Economics · Lesson 12

Population: theories, structure & the labour force

JAMBWAECNECO

What the syllabus asks

JAMB: Population: theories (Malthusian, demographic transition); census (importance and limitations); size, growth, structure and distribution; optimum population; labour force, efficiency and mobility of labour

WAEC: Population: meaning, size and growth; census (uses and problems); theories of population (Malthusian theory, demographic transition); optimum, over- and under-population; population structure (age, sex, occupational and geographical distribution); dependency ratio; rural–urban migration; labour force and working population; population policy

NECO: Population: meaning, size and growth; census (uses and problems); theories of population (Malthusian theory, demographic transition); optimum, over- and under-population; population structure (age, sex, occupational and geographical distribution); dependency ratio; rural–urban migration; labour force and working population; population policy

What you will learn

Define population and explain how births, deaths and migration change its size.
Explain the meaning, uses and problems of a census, with reference to Nigeria’s census history.
Calculate birth, death, natural-increase, growth and dependency rates.
State and evaluate the Malthusian theory and the demographic transition theory.
Distinguish optimum, over- and under-population.
Describe the age, sex, occupational and geographical distribution of population.
Explain the labour force and the effects of population growth on economic development.

Key points

Population = number of people in a defined area at a given time; data from census, vital registration and surveys.
Census uses: planning, revenue allocation, representation, business, income per head.
Nigerian censuses: 1952/53, 1962 (cancelled), 1963, 1973 (cancelled), 1991 (≈88.99m), 2006 (140,431,790).
CBR, CDR per 1,000; natural increase = CBR − CDR; growth includes net migration.
Malthus (1798): population GP, food AP; positive and preventive checks; weakened by technology and falling birth rates.
Demographic transition: death rate falls first, then birth rate; stage 2 = population explosion.
Optimum population gives maximum output per head and moves with technology.
Dependency ratio = (0–14 + 65+) ÷ (15–64) × 100; Nigeria has a youthful, broad-based pyramid.
Labour force = employed + unemployed seeking work; unemployment rate = unemployed ÷ labour force.
Rapid growth helps only if output and jobs grow faster than population.

Start here: Meaning of population and sources of data

When the Local Government in Kano plans how many primary schools to build, or when a bank in Onitsha decides where to open a new branch, both need to know how many people live in an area, how old they are and what they do. This is the study of population.

Population is the total number of people living in a defined area (a town, state or country) at a particular time.

Why economists study population

People are both producers (they supply labour, one of the factors of production) and consumers (they create demand for goods and services).
Governments need population data to plan schools, hospitals, roads, housing and water supply.
Firms use it to estimate the size of markets.
Population figures are used to share revenue and political representation between states and local governments.

Sources of population data

Census: a complete count at one time (see 12.2).
Vital registration: continuous recording of births, deaths and marriages. In Nigeria the National Population Commission is responsible for registering births and deaths.
Sample surveys: questioning a sample of households, such as demographic and health surveys, to estimate birth rates, health and so on.
Migration records: immigration and passport records of people entering and leaving the country.

Worked example 12.1

State which source of data each person would use: (a) a planner who needs the total number of people in every LGA; (b) a health officer who wants to know how many babies were born last month in a district; (c) a researcher who wants to estimate family size from 5,000 households.

(a) A census: only a full count gives every LGA total.
(b) Vital registration: births are recorded continuously.
(c) A sample survey.

Census; vital registration; sample survey

⚠️ Common mistake: defining population as "the people of a country". You must include a defined area and a particular time; population keeps changing.

Try it yourself. Give one reason why people are both producers and consumers.

Show solution

They supply labour to produce goods and services, and they demand goods and services to satisfy their wants.

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Practice questions

1. The number of people living in an area at a given time is its

population
labour force
density
census

Show answer

A: population
Population is counted by a census.

2. Nigeria's 2006 census figure was about

88 million
200 million
56 million
140 million

Show answer

D: 140 million
140,431,790 people.

3. Crude birth rate is measured per

10,000 people
1,000,000 people
1,000 people
100 people

Show answer

C: 1,000 people
Births per 1,000 of the population in a year.

4. CBR = 40 per 1,000 and CDR = 15 per 1,000. The natural increase rate is

0.25%
2.5%
5.5%
25%

Show answer

B: 2.5%
(40 − 15) ÷ 1,000 = 25 per 1,000 = 2.5%.

5. According to Malthus, population grows in

geometric progression while food grows in arithmetic progression
arithmetic progression while food grows geometrically
the same progression as food
a constant amount

Show answer

A: geometric progression while food grows in arithmetic progression
Thomas Malthus, 1798.

Key words

Population: The total number of people living in a defined area at a particular time.
Census: An official count of the whole population of a country at a given time, with details such as age, sex and occupation.
Vital registration: Continuous official recording of births, deaths and marriages.
Crude birth rate: Number of live births per 1,000 people in a year.
Crude death rate: Number of deaths per 1,000 people in a year.
Infant mortality rate: Deaths of babies under one year per 1,000 live births in a year.
Natural increase: Birth rate minus death rate.
Net migration: Immigrants minus emigrants.
Optimum population: The population size that, with given resources and technology, gives the maximum output per head.
Over-population: Population larger than the optimum, so output per head is lower than it could be.
Under-population: Population smaller than the optimum, so resources cannot be fully exploited.
Dependency ratio: Ratio of dependants (under 15 and 65+) to the working-age population, usually × 100.

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