Developments in Demography

Abstract

A knowledge of the demographic structure of a society is of crucial importance for decision making. Demography is the social science that studies (1) the size, composition, and distribution of human populations; (2) the changes in population size and composition and distribution over time; (3) the components of these changes, i.e., fertility, mortality, and migration; (4) the factors that affect these components; and (5) the consequences of changes in population size, composition, and distribution, or in the components themselves. Demography is important because it makes many societal outcomes more likely than others. For example, the age structure of the U.S. population at the time of the introduction of Social Security made it more likely that this program was funded intergenerationally instead of building up individual annuities, because at that time, there were far fewer people in retirement ages than in working ages. The ultimate decision, however, was a political one.