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Demographics

Demographics is the scientific study of populations, with emphasis on size, structure, and distribution, and how these attributes change over time due to fertility, mortality, and migration.

Key measures include population size, age structure, sex distribution, fertility rates, mortality rates, life expectancy, birth

Data are drawn from censuses, vital statistics, surveys, and administrative records. Demographers use methods such as

Trends include demographic transition from high to low fertility and mortality, aging populations in many regions,

Applications include planning for infrastructure, health, education, and social security; market research and political representation; and

and
death
rates,
and
migration
flows,
as
well
as
indicators
of
urbanization
and
population
density.
cohort-component
projections
and
life-table
analyses,
along
with
population
pyramids
to
illustrate
age
and
sex
structure.
rising
life
expectancy,
and
increased
global
mobility.
Dependency
ratios
capture
the
burden
of
dependents
on
the
working-age
population.
monitoring
of
inequality
and
development.
Limitations
include
data
quality,
undercounting,
definitional
differences,
privacy
concerns,
and
potential
biases
in
surveys.