Model essay (a): why GDP per head can mislead

What this lesson teaches

• I can read real GDP, GNI, per-capita figures, unemployment rate, CPI, balance of trade, HDI and the Gini coefficient.

  Syllabus 9570, 3.2.1(c). Standard of Living and Macroeconomics Indicators: Macroeconomic indicators; Indicators of economic performance include real Gross Domestic Product (GDP) or Gross National Income (GNI), real GDP or GNI per capita, unemployment rate, Consumer Price Index (CPI) and balance of trade; Human Development Index (HDI) as an indicator to reflect standard of living; Gini coefficient as an indicator to reflect income distribution

• I can compare living standards over time and between countries, and say where the comparison is weak.

  Syllabus 9570, 3.2.1(d). Standard of Living and Macroeconomics Indicators: Comparison of living standards over time and over space (between economies)

Make a guess

Country A's income per head in US dollars is double country B's. Can you say people in A are twice as well off?

1. Yes, as long as both figures are in US dollars.
2. Yes, because income per head measures living standards.
3. No. Prices, sharing, and non-income factors differ.

The answer to part (a)

Introduction

Real gross domestic product (GDP) per capita is the value of a country's output per person, adjusted for inflation. It is widely used as a guide to material living standards, because more output per person usually means more goods and services each. But it can mislead when comparing countries, for four reasons. These are differences in prices, how income is shared, what GDP leaves out, and the gap between GDP and the income residents actually receive.

Paragraph 2: prices and currencies

To compare countries, GDP must be converted into one currency, usually US dollars. At market exchange rates, this ignores differences in the cost of living. A haircut, a meal or a month's rent costs far less in a lower-income country than in Singapore, so a dollar buys more there. Comparing at market exchange rates understates living standards in low-price countries. Economists therefore use purchasing power parity (PPP), which adjusts for price differences and shows what incomes can actually buy.

Paragraph 3: an average hides how income is shared

Real GDP per capita is an average. Two countries can have the same average but share income very differently. In Figure 1, Country A's Lorenz curve bows further from the line of equality than Country B's. So in Country A the poorest households receive a much smaller share of income. A typical household in A is worse off than one in B, even though the averages are equal. Median household income and the Gini coefficient show distribution better.

Paragraph 4: what GDP leaves out

GDP counts only goods and services that are bought and sold, so it misses a lot. Unpaid work, such as caring for children or elderly parents at home, is left out, and its importance differs between countries. Work in the shadow economy, which is hidden from the authorities, is also missed. GDP says nothing about non-material living standards: health, leisure time, safety and the quality of the environment. A country with high GDP per capita but long working hours and polluted air may have lower living standards than its GDP suggests.

Paragraph 5: GDP is not residents' income

GDP measures output produced within a country, whoever owns the firms. In Singapore, many firms are foreign-owned and send profits home, so the income available to residents is lower than GDP suggests. Gross national income (GNI) per capita, which adds income earned abroad and subtracts income paid to foreigners, is a better guide to residents' income. Comparing GDP per capita can overstate living standards in economies with heavy foreign ownership.

Conclusion

Real GDP per capita may mislead for four reasons. Exchange rates ignore price differences, an average hides inequality, GDP leaves out unpaid work and non-material living standards, and output is not the same as residents' income. A fair comparison uses PPP figures, median income and the Gini coefficient, GNI, and indicators such as the Human Development Index.

Margin notes: how each paragraph scores

Introduction

Defines the indicator, says why it is used, and previews four weaknesses.

Paragraph 2

Explains why market exchange rates mislead and how PPP corrects it. Each weakness comes with its fix, which marks look for.

Paragraph 3

Uses Figure 1 to show distribution, then names the better indicators. The diagram turns a list point into analysis.

Paragraph 4

Covers unpaid work, the shadow economy and non-material living standards, explaining why each matters for comparisons.

Paragraph 5

GDP against GNI, with Singapore as the example. This point is often missed and helps reach the top of L3.

Conclusion

Summarises the weaknesses and the fuller set of indicators. No evaluation marks are available for a 10-mark part.

Overall: L3, 9 or 10 marks

Several weaknesses explained, each with why it matters and how to correct it, using a diagram and context. A list of limitations without explanation would stay at L1 or L2.

Worked example: A 3-minute plan

Four weaknesses, each with its correction.

1. Intro: real GDP per capita is average output per person; a guide to material living standards.
2. Prices and currencies: use PPP.
3. Distribution: an average hides inequality (Figure 1); use median income, Gini.
4. Left out: non-material living standards, unpaid work, the shadow economy.
5. GDP against GNI: profits sent abroad; use GNI per capita.

Watch out for this

Converting GDP per capita into US dollars at market exchange rates makes countries fully comparable.

Market exchange rates ignore differences in prices. A dollar buys more in some countries than others, so purchasing power parity (PPP) figures are needed.

Check your understanding

Why can GNI per capita be a better guide than GDP per capita for Singapore's residents?

1. GNI counts unpaid work at home, which GDP leaves out of the total.
2. GNI is adjusted for differences in prices between countries, but GDP is not.
3. Much of the income from production in Singapore goes to foreign owners.