Populations can change through three processes: fertility, mortality, and migration.…

Populations can change through three processes: fertility, mortality, and migration. Fertility 1 the number of children that women have and is to be contrasted with fecundity (a woman's childbearing potential). Mortality is the study of the causes, consequences, and measurement of processes affecting death to members of the population. Demographers most commonly study mortality using the Life Table, a statistical 2 that provides information about the mortality conditions (most notably the life expectancy) in the population. Migration refers to the movement of persons from a locality of origin to a destination place across some predefined, political boundary. Migration researchers do not designate movements 'migrations' 3 they are somewhat permanent. Thus demographers do not consider tourists and travellers to be migrating. While demographers who study migration typically do so through census data on place of 4 , indirect sources of data including tax forms, and labour force surveys are also important. Demography is today widely taught in many universities across the world, 5 students with initial training in social sciences, statistics or health studies.