Explain population growth and its economic effects
Use birth, death and migration rates to analyse changes in population size and structure.
Cambridge IGCSE Economics 0455 / IGCSE (9–1) Economics 0987, 2027–2029 Version 1. Apply each model to the stated evidence and qualify conclusions where effects depend on context. Practice is original and self-checked; it is not a Cambridge paper, mark scheme or official grade.
Before you begin
- No prior economics study is assumed. Read the scenario for the decision-maker, the market or economy involved, the time period and the evidence supplied.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What can a youthful age structure increase?
What you will learn
- Define population-rate terms
- Explain cross-country differences
- Assess effects of population size and structure
Population changes through natural change and migration
Birth and death rates are typically measured as births or deaths per 1,000 people per year; check the dataset definition and period. Net migration is immigration minus emigration. Immigration is movement into a country and emigration is movement out.
Rates vary with income, healthcare, education, employment, age structure, policy, conflict and environment. Explain relevant factors rather than assuming one cause applies everywhere.
Size and structure affect demand and supply
A larger population can expand labour supply and the market for goods and services, but also raises demand for housing, infrastructure and public services. An ageing or youthful structure changes the balance of workers and dependants.
An optimum population is the size at which output per head is highest in the model. It is a theoretical comparison, not a simple real-world target; effects depend on resources, technology and public services.
Pause and explain
Why might an ageing population create pressure on public finances?
Worked example
A country has a high birth rate and net emigration. Explain why total population change cannot be inferred from birth rate alone.
Show the worked solution
- Births add to population; deaths reduce it.
- Net emigration reduces population when more people leave than enter.
- The total change depends on all three components.
Answer Population change depends on births minus deaths plus net migration. A high birth rate alone is insufficient to determine whether population rises.
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Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A country records 18 births per 1000 people, 10 deaths per 1000 and net emigration of 3 per 1000. Find the approximate population change per 1000 before other adjustments.
Give me a hint
Natural change is births minus deaths; then add net migration.
Compare my reasoning
- Births minus deaths = 18 − 10 = 8.
- Net emigration subtracts 3.
- Approximate net change = 5 per 1000.
Population rises by approximately 5 per 1000 from these components, before any measurement issues.
Look for these in your work
- Natural change correct
- Migration sign correct
- Net result stated
A fast-growing city has more workers and more demand for transport and housing. Explain both potential benefits and pressures.
Give me a hint
Consider production capacity and service demand.
Compare my reasoning
- More workers may increase labour supply.
- A larger market can attract firms.
- Infrastructure and housing need to expand to avoid congestion and shortages.
The city may gain workers and a larger market, supporting production and business opportunities. It also needs housing, transport and services; without capacity, congestion and living costs may rise.
Look for these in your work
- Labour benefit stated
- Market benefit stated
- Capacity pressure stated
Two countries have the same population growth rate but different age and gender structures. Explain why their labour supply and service needs can differ.
Give me a hint
A growth rate does not reveal who is in the population.
Compare my reasoning
- Age structure affects the share of working-age people.
- Gender structure and participation can affect labour supply.
- Different age groups create different education, health and care needs.
The same growth rate can conceal different working-age shares and participation patterns. The countries may therefore have different labour supplies and demand for schools, healthcare or care services.
Look for these in your work
- Age structure linked
- Participation considered
- Service needs contrasted
Common mistakes
- Confusing immigration with emigration
- Assuming a larger population always raises output per head
- Treating an optimum population as a fixed universal number
What can you explain now?
What is net migration?
Compare with the explanation
Immigration less emigration
It measures net movement across a country's borders.
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What is net migration?
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