demography, science of human population. Demography represents a fundamental approach to the understanding of human society. Its primary tasks are to ascertain the number of people in a given area, to determine what change that number represents from a previous census, to explain the change, and to estimate the future trends of population changes. The demographer also traces the origins of population changes and studies their impact. Demographers compile and analyze data that are useful for understanding various social systems and for establishing public policy in such areas as housing, education, and unemployment.

Statistical study of human populations, especially with reference to size and density, distribution, and vital statistics. Contemporary demographic concerns include the global birth rates, the interplay between population and economic development, the effects of birth control, urban congestion, illegal immigration, and labour force statistics. The basis for most demographic research lies in population censuses and the registration of vital statistics.

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