2.2 - Measuring Economic Growth
Macroeconomic indicators for measuring economic performance
Macroeconomics examines the overall economy, including the activities of governments, all businesses, individuