Week 3: Concepts of Demography

“description of the people.”

Demography Literally translated from the Greek,

Demography

The study of the size, territorial distribution, and composition of population and changes therein.

Population Size

The number of people in a given place at a given time.

Population Composition

The characteristics of a population according to age, sex, occupation, educational level, or other characteristics.

Population Distribution

The specific geographic location or spatial pattern of where people live.

Population

A collection of persons alive at a specified point in time who meet certain criteria. Example is the “population of Mindanao on April 2, 1999" and the "population of children in Iloilo on July 8, 2000.”

Population Projection

A demographic tool that provides a basis for statistical projections and helps governments in decision-making.

Birth, death, and migration.

Components of Population Growth

Age and Sex Composition

Factors that affect the social life of a population and reflect demographic changes.

Changes in Age Composition

Mainly result from changes in birthrates, which can increase the proportion of aged people and reduce the proportion of children.

Census

is usually conducted by a national government and attempts to enumerate every person in a country. In contrast to vital statistics data, which are typically collected continuously and summarized on an annual basis, censuses typically occur only every 10 years or so, and thus are not usually the best source of data on births and deaths.

A is the procedure of systematically acquiring and recording information about the members of a given population.

De Jure

Tallies people according to their regular or legal residence.

De Facto

Allocates people to the place where they are enumerated, normally where they spend the night of the day enumerated.

Sample Survey

Data gathered from a small number of people proportionate to the general population.

Registration System

A system that recordings of vital events.

Census, sample survey, and registration system.

Sources of Demographic Data

Natural Increase

The difference between the number of live births and deaths in a specified period.

Rate of Natural Increase (RNI)

The crude birth rate minus the crude death rate of a given region during a specified period. This rate gives the public health nurse an idea of how a certain country's population is growing.

Developing Countries and RNI

Developing countries typically have higher RNI values due to high fertility and health conditions that contribute to more deaths.

Absolute Increase per Year

The number of people added to the population per year.

Relative Increase

The actual difference between two census counts expressed as a percentage relative to the population size during the earlier census. Also known as the population growth rate, it measures the average yearly percentage change over the same time frame.

Sex Composition

The composition of a population according to sex; a basic demographic characteristic important for demographic analysis.

Sex Ratio

The ratio of males to females in a population.

Age Distribution

also called Age Composition, The proportionate numbers of persons in successive age categories in a given population.

High-Fertility Population

Usually has a large proportion of children and a small proportion of aged persons.

Median Age

The age that divides a population into two numerically equal groups: half are younger and half are older. It is a single index that summarizes the age distribution of a population.

Dependency Ratio

The age-population ratio of people typically not in the labor (0-14) force to those typically in the labor force (15-64) Measures the pressure placed on the productive population.

0-14 & 65+

Dependency ratio

People aged 15–64 years.

Productive Population

Age and Sex Composition

The universal characteristics of human populations are fundamental to understanding demographic processes of fertility, mortality and migration. Age composition may be summarized in terms of age groups (e.g., 0-15 years, 15-64 years and 65 or above). The age and sex composition is depicted at the same time using a population pyramid.

Population Pyramid: Horizontal Axis

The size of the population under investigation.

Population Pyramid: Vertical Axis

Age.

Population Distribution

The pattern of where people live. Denotes the spatial pattern resulting from dispersal of population, formation of agglomeration, and linear spread.

Urban-Rural Distribution

The proportion of people living in urban areas compared with those living in rural areas.

Crowding Index

An alternative measure of household crowding. It is defined as the number of usual residents in a dwelling divided by the number of rooms in the dwelling.

Population Density

The number of people per unit of land area. It is the people per sq. km of land area.