4.1 - National Income Statistics
The concept of national income and its statistics
National income represents the total value of goods and services produced in a country over a specific period. It reflects the economy's overall output, which generates income that people spend on that output. As a result, total output equals total income and total expenditure in the economy.
National income statistics provide measures of a country's economic activity, focusing on output, income, and expenditure. Governments use these statistics to evaluate economic performance, considering an economy successful if output grows steadily without causing issues like inflation or environmental harm.
International organisations, such as the United Nations, rely on national income statistics to compare economic performance across countries. Higher output can lead to improved living standards, prompting governments to implement policies when growth falls short of potential. Economists analyse both the level of output and its growth rate to understand economic health.
Key measures including GDP and GNI
Several key measures capture different aspects of national income, each providing insights into economic activity.
Gross domestic product (GDP)
Gross domestic product (GDP) is the most common measure of national income. It calculates the total value of all goods and services produced within a country's borders over a set period, regardless of who owns the production factors.
Gross national income (GNI)
Gross national income (GNI) measures the total income earned by a country's residents and businesses, including earnings from abroad. It forms part of the United Nations Human Development Index.
GNI includes:
- Net property income from abroad - Profits and dividends earned overseas minus those sent out.
- Compensation of employees - Wages earned by residents working abroad for short periods.
- Net taxes less subsidies on products - Adjustments for government interventions in production.
Gross national disposable income
This measure builds on GNI by including net remittances, such as money sent home by workers abroad minus outflows from foreign workers in the country.
Differences between GDP and GNI
In some countries, GDP exceeds GNI when foreign multinational companies (MNCs) produce significant output but send profits abroad. Conversely, GNI can surpass GDP in countries with net inflows from overseas investments or citizens working abroad.
Methods of calculating GDP
GDP can be calculated using three approaches, each reflecting the circular flow of income where money moves between households and firms. All methods should produce the same result if data is accurate.
The output method
This approach sums the value of production across all industries. To avoid double counting, it focuses on final goods and services or calculates value added at each stage.
Value added is the difference between a firm's sales revenue and the cost of its inputs. For example, a furniture maker buying wood for £200,000 and selling finished items for £320,000 adds £120,000 to GDP.
The income method
This method totals earnings from factors of production, including wages, rent, interest, and profits. It excludes transfer payments like welfare benefits or subsidies, as these do not represent new production.
The expenditure method
This sums spending on final goods and services, including consumer spending, government spending, investment, changes in inventories, and net exports (exports minus imports). Like the income method, it excludes transfer payments.
Adjustments in national income measurement
National income figures require adjustments to reflect accurate economic values, accounting for factors like prices, investment, and depreciation.
Market prices and basic prices
GDP and GNI can be measured at market prices or basic prices:
- Market prices - These include taxes added to products and exclude subsidies, representing what consumers actually pay.
- Basic prices (also known as factor cost) - These exclude taxes and include subsidies, showing the income received by factors of production without government adjustments.
For instance, a product costing £12 with a £4 tax has a market price of £12 but a basic price of £8. A product costing £18 with a £2 subsidy has a basic price of £18 but a market price of £16.
Gross and net investment
Gross investment covers all spending on capital goods, including replacements and new additions. Net investment subtracts depreciation (the wear and tear on existing capital) from gross investment.
Net domestic product (NDP) and net national income (NNI)
These measures use net investment instead of gross. NDP is GDP minus depreciation, while NNI is GNI minus depreciation. Positive net investment signals growing production capacity, zero indicates stability, and negative shows decline.
Comparing economic growth between countries
When assessing economic growth, both absolute changes and percentage changes in output are essential, as they provide different perspectives.
Absolute change measures the actual increase in output value, while percentage change accounts for the starting base.
For example, if Country X's output rises from $500 billion to $530 billion ($30 billion absolute increase, 6% growth), and Country Y's rises from $9 trillion to $9.36 trillion ($0.36 trillion absolute increase, 4% growth), Country Y has a larger absolute increase but slower percentage growth due to its bigger economy.
Factors to consider in comparisons:
- Base size - Larger economies may show bigger absolute gains but smaller percentage increases.
- Sustained growth - Steady percentage growth indicates long-term success.
- Policy implications - Governments use these comparisons to introduce measures for boosting growth when it lags behind potential or competitors.
Worked example - Calculating value added
A toy manufacturer buys components for £180,000 and sells the finished toys for £280,000. Calculate the value added by the manufacturer.
Step 1: Identify the values
- Cost of inputs = £180,000
- Sales revenue = £280,000
Step 2: Apply the value added formula
Step 3: Calculate the value added
Worked example - Comparing absolute and percentage changes in output
In one year, Country P's output increases from $300 billion to $315 billion, while Country Q's increases from $7 trillion to $7.28 trillion. Calculate the absolute and percentage changes for each country.
Step 1: Identify the values
- Country P: Initial output = $300 billion, New output = $315 billion
- Country Q: Initial output = $7 trillion, New output = $7.28 trillion
Step 2: Calculate absolute changes
- Country P: $315 billion - $300 billion = $15 billion
- Country Q: $7.28 trillion - $7 trillion = $0.28 trillion
Step 3: Calculate percentage changes
- Country P:
- Country Q: