The distribution of reproduction during a fertility transition: declining spread of parenthood in Brazil

Demographers have a rich understanding of the fertility transitions that have been observed in many contexts. Yet, we lack evidence to explain whether long-run declines in fertility levels are accompanied by simultaneous changes in reproductive variability. This is important because reproductive variability—the concentration and dispersion of childbearing—may help to better explain fertility trends and predict population change. We address this gap with a case study of Brazil, which is a well-known example of fertility transition, using microdata on fertility by education for cohorts born 1910–1970. We contribute by using multiple measures of variability in completed fertility, studying how these measures change during an entire transition, how they relate to cohort fertility rates, and how this evidence varies by education. Reproductive variability declines across the Brazilian fertility transition—for measures of concentration and dispersion—although this is less evident for dispersion measures that adjust for levels of children ever born. We also find considerable differences by education and evidence that several measures of variability are predictive of fertility decline, highlighting a promising avenue for future research. Moreover, our findings suggest that conclusions based on one measure of variability may only provide a partial understanding of population dynamics.