5.3. Population
- Syllabus
- 0455–2027–2028
- Topic
- 5.3
- Level
- —
Learning objectives
5.3.1Factors that affect population growth• definitions of:• birth rate• death rate• net migration, immigration and emigration• how birth rates, death rates and net migration can vary between countries• reasons why birth rates, death rates and net migration rates can vary between countries5.3.2The effects of changes in the size and structure of populations• the concept of an optimum population• the effects of increases and decreases in population size and changes in the age and gender distribution of population
Explain why populations grow at different rates
Population changes through births, deaths and migration. The birth rate and death rate are the numbers of live births and deaths per thousand people per year. Immigration is movement into a country, emigration is movement out, and net migration is immigration minus emigration.
population change=natural increase+net migration=(births−deaths)+(immigration−emigration)
| Rate | Reasons it may differ between countries |
|---|---|
| birth rate | income, education, access to contraception, culture, child costs and infant survival |
| death rate | healthcare, nutrition, sanitation, age structure, conflict and disease |
| net migration | jobs, wages, safety, services, family links and migration rules |
Rates allow fair comparison between differently sized countries; raw numbers do not. A falling death rate can increase population growth even if the birth rate is unchanged.
Assess changes in population size and structure
A population's economic effect depends on its size and structure relative to available resources and jobs. The optimum population is the size that makes the best use of resources and gives the highest output or living standard per person under current conditions.
| Change | Possible benefits | Possible costs |
|---|---|---|
| larger population | bigger workforce and market, more specialisation | pressure on housing, services, jobs and resources |
| smaller population | less congestion and resource pressure | smaller workforce, tax base and market |
| ageing population | experience and demand for age-related services | higher dependency, pension and healthcare costs |
| more working-age people | larger labour supply and tax base | jobs and capital must expand to employ them productively |
| changed gender distribution | changes labour-force composition, household formation and demand; where it changes births, it also affects future age structure and workforce size | effects depend on participation, skills, norms and opportunities, not gender alone |
If population is below the optimum, an increase can raise output per person by using under-employed resources and enabling specialisation. Beyond the optimum, extra population may lower output per person when congestion and scarce resources dominate.
There is no fixed optimum forever: technology, resources, capital and institutions can shift it. Do not assume population growth or a gender imbalance has one automatic effect.