A New Perspective on Replacement Fertility

The connections between mortality and fertility have far-reaching implications – for broad subjects like population growth, family building and increasingly, the study of natural disaster. Scholars have long posited familial mechanisms that raise fertility in response to mortality increase, including the “replacement” effect, in which parents increase fertility following a child’s death to achieve a desired family size. Despite having a strong theoretical foundation, the volitional replacement effect has slim empirical support. The gap in evidence is often attributed to the methodological challenge of identifying a causal, behavioral fertility response to shifts in mortality. We revisit the replacement question in the context of an unexpected environmental mortality shock: the 2004 Indian Ocean tsunami. We analyze detailed longitudinal, population-representative data collected before and after the tsunami in Indonesia. Using satellite measures of environmental destruction, we demonstrate a substantial and sustained fertility increase attributable to the tsunami. With data on fertility intentions, family mortality, and women’s completed fertility by 2009, we find robust evidence of a volitional replacement effect. We conclude with a discussion of the implications for disaster-afflicted populations.