Population & Population Change (Years 9–11) — Economics

Population changes through birth rates, death rates and migration; the population pyramid shows the age structure, and a changing population affects the economy.

A country's population is always changing. Understanding why helps governments plan schools, hospitals, housing and jobs.

Why this matters Whether a population is young and growing fast or older and shrinking changes almost everything: how many workers there are, how much tax is collected, and how much is spent on the young and old.

What changes a population

Population change depends on three things:

the birth rate: births per 1,000 people per year;
the death rate: deaths per 1,000 people per year;
net migration: people moving in minus people moving out.

The natural increase is the birth rate minus the death rate. If births exceed deaths, the population grows naturally.

Why birth and death rates change

Birth rates tend to fall as countries develop, because of better education (especially for girls), family planning, lower infant mortality and the higher cost of raising children in cities. Death rates fall with better healthcare, clean water, food supply and sanitation.

The population pyramid

A population pyramid is a diagram showing the number of males and females in each age group. Its shape tells a story:

a wide base means many children and a high birth rate, common in a fast-growing country;
narrower, more even bars mean an ageing population with a low birth rate.

A wide base means many children and a high birth rate; narrower, more even bars mean an older, slower-growing population.

Effects of a changing population

A young, growing population needs more schools and, later, many new jobs; it also has a high dependency ratio of children to workers. An ageing population needs more healthcare and pensions, and fewer workers must support more retired people. Both extremes place pressure on an economy, so governments try to plan ahead and, where helpful, encourage a balanced age structure. Wise planning treats a growing population as a source of talent, not only a cost.

Common exam mistake: assuming a population pyramid with a wide base is automatically "bad". A young, fast-growing population brings challenges (many mouths to feed, school places needed) AND opportunities (a future large workforce) - avoid one-sided answers.

Exam technique: when describing a population pyramid, use the correct vocabulary for its SHAPE - "wide base" for high birth rates, "narrowing with age" for typical survival, or "top-heavy/rectangular" for an ageing population - precise shape description is what earns the mark.

Put these stages of a country's population change in order as it develops:

High birth rates and high death rates - population fairly stable
Death rates fall first (better healthcare, sanitation) while birth rates stay high - population grows fast
Birth rates begin to fall too (education, family planning) - growth slows
Both birth and death rates are low - population growth stabilises

Migration also shapes a population. People may move within a country, often from the countryside to cities, or between countries in search of work or safety. Inward migration can add workers and skills, while outward migration can ease crowding but may remove talented young people. Because every population is different, governments study these trends carefully before deciding how many schools, homes and hospitals to build.