Cohort Effects or Period Effects? Fertility Decline in South Korea in the Twentieth Century

PWP-CCPR-2011-001

Abstract

This study examines if the Korean fertility decline is driven by longterm cohort changes or by fluctuating period changes. By using a classic age–period–cohort model, a moment decomposition method, and a new summary fertility measure—‘cross-sectional average fertility’—I show that the Korean fertility decline is primarily driven by period changes and that delayed childbearing has important consequences for the onset of fertility decline. These findings are in line with the existing literature in fertility changes such as theories of fertility transitions and sociological accounts of fertility changes in Western countries in the twentieth century. The policy implications of these findings are also discussed.