Why Does Fertility Decline? Comparing Evolutionary Models of the Demographic Transition

Mary K. Shenk, University of Missouri at Columbia
Howard Kress, U.S. Centers for Disease Control and Prevention (CDC)
Mary Towner, Oklahoma State University

The literature on the demographic transition is crowded with competing theories, and scholars often call for more comprehensive, better-controlled studies that will help distinguish between different theoretical explanations. Yet comparative work has been uncommon and limited in scope. In this paper we work to address this problem by explicitly comparing several influential evolutionary models in order to determine which models or combinations thereof produce the most robust explanation for a rapid, recent demographic transition occurring in rural Bangladesh. To compare models rigorously, we use an evidence-based statistical approach employing model selection techniques derived from likelihood theory. This approach allows us to quantify the relative degree of support the data give to alternative models, even when they have overlapping predictions. Although model selection methods are ideal for comparative analysis, they are underused in demography. Data come from a new survey of 944 women from Matlab, Bangladesh designed specifically for comparative testing.