Economic Development

Measuring living standards: real GDP per head

Economic growth and economic development sound similar but ask different questions: growth asks whether output rose; development asks whether that extra output actually made people’s lives better.

Single and composite indicators

Living standards can be measured with a single indicator — one figure, such as real GDP per head, the number of doctors per 1000 people, or the infant mortality rate — or with a composite indicator, which combines several single indicators into one score. Real GDP per head is the most widely used single indicator because national income data is collected by almost every country, making comparisons straightforward.

Real GDP per head = Real GDP ÷ Population — measured in average income per person, inflation-adjusted.

Worked example: comparing two countries

Country A has a real GDP of $450 billion and a population of 90 million. Country B has a real GDP of $60 billion and a population of 20 million. Which country has the higher real GDP per head?

Step 1. Country A: $450bn ÷ 90m = $5000 per head. Step 2. Country B: $60bn ÷ 20m = $3000 per head. Step 3. Country A has the larger total GDP, but comparing totals alone would be misleading — dividing by population is what makes the two countries comparable. Country A: $5000 per head.

Why real GDP per head is used — and where it falls short

Dividing by population and adjusting for inflation lets real GDP per head compare living standards both between countries of very different sizes and within one country over time. But it is still only an average: it says nothing about how that income is shared out, ignores unpaid and informal work such as subsistence farming or care in the home, and captures none of the things people value that are not bought and sold, such as leisure time, safety or a clean environment.

The human development index (HDI)

If GDP per head’s main weakness is that it only measures income, the natural fix is a measure that adds the two things income alone leaves out: health and education.

The three components of the HDI

The HDI combines three equally-weighted components: health, measured by life expectancy at birth; education, measured by the average years of schooling adults have completed and the years a child starting school today can expect to receive; and income, measured by real Gross National Income (GNI) per head at purchasing power parity, which adjusts for differences in the cost of living between countries. Each country’s score on the three components is combined into one HDI figure between 0 and 1, where a score closer to 1 indicates a higher level of human development.

Reading an HDI score

HDI scores are grouped into four bands: below 0.550 is low human development; 0.550 to 0.699 is medium; 0.700 to 0.799 is high; and 0.800 or above is very high human development. A country can move between these groups over time as any of its three components improves.

Comparing living standards & income distribution

Two countries can have the same average income and still look very different, once you ask who actually receives it.

Why living standards differ between countries

Countries with higher income per head can fund better healthcare, education and infrastructure, and a larger stock of natural resources gives some countries export income that others lack. Political stability attracts investment and lets governments plan long term, while technology and innovation raise productivity and create higher-paying jobs. Each of these factors is developed further in §5.4, where they are used together to explain the overall gap in development between countries.

Why income distribution differs within a country

Within the same country, income inequality mainly comes from five sources. Differences in education and skills mean specialist or in-demand workers earn far more than unskilled workers. Inherited wealth lets some households earn rental, dividend or investment income without working, independent of their own productivity. Government tax and welfare policy narrows the gap where taxation is progressive and benefits are generous, and widens it where they are not. Employment opportunities are usually richer in urban areas than rural ones, so where a household lives affects what it can earn. Finally, discrimination by gender, ethnicity, age or disability can restrict access to higher-paying jobs regardless of skill.

Worked example: reading a relationship from data

Country W has GDP per head of $1200 and 40% of children complete secondary education. Country X has $2600 and 58%. Country Y has $6100 and 81%. Country Z has $1900 and 70%. Describe the relationship shown.

Step 1. State the expected relationship: higher GDP per head is generally associated with a higher percentage of children completing secondary education. Step 2. Give supporting evidence: W has both the lowest GDP per head and the lowest completion rate; Y has both the highest. Step 3. Note the exception: Z has a lower GDP per head than X but a higher completion rate, so the relationship is not perfect — a government’s spending priorities, not just its income, also matter. Positive relationship, with one exception (Z).

Poverty: definitions & causes

Poverty is defined two different ways, and which one applies changes both how severe it looks and what would actually fix it.

Absolute and relative poverty

A person in absolute poverty cannot meet their basic physical needs, regardless of how their income compares to anyone else’s; international organisations often set this as a fixed income threshold, such as a small number of dollars per day. A person in relative poverty may be able to meet basic needs but has an income far below what is typical in their own country — for example, a government might define relative poverty as household income below 60% of the national median. Absolute poverty is more common in lower-income countries; relative poverty is the main form of poverty discussed in higher-income countries, since it can persist even as average incomes rise.

Causes of poverty

Unemployment removes a household’s main source of income, especially where state benefits are limited. Low wages leave even employed (“working poor”) households unable to cover rent, food and healthcare. Illness or disability can prevent a person from working while simultaneously raising their costs, particularly where healthcare is expensive. Age affects both ends of life: the elderly may have no income beyond a pension, and children in low-income households are dependents with no income of their own. Environmental factors, such as drought, flooding or poor land quality, can destroy crops and the income of entire farming communities at once.

A self-reinforcing cycle

These causes often reinforce one another. Low income makes education and healthcare harder to afford; poorer education and health in turn reduce productivity and future earning potential; and lower earning potential perpetuates the low income the cycle started with. A policy that successfully intervenes at any point in this cycle — not only by raising income directly — can help break it, which is exactly why the policies on the next page target education and healthcare alongside income itself.

