phases to the lowest fertility in the society;(1) simple delay in marriages and birth due to compositional changes such as prevalence of high educational attainment in cohorts born in 1952 and after, (2) followed by the diffusion of never marrying caused by the further postponement among cohorts born in and after 1959, and (3) finally continuing diffusion of never-marrying at an accelerating pace caused by intentional retreat among cohorts born in and after 1965. These results suggest a general process to the lowest low fertility.