Demographic Transition Theory

The stage model

Warren Thompson (1929) classified countries into three groups by their birth and death rates, and Frank Notestein (1945) and Kingsley Davis (1945) systematized the idea as the theory of demographic transition. The classic model has four stages. Stage one is preindustrial society, where high birth and death rates keep population nearly stable. In stage two, better food supply, sanitation and medicine cut mortality sharply while fertility stays high, so population explodes. In stage three, urbanization, expanding education, women's rising status and contraception lower fertility and population growth slows. In stage four both rates are low and population stabilizes. Many now add a fifth stage in which births fall below deaths and population declines. Omran's (1971) epidemiologic transition, a shift in causes of death from infectious to chronic degenerative disease, complements stage two.

Causes and evidence

Notestein located the cause of fertility decline in modernization: industrialization and urbanization turned children from sources of labor and old-age security into costly dependents needing education, and falling infant mortality reduced the need for many births. John Caldwell (1976) argued that fertility falls when intergenerational wealth flows reverse, from children-to-parents to parents-to-children. The Princeton European Fertility Project (Coale and Watkins, 1986), however, found that late nineteenth-century European fertility decline spread along linguistic and cultural lines more than levels of economic development, suggesting that the diffusion of ideas and norms mattered. Ronald Lee (2003) judged that the transition fundamentally reshaped human longevity, families and economies over three centuries. When fertility falls after mortality, the working-age share of the population rises; Bloom et al. (2003) called this the demographic dividend and counted it among the sources of East Asia's rapid growth, including South Korea's.

Critiques and the second transition

Critics call the theory a descriptive generalization of Western experience. The timing and pace of the stages vary widely, and some regions, such as sub-Saharan Africa, have seen fertility declines stall. Kirk (1996) judged that the theory has weak predictive power yet remains demography's central framework. Contrary to the prediction of stability after stage four, fertility in many developed countries kept falling below replacement (about 2.1 children). Lesthaeghe and van de Kaa (1986) proposed the second demographic transition, explaining this by value change toward individualism and self-realization along with more cohabitation and later marriage (Lesthaeghe, 2014). Myrskylä et al. (2009) reported that fertility may rise again at very high levels of human development. The United Nations (2024) projects world population to peak at about 10.3 billion in the mid-2080s. South Korea, with a 2023 total fertility rate of 0.72, the world's lowest, is a leading example of post-transition ultra-low fertility.

FAQ

What is demographic transition theory in simple terms?

As societies develop, death rates fall first and population surges, then birth rates fall too, until both births and deaths are low.

What is the second demographic transition?

It explains why, even after population stabilizes, value changes such as individualism and self-realization reduce marriage and childbearing, pushing fertility persistently below replacement.

Sources reviewed: 2026-10-26

References

1. Thompson, W. S. (1929). Population. American Journal of Sociology, 34(6), 959–975.
2. Notestein, F. W. (1945). Population: The long view. In T. W. Schultz (Ed.), Food for the World (pp. 36–57). Chicago: University of Chicago Press.
3. Davis, K. (1945). The world demographic transition. Annals of the American Academy of Political and Social Science, 237(1), 1–11.
4. Coale, A. J., & Watkins, S. C. (Eds.). (1986). The Decline of Fertility in Europe. Princeton: Princeton University Press.
5. Caldwell, J. C. (1976). Toward a restatement of demographic transition theory. Population and Development Review, 2(3/4), 321–366.
6. Lesthaeghe, R., & van de Kaa, D. J. (1986). Twee demografische transities? In D. J. van de Kaa & R. Lesthaeghe (Eds.), Bevolking: Groei en Krimp (pp. 9–24). Deventer: Van Loghum Slaterus.
7. Lesthaeghe, R. (2014). The second demographic transition: A concise overview of its development. PNAS, 111(51), 18112–18115.
8. Omran, A. R. (1971). The epidemiologic transition. Milbank Memorial Fund Quarterly, 49(4), 509–538.
9. Lee, R. (2003). The demographic transition: Three centuries of fundamental change. Journal of Economic Perspectives, 17(4), 167–190.
10. Bloom, D. E., Canning, D., & Sevilla, J. (2003). The Demographic Dividend. Santa Monica: RAND.
11. Kirk, D. (1996). Demographic transition theory. Population Studies, 50(3), 361–387.
12. Myrskylä, M., Kohler, H.-P., & Billari, F. C. (2009). Advances in development reverse fertility declines. Nature, 460(7256), 741–743.
13. United Nations, Department of Economic and Social Affairs, Population Division (2024). World Population Prospects 2024. New York: United Nations.