Page 66 - IJPS-7-2

International Journal of

Population Studies

RESEARCH ARTICLE
On the empirical study of fertility transition: A

case for application of age-adjusted measures in
multivariable analysis

Pedzisai Ndagurwa * and Clifford Odimegwu 2
1
1 Gauteng City-Region Observatory, University of the Witwatersrand, Johannesburg, South Africa
2 Demography and Population Studies, University of the Witwatersrand, Johannesburg, South Africa

Abstract

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
*Corresponding author:
Pedzisai Ndagurwa how using ASMFR compared to CEB impacts the understanding of factors of fertility
(pndagu@gmail.com) 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.
Citation: Ndagurwa, P. &
Odimegwu, C. (2021). On the The results from multivariable analyses show that a case can be made for the use of
empirical study of fertility transition: adjusted measures in the understanding of factors of fertility transition.
A case for application of age-
adjusted measures in multivariable
analysis. International Journal of Keywords: Marital fertility; Children ever born; Age-specific marital fertility rate; Total
Population Studies, 7(2):60-70.
https://doi.org/10.36922/ijps.v7i2.354 marital fertility rate; Decomposition analysis
Received: September 17, 2022
Accepted: November 8, 2022
Published Online: November 25, 2022 1. Introduction
Copyright: © 2022 Author(s). The interest in understanding fertility, the most studied of the demographic events,
This is an Open Access article carries various purposes which include to understand the factors driving trends in birth
distributed under the terms of the
Creative Commons Attribution rates, health implications of childbearing, and to predict future childbearing patterns
License, permitting distribution, based on prevailing fertility schedules (Ariho, et al., 2018; Ariho & Nzabona, 2019;
and reproduction in any medium, Colleran & Snopkowski, 2018; Liu & Raftery, 2020). In many cases, scholars have used
provided the original work is
properly cited. the total fertility rate (TFR) to highlight the need for the investigation of the determinants
Publisher’s Note: AccScience of fertility, and conducted multivariable analyses using the cumulative children ever
Publishing remains neutral with born (CEB) as the dependent variable (Adhikari, 2010; Al-Balushi, et al., 2020). While
regard to jurisdictional claims in
published maps and institutional many of these studies analyzed fertility at one point in time, those which compared two
affiliations. points in time with the aim of understanding drivers of fertility decline also relied on

Volume 7 Issue 2 (2021) 60 https://doi.org/10.36922/ijps.v7i2.354