Policies to alleviate poverty

Six policies recur in Cambridge questions on poverty, and they split naturally into two groups: those that raise incomes directly, and those that raise them indirectly by investing in people.

The six policies

Governments use: promoting economic growth, so that rising national income eventually raises wages across the economy; improved education, a supply-side policy that raises future productivity and earning potential; improved healthcare provision, which keeps workers productive and reduces the income lost to illness; more generous state benefits, such as unemployment and disability payments, aimed directly at those with the lowest incomes; progressive taxation, which funds the spending above while narrowing the gap between high and low earners; and a national minimum wage, which raises pay directly for the lowest-paid workers in employment.

Worked example: how progressive a tax actually is

Under a progressive tax system, a worker earning $20,000 pays $2,000 in tax, and a worker earning $80,000 pays $16,000 in tax. Compare the average rate of tax paid by each worker.

Step 1. Lower earner’s average tax rate = $2,000 ÷ $20,000 × 100 = 10%. Step 2. Higher earner’s average tax rate = $16,000 ÷ $80,000 × 100 = 20%. Step 3. The higher earner pays tax at double the rate of the lower earner, even though both pay the same proportional formula — this rising average rate is what makes a tax progressive, not simply the larger dollar amount paid. 10% vs 20% — progressive.

Direct versus indirect routes out of poverty

State benefits, progressive taxation and the minimum wage work directly and quickly, by changing a household’s income this year. Economic growth, education and healthcare work indirectly and more slowly, by raising the productivity and earning potential that determine income in future years. A government facing urgent poverty usually needs both: direct policy to relieve hardship now, and indirect policy to prevent it recurring.

Factors affecting population growth

A country’s population changes for exactly three reasons, and all three are tested as a set: a question naming only one is unusual.

The three drivers of population change

A population grows when the birth rate exceeds the death rate, when net migration is positive, or both.

Net migration = Immigration − Emigration — measured in positive if net inward · negative if net outward.

Worked example: net migration

In one year, 340,000 people immigrated into a country and 505,000 people emigrated from it. Calculate net migration and state its effect on population.

Step 1. Net migration = 340,000 − 505,000. Step 2. Net migration = −165,000. Step 3. The figure is negative, so more people left the country than entered it — net migration reduced the population that year, other things being equal. −165,000 (net outward).

Why these rates vary between countries

Birth rates tend to be higher where access to contraception and education is limited, where children support household income (for example in farming), or where infant mortality is high enough that families have more children as a safeguard; birth rates fall as education, career opportunities for women, and the cost of raising children rise. Death rates are higher where healthcare, sanitation and nutrition are poor, and fall as these improve. Net migration responds to the gap between countries in wages, job opportunities, safety and political stability — people move toward better opportunities and away from conflict, poverty or natural disaster.

Population structure & its effects

A country is never simply “overpopulated” in absolute terms — it is overpopulated only relative to what its own resources and technology can support.

Over- and underpopulation

Overpopulation occurs when a country has more people than its resources and technology can support, raising unemployment, pressure on housing and public services, and pollution. Underpopulation occurs when resources are under-used relative to the population available to work them, leading to a shortage of workers, a narrower tax base, and wasted productive capacity. At the optimum population, resources and population are balanced and output per head is at its highest.

Why population structure differs, and what it does to an economy

A country with a high birth rate and falling death rate develops an expanding population structure — a wide base of children and a smaller share of elderly dependents. A country with a low birth rate and longer life expectancy develops an ageing structure instead — a shrinking base and a growing share of elderly dependents. Migration can distort either shape further, typically by adding working-age adults.

An expanding population raises spending on schools and child-related services now, in exchange for a larger future labour force. An ageing population raises pension and healthcare spending, shrinks the labour force, and can force governments to raise taxes, encourage immigration, or raise the retirement age to manage a rising dependency ratio — the number of dependents per worker.

Differences in development between countries

No single factor explains why one country develops faster than another — examiners expect several, applied together, not one cause treated as the whole story.

Eight sources of difference

Countries differ in: income — a higher GDP per head funds better services, though it can mask internal inequality; productivity — more productive workers earn higher wages and raise living standards; population growth — rapid growth spreads government spending across more people; sector size — economies weighted toward higher-value secondary and tertiary output tend to pay higher wages than those still concentrated in primary production; saving and investment — higher saving funds the investment that raises future capital and output; education and healthcare — both raise the productivity of the workforce directly; and natural resources — an abundance of resources such as oil, minerals or fertile land can fund exports and growth, though it does not guarantee development reaches the wider population.

Worked example: applying the eight factors

Country P has a large manufacturing sector, high savings, and strong secondary education. Country Q relies mainly on subsistence farming, has low savings, and limited access to secondary education. Analyse two reasons why Country P is likely to be more developed.

Step 1. Sector size: P’s manufacturing (secondary) output typically pays higher wages than Q’s primary-sector farming, raising average income. Step 2. Saving and investment: P’s higher savings fund more investment in capital, raising future productivity and output; Q’s low savings limit this. Step 3. Education reinforces both effects: P’s stronger secondary education raises the skills needed for manufacturing work, while Q’s limited access constrains workers to lower-productivity, lower-paid activity. Sector size + saving/investment, reinforced by education.