The fertility transition is one of the most profound changes to human living conditions, as the number of children per woman declined from five or more to around two or less. This decline occurred both in the western industrialised world and in many developing countries. One of the most debated issues concerns the evolution of the fertility differentials by socio-economic status (SES) before and after the fertility transition. Did the higher-SES families have more children than the low-SES groups before the fertility decline? How did these differentials evolve in various geographical settings during the transition?
According to some research on Western contexts, higher-SES groups had more children than low-SES groups before the transition, but were later the forerunners of the new reproductive behaviour when fertility started to decline. To better understand how the differences by SES developed during the transition, Martin Dribe (Lund University) and Francesco Scalone (University of Bologna) analysed large-scale micro-level population data from the IPUMS archive.
An analysis based on a global historical dataset
The authors used a very large dataset of 116 million married women in 91 countries from 1703 to 2018, taking into account 314 different census samples. The historical data for the 18th and 19th century referred to a group of North Atlantic countries. In contrast, the census samples after 1900 come from countries from all regions of the world. The dataset provides such a vast amount of information over time and space that it gives the analysis an unprecedented comparative perspective.
Dribe and Scalone calculated the average number of surviving children under the age of five and the number of children ever born per woman by SES (based on occupation of the father) for various transition phases. They identified the fertility regimes according to the national total fertility rates at each census.
In the pre-transitional regime, the highest-SES group had somewhat lower marital fertility than other groups in terms of children ever born and the number of surviving children. These relatively small initial SES differentials in marital fertility widened throughout the fertility transition, without converging to similar marital fertility levels later. In the post-transition period, the analysis confirms a similar negative relationship between SES and marital fertility.
A universal fertility pattern by socio-economic status?
These results questioned the universality of high marital fertility for high-SES groups before the transition. At the same time, the findings confirmed the high-SES groups as forerunners in the transition.
A universal negative SES gradient in marital fertility emerged under very different fertility regimes. The SES variations in fertility reflected fundamental differences in childbearing conditions, costs and benefits of children, and attitudes and knowledge surrounding deliberate fertility control within marriage.