Demography, the interdisciplinary study of human populations. Demography deals with social characteristics of the population and their development through time. Demographic data may include (1) analysis of the population on the basis of age, parentage, physical condition, ethnicity, occupation, and civil position, giving the size and density of each composite division; (2) changes in the population as a result of birth, marriage, and death; (3) statistics on migrations, their effects, and their relation to economic conditions; (4) statistics of crime, illegitimacy, and suicide; (5) levels of education; and (6) economic and social statistics, especially those relating to insurance. See also Census; Ecology; Immigration; Migration; Population; Vital Statistics.