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Lam, David, and Leticia Marteleto. 2008. "Stages of the Demographic Transition from a Child's Perspective: Family Size, Cohort Size, and Children's Resources." Population and Development Review, 34(2): 225-252.
While the basic empirical regularities of falling mortality, falling fertility, and resulting patterns in population growth rates are well known, little attention has been paid to the implications of these changes for the dynamics of family size and cohort size. These dynamics have a number of intriguing features, the most important of which is the tendency for family size and cohort size to move in opposite directions during a significant part of the demographic transition.
We have proposed a characterization of the demographic transition from a child’s perspective that has three stages. Children born in Stage 1 face increases in both family size and cohort size, the result of increased child survival. Children born in Stage 2 experience declining family size, as falling fertility overtakes falling mortality, but face continued increases in cohort size as the result of population momentum. Children born in Stage 3 experience declines in both cohort size and family size and face less competition for resources at both the population and family levels. Using a simple model of the demographic transition, we demonstrate the key components of these stages: a race between falling fertility and falling mortality in Stage 1, a race between falling fertility and population momentum in Stage 2, and concurrent declines in cohort size and family size in Stage 3. This model suggests that Stage 2 will be a typical feature of the demographic transition, usually lasting two or three decades. For this research, we analyze changes in fertility, mortality, surviving family size, and cohort size for eight countries with good census microdata: Brazil, Costa Rica, Ecuador, Kenya, Mexico, South Africa, Uganda, and Vietnam.
PMCID: PMC2546613. (Pub Med Central)
Countries of focus: Brazil, Costa Rica, Ecuador, Kenya, Mexico, South Africa, Uganda, Vietnam.