Developed by demographer Frank Notestein in 1945, this concept describes the typical pattern of falling death and birth rates in response to better living conditions associated with economic development. This idea is important, for it offers the hope that developing countries will follow the same pathway to population stability as have industrialized countries. In response to the Industrial Revolution, for example, Europe experienced a population explosion during the nineteenth century. Emigration helped alleviate overpopulation, but European couples clearly decided on their own to limit family size.

Notestein identified three phases of demographic transition: preindustrial, developing, and modern industrialized societies. Many authors add a fourth phase, postindustrial. In phase one, birth rates and death rates are both high with stable populations. As development provides a better food supply and sanitation, death rates begin to plummet, marking the onset of phase two. However, birth rates remain high, as families...