AccScience Publishing / IJPS / Volume 7 / Issue 2 / DOI: 10.36922/ijps.v7i2.354
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On the empirical study of fertility transition: A case for application of age-adjusted measures in multivariable analysis

Pedzisai Ndagurwa1* Clifford Odimegwu2
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1 Gauteng City-Region Observatory, University of the Witwatersrand, Johannesburg, South Africa
2 Demography and Population Studies, University of the Witwatersrand, Johannesburg, South Africa
IJPS 2021, 7(2), 60–70;
Submitted: 17 September 2022 | Accepted: 8 November 2022 | Published: 25 November 2022
© 2022 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution -Noncommercial 4.0 International License (CC-by the license) ( )

Among studies of factors driving fertility transitions, the cumulative children ever born (CEB) has been treated as the dependent variable in multivariable models. Some of these studies have cited total fertility rates (TFRs) in their rationales for investigating the determinants of fertility transition. However, CEB and TFR (which are computed from age-specific fertility rates) are notably disparate measures of fertility. The aim of this study was to argue that where TFRs are cited as a basis for an investigation of driving factors of fertility transitions, the dependent variable in the multivariable modeling ought to be an adjusted measure of fertility. The study applied trend analysis to examine the extent to which CEB and age-specific marital fertility rates (ASMFR) reflected trajectories of the trends of total marital fertility rates (TMFRs) in Ghana, Kenya, Rwanda, and Zimbabwe. Multivariable analysis based on the two-fold Oaxaca-Blinder decomposition technique was applied to examine how using ASMFR compared to CEB impacts the understanding of factors of fertility change, using the case of Zimbabwe. Trend analysis showed that ASMFR was more effective in reflecting fertility trends and measuring the role of associated factors. The results from multivariable analyses show that a case can be made for the use of adjusted measures in the understanding of factors of fertility transition.

Marital fertility
Children ever born
Age-specific marital fertility rate
Total marital fertility rate
Decomposition analysis
University of the Witwatersrand’s Faculty of Humanities
National Institute for Humanities and Social Sciences (NIHSS)- Council for the Development of Social Science Research in Africa (CODESRIA) doctoral fellowship

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Conflict of interest
The authors certify that they have no conflicts of interest to declare.
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International Journal of Population Studies, Electronic ISSN: 2424-8606 Print ISSN: 2424-8150, Published by AccScience Publishing