How birth rates, death rates and net migration can vary between countries

Economic Development – Population (IGCSE Economics 5.3)

Learning objective

Explain why birth rates, death rates and net migration differ between countries and assess the impact of these differences on economic development.

Key definitions (per 1,000 population per year)

• Birth rate: number of live births.
• Death rate: number of deaths.
• Net migration: immigrants – emigrants.
• Population growth rate (exam‑style approximation):
  Growth % ≈ [(Birth – Death + Net Migration) ÷ 10]
• Age‑structure: proportion of the population that is
  • Youth (0‑14 years)
  • Working‑age (15‑64 years)
  • Elderly (65+ years)
• Dependency ratio:
  Dependency ratio = [(Youth + Elderly) ÷ Working‑age] × 100 (expressed as a percentage). Separate ratios can be shown for youth‑ and elderly‑dependency.
• Gender balance: male‑to‑female ratio (often expressed as the number of males per 100 females). Influences labour‑force composition and can be altered by cultural practices or migration patterns.
• Optimum population: the size at which a country can maximise economic welfare – enough labour to produce goods and services, but not so large that resources become overstretched. It is judged by comparing the availability of natural resources, infrastructure, capital and the skill level of the workforce with the size of the population.

Factors that cause variation

1. Birth‑rate influences

• Level of economic development – higher incomes usually lower fertility.
• Education, especially for women – more schooling → later marriage & fewer children.
• Access to contraception and family‑planning services.
• Cultural and religious norms (e.g., preference for large families).
• Urbanisation – city life often reduces desired family size.
• Government policies: family‑planning programmes, tax incentives or penalties for having children.
• Gender balance: societies with a strong male bias (e.g., son‑preference) may experience higher birth rates as families try for a male child.
• Environmental sustainability: concern over resource scarcity can lead governments to promote smaller families.

2. Death‑rate influences

• Quality and accessibility of healthcare (maternal care, immunisation, emergency services).
• Nutrition and food security.
• Living standards, housing, sanitation and clean water.
• Prevalence of disease and effectiveness of public‑health measures.
• Environmental conditions (pollution, climate‑related hazards).
• Government health policies (vaccination campaigns, disease‑control programmes).

3. Net‑migration influences

• Economic opportunities – jobs, wages, career prospects.
• Political stability, safety and respect for human rights.
• Education and skill‑acquisition prospects (students, skilled workers).
• Family reunification and immigration policies.
• Environmental factors – climate change, natural disasters, sea‑level rise.
• Gender balance: migration often favours one gender (e.g., male labour migrants), which can skew the sex ratio in both sending and receiving countries.

Typical patterns in different country groups

Population structure and related concepts

• Age‑structure: the three‑group breakdown (youth, working‑age, elderly) is the basis for calculating dependency ratios.
• Dependency ratios:
  • Youth‑dependency ratio = (Youth ÷ Working‑age) × 100
  • Elderly‑dependency ratio = (Elderly ÷ Working‑age) × 100
  • Total dependency ratio = (Youth + Elderly ÷ Working‑age) × 100
• Gender balance: a skewed sex ratio can affect marriage markets, labour‑force participation and long‑term fertility trends.
• Optimum population: judged by:
  • Availability of natural resources (land, water, energy)
  • Capacity of infrastructure (housing, transport, health, education)
  • Quantity and quality of capital and technology
  • Skill level of the labour force
  When the population exceeds the point at which these factors can be sustained, economic welfare falls; when it is below, there is under‑utilisation of potential output.
• Environmental sustainability: high population pressure can increase pollution, over‑use of water and land, and raise the risk of resource‑related conflicts. Sustainable development policies aim to balance population size with environmental carrying capacity.

Implications for economic development – link to macro‑economic aims

• Labour force and growth:
  • Rapid natural increase (high birth – death gap) expands the labour supply, potentially raising economic growth if jobs are created.
  • If job creation lags, the result is higher unemployment and pressure on public services.
• Dependency ratios and fiscal policy:
  • High youth‑dependency → greater spending on education and health, lower short‑term savings, possible pressure on price stability if demand outstrips supply.
  • High elderly‑dependency → higher pension and health‑care costs, larger fiscal deficits, and potential upward pressure on interest rates.
• Net migration:
  • Positive net migration can offset a shrinking labour force, bring new skills, and boost aggregate demand – supporting full employment and growth.
  • Negative net migration (brain‑drain) reduces the skill base, can lower productivity and weaken the balance of payments by reducing export capacity.
• Gender balance:
  • Skewed sex ratios may limit labour‑force participation of the under‑represented gender, affecting potential output and long‑run growth.
• Environmental sustainability:
  • Fast population growth can increase demand for energy and raw materials, raising import bills and potentially threatening the balance‑of‑payments equilibrium.
  • Policies that promote smaller families can help keep resource use within sustainable limits.

Worked example – calculating population growth rate

Using the exam‑style formula for Japan (birth = 7, death = 10, net migration = 2):

Growth % ≈ [(7 – 10 + 2) ÷ 10] = [-1 ÷ 10] = ‑0.1 %

Interpretation: Japan’s population is falling by about 0.1 % per year.

Suggested visual aid (exam‑friendly)

Bar chart comparing the three rates (birth, death, net migration) for two contrasting countries – e.g., Niger (high birth, low migration) and Japan (low birth, positive migration). This replaces the population‑pyramid, which is no longer examined.

Exam practice questions

1. Define birth rate, death rate, net migration and dependency ratio and explain how each is measured.
2. Using the data in the table, calculate the approximate annual population growth rate for Japan.
   Answer: (7 – 10 + 2) ÷ 10 = ‑0.1 % → population decline.
3. Discuss two reasons why a country’s birth rate tends to fall as it develops.
4. Explain how a high level of positive net migration can affect the dependency ratio in the receiving country.
5. Evaluate the long‑term economic consequences for a country with a rapidly ageing population.

Key summary points

• All three demographic rates are expressed per 1,000 population per year.
• Developed countries usually have low birth and death rates; developing countries often have high birth rates and higher death rates.
• Net migration can either reinforce or offset natural population change.
• Age‑structure determines youth‑, elderly‑ and total dependency ratios, which influence government spending, tax revenue and savings.
• Gender balance and environmental sustainability are now explicit factors in the syllabus.
• Understanding variations in size, structure and migration helps predict labour‑market trends, dependency ratios and the likely impact on the four macro‑economic aims: growth, full employment, price stability and balance of payments.