Why study demography?
● Demography is the study of human population
● It encompasses the study of the size, structure
and distribution of populations, and how
populations change over time due to births,
deaths, migration, and aging.
● Demographic analysis can relate to whole
societies or to smaller groups defined by criteria
such as education, religion, or ethnicity.
Data and Methods
● Demography relies on large data sets that are
primarily derived from censuses and
registration statistics (i.e., birth, death, marriage
● Large data sets over long periods of time (e.g.,
the U.S. census is conducted every 10 years)
are required to develop trends in demographic
indicators, like birth and death rates.
● demographers focus on specific indicators of
● Two of the most important indicators are:
– birth rates or fertility/fecundity
– death rates or mortality
● Also look at migration
Fertility and Fecundity
Fertility, in demography, refers to the ability of females to produce healthy
offspring in abundance.
● Fecundity is the potential reproductive capacity of a female.
● Some of the more common demographic measures used in relation to
fertility and/or fecundity include:
– crude birth rate: the annual number of live births per thousand people
– general fertility rate: the annual number of live births per 1000 women of childbearing
age (often taken to be from 15 to 49 years old, but sometimes from 15 to 44).
– age-specific fertility rate: the annual number of live births per 1000 women in
particular age groups (usually age 15-19, 20-24 etc.)
– total fertility rate: the number of live births per woman completing her reproductive
life if her childbearing at each age reflected current age-specific fertility rates
Mortality refers to the finite nature of humanity: people die.
Mortality in demography is interested in the number of deaths in a given
time or place or the proportion of deaths in relation to a population.
● Some of the more common demographic measures of mortality include:
– crude death rate: the annual number of deaths per 1000 people
– infant mortality rate: the annual number of deaths of children less than 1 year old per
thousand live births
– life expectancy: the number of years which an individual at a given age can expect to
live at present mortality rates
The Demographic Transition
● The demographic transition is a model and
theory describing the transition from high birth
rates and death rates to low birth and death
rates that occurs as part of the economic
development of a country.
● In most post-industrial societies, birth and death
rates are both low. The transition from high
rates to low rates is referred to as the
Population Growth and
● Overpopulation indicates a scenario in which
the population of a living species exceeds the
carrying capacity of its ecological niche.
● Overpopulation is not a function of the number
or density of the individuals, but rather the
number of individuals compared to the
resources they need to survive. In other words,
it is a ratio: population over resources.
Effects of overpopulation
High birth rates
Lower life expectancies
Lower levels of literacy
Higher rates of unemployment, especially in urban
Insufficient arable land
Little surplus food
Poor diet with ill health and diet-deficiency diseases (e.g. rickets)
Low per capita GDP
Increasingly unhygienic conditions
Government is stretched economically
Increased crime rates resulting from people stealing resources to survive
Mass extinctions of plants and animals as habitat is used for farming and human settlements
● Migration refers to population transfers or
people moving, typically from one country to
another, but also within countries.
● Urbanization is the physical growth of urban
areas as a result of global change.
● The United Nations projected that half of the
world's population would live in urban areas at
the end of 2008.
Effects of Urbanization
● Urbanization can increase costs for homes
● Urbanization can lead to changes in the
environment, creating effects like the urban
● Urbanization can change how people feel about