MPIDR Working Paper

New cohort fertility forecasts for the developed world

Myrskylä, M., Goldstein, J. R., Cheng, Y. A.
MPIDR Working Paper WP-2012-014, 58 pages.
Rostock, Max Planck Institute for Demographic Research (February 2012)
Revised April 2013. This working paper has been published. See the link above for further information.
Open Access


The 1970s worries of the "population bomb" were replaced in the 1990s with concerns of population aging driven by falling birth rates. Across the developed world, the nearly universally-used fertility indicator, the period total fertility rate, fell well below two children per woman. However, declines in period fertility have largely been an artifact of later – but not necessarily less – childbearing. We produce new estimates of the actual number of children women have over their lifetimes – cohort fertility – for 37 developed countries. Our results suggest that family size has remained high in many "low fertility" countries. For example, cohort fertility averages 1.8 for the 1975 birth cohort in the 37 countries for which average period total fertility rate was only 1.5 in 2000. Moreover, we find that the long-term decline in cohort fertility has flattened or reversed in all world regions previously characterized by low fertility. These results are robust to statistical forecast uncertainty and the impact of the late 2000s recession. An application of the new forecasts analyzing the determinants of cohort fertility finds that the key dimensions of development that have been hypothesized to be important for fertility – general socioeconomic development, per capita income, and gender equality – are all positively correlated with fertility for the 1970s cohorts. Gender equality, however, emerges as the strongest determinant: where the gap in economic, political, and educational achievement between women and men is small, cohort fertility is high, whereas where the gap is large, fertility is low. Our new cohort fertility forecasts that document the flattening and even reversal of cohort fertility have large implications for the future of population aging and growth, particularly over the long term.
Keywords: World, cohort fertility, developed areas, forecasts
The Max Planck Institute for Demographic Research (MPIDR) in Rostock is one of the leading demographic research centers in the world. It's part of the Max Planck Society, the internationally renowned German research society.