Cohort Fertility Measures Derived from WPP 2024: Global, Regional and Country Analysis

Giulia Gonnella, United Nations Population Division
Vladimira Kantorova, United Nations

Since the 2022 revision of the World Population Prospects (WPP), the global population dataset provides a complete set of fertility indicators for single age/single year from 1950 to 2100 for all countries and areas of the world. We use estimates and projections of single age-specific fertility rates from the 2024 revision of WPP (United Nations, 2024) to derive the fertility profiles and measures for the cohorts born between 1935 and 2055 offering a unique opportunity to understand what happened in those cohorts that have already aged out of the reproductive age and what will likely occur to cohorts who are still or will enter in the reproductive age span. While the cohort fertility measures and their comparison with the period measures have been extensively studied in some countries, especially those included in Human Fertility Database, we extend the analysis to all countries and areas of the world. The results presented in this paper confirm that fluctuations, drops or increases in the period fertility often had little (and never a sudden) impact on cohort-level fertility. Our contribution is to document these findings in the global context, without being restricted to a specific period, level of fertility or region.

Keywords: Fertility, Population projections, forecasts, and estimations, Quantum and tempo effects, Data and Methods

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