Demografija

Demografija, commonly translated as demography, is the scientific study of human populations. It examines the size, structure, and distribution of populations, as well as how and why they change over time. Changes are driven by three main processes: births, deaths, and international and internal migration. The field aims to describe current population characteristics and to forecast future trends to support policy, planning, and research.

Key indicators in demography include population size and growth, age and sex structure, life expectancy, fertility and mortality rates, and migration flows. Population pyramids illustrate age–sex composition; the total fertility rate and age-specific fertility rates measure fertility, while life expectancy and mortality rates summarize mortality. Migration influences urbanization, regional development, and labor markets, and many countries face aging populations and shifting dependency ratios as these dynamics unfold.

Data and methods: Demographers rely on censuses, vital statistics (births and deaths), and sample surveys, as well as population registers in some regions. Analytical methods include life-table analysis, cohort-component projection, and demographic transition modeling, complemented by statistical techniques to identify patterns, causes, and correlations. Projections support planning in health, education, housing, pensions, and infrastructure.

History and scope: The discipline has roots in early modern population statistics, with contributors such as John Graunt and later Thomas Malthus shaping its development. Modern demography integrates economics, sociology, epidemiology, and geography, and informs policy debates on population growth, aging, migration, and development.