AQA A-Level Economics · Revision notes

4.2.1.4 Uses of National Income Data

National income data, above all real GDP per capita, is the most widely used guide to living standards. This topic covers how the data is used to judge changes in living standards over time and differences between countries, why purchasing power parity (PPP) exchange rates are needed for international comparisons, and the limitations that mean GDP is an imperfect guide.

Using national income data over time

GDP is the total value of goods and services produced in an economy over a period of time. To judge whether living standards in one country are rising, two adjustments matter.

• Real versus nominal. Real is adjusted for inflation; nominal is measured at the prices of the day.
• Total versus per capita. Total GDP is the whole economy's output. GDP per capita divides that by the population, and it is the better guide to the average person's material standard of living. An economy can grow 2% while GDP per capita falls, if the population grows faster.

Key idea: The word real is doing essential work. Nominal GDP can rise simply because prices rose, without a single extra good being produced. Real GDP strips inflation out, so a rise means the economy genuinely produced more.

Other measures of national income

• GNI (Gross National Income) measures income earned by a country's residents wherever in the world it was earned, rather than income generated inside the country's borders.
• GNP is the same idea expressed as output.

The gap between GDP and GNI matters in practice. Ireland's GDP is inflated by the profits of multinational firms based there, much of which flows abroad; its GNI is markedly lower and describes Irish living standards far better. The distinction is not a technicality: for some economies, GDP and GNI describe noticeably different things.

Comparing countries fairly

Converting one country's GDP into another's currency at the market exchange rate distorts the comparison, because exchange rates move for reasons unconnected to living costs, and non-traded goods like haircuts and rent are far cheaper in poorer countries.

Purchasing power parity (PPP) adjusts the figures so that a given sum buys a comparable basket of goods in each country.

Key distinction: Comparisons of living standards across countries should always use PPP-adjusted figures. Comparisons over time within one country should always use real figures.

Why GDP is an imperfect guide to living standards

• It ignores distribution. Rising GDP per capita says nothing about who received the extra income.
• It misses unrecorded activity. The informal economy, cash work and unpaid household labour go uncounted, and both are proportionally larger in developing economies.
• It ignores what is produced. Output of weapons, prisons and clean-up after a flood all count the same as output of hospitals and food.
• It ignores external costs. Growth that pollutes a river adds to GDP twice: once for the output, and again for the clean-up.
• It ignores leisure and working conditions. An economy where people work 60-hour weeks may out-produce one where they work 35, without anyone being better off.
• Quality changes are hard to capture. A £500 phone today is a vastly better product than a £500 phone in 2010.

Some of these limitations matter most when comparing over time, such as changes in product quality. Others matter most when comparing countries, such as differences in the size of the informal economy, in working hours and in how evenly income is shared.

Measuring wellbeing instead

Because of those gaps, the ONS publishes measures of national wellbeing, which include life satisfaction, health, relationships and the environment alongside income.

The interesting economics here is the Easterlin paradox: within a country at a point in time, richer people report higher life satisfaction, but as a country grows richer over decades, average reported happiness rises far less than income does. Whether income raises wellbeing appears to depend partly on income relative to others, not on absolute income alone — so growth does not translate automatically into a happier population.

Key terms

Common mistakes

• Comparing nominal figures over time, or market-exchange-rate figures across countries.
• Treating GDP per capita as a measure of the typical person. It is a mean, and a mean is pulled upwards by high incomes.
• Treating GDP's limitations as universal. Which limitation matters most depends on the economy: unrecorded activity dominates in some, environmental cost or inequality in others.

How this has been examined

In the AQA papers indexed on this site, this topic has appeared in five formats:

• 15-mark "Explain" essay — asked once (2025)
• 10-mark "To what extent" data response — asked once (2020)
• 4-mark "Explain" data response — asked 3 times across 3 series (2017 to 2024)
• 2-mark calculation — asked twice across 2 series (2019 to 2024)
• 1-mark multiple choice — asked 5 times across 5 series (2019 to 2025)

Where this goes next

The indicators themselves are set out in 4.2.1.2 Macroeconomic indicators, and the price indices used to turn nominal figures into real ones in 4.2.1.3 Uses of index numbers. What national income measures, and the difference between nominal and real income, are covered in 4.2.2.1 The circular flow of income. The limits of GDP as a guide to living standards reappear in 4.2.6.5 Economic growth and development.