The word demography is a combination of two Greek words “demos” and “graphos” meaning “human beings” and “writing/measurement” respectively. A Belgian Statistician “ACHILLE GUILLARD” was the first man to pronounce and designate the term “Demography” in the article “éléments de statistique humaine ou demographique comparee” (elements of human statistics or comparative demography).
Definition: Duncan and Hauser write
“Demography is the study of the size, territorial distribution, and composition of population, changes therein, and the components of such changes, which may be identified as natality, mortality, territorial movement(migration) and social mobility(change of status).”Duncan and Hauser(1972,p.2)
Sources of Demographic Data
Previously, the empirical documents for demographic studies were censuses and vital registration only. However, after the World War II, sample surveys have started increasing the substantial progress of providing the data for demographic studies and researches and it has possibly been able to provide demographic data with useful information.
Demography as a subject
Demography, as a subject agrees, in principle, that it has two definitions: such as, a narrow definition and a broader definition like all other definition. In narrow terms “demography” is defined as the scientific study of human populations, primarily with respect to their size, their structure and their development (Van de Walle,1982). Thus, it as scientific study of human populations in their aggregate with regard to their size, composition or structure, spatial distributions and developments or changes in these over time.
In it’s broader definition, it is also called “POPULATION STUDIES”, it does not only deal with the levels and changes in the size, composition and distribution of the population but also does deal with the causes and consequences of the levels and changes. In it’s broader view, demography overlaps with a number of other disciplines such as Economics, Sociology, Social Psychology, Statistics, Mathematics, Geography, Medicine, Political Science, Law, Anthropology, and Reproductive Physiology (Bogue, 1969; UN 1958) etc. Thus, demography, in its broader definition, known as “Population Studies”, is multidisciplinary in nature, and of late, as well as, from the recent past; it has attracted researchers from different disciplines such as Economics and Sociology who have made valuable contributions to its development.