Key Concepts in Demographics
Key Concepts in Demographics

Crude Birth Rate:  the total number of live births in a year for every 1000 people alive in the society

Crude Death Rate: the total number of deaths in a year for every 1000 people alive in the society

Demographic Transition Model: Explanation for the transformation of countries from having high birth rates and high death rates to low birth rates and low death rates

Dependency ratio:  proportion of the population that are dependents (under 15 or over 65).  It is calculated by  dividing the number of dependents by the total population (15-64).

Infant mortality rates: the number of deaths of children under the age of one per thousand live births.

Life Expectancy: The average number of years that an individual can be expected to live

Maternal mortality rates: is the death of a woman while pregnant or within 42 days of termination of pregnancy, irrespective of the duration and site of the pregnancy, from any cause related to or aggravated by the pregnancy or its management but not from accidental or incidental causes.

Population growth is the change in a population over time, and can be quantified as the change in the number of individuals of any species in a population using “per unit time” for measurement. Population growth is determined by four factors, births, deaths, immigrants, and emigrants.

Population Density: population divided by total land area.

Population pyramid:  Inverted bar graphs that show a wide population  base (younger population) with a narrow top (older population). Population pyramids show:  age distributions, dependency ratios of those under 15 and over 65, and sex ratios (males vs. females

Natural Increase Rate: The percentage of growth in a population. It is measured by subtracting the crude death rate from the crude birth rate. Usually developing countries have positive or high natural increase rate, while developed countries have a lower rate. Populations in developed countries may increase though due to migration.

Total Fertility Rates: the average number of children a woman will have in her childbearing years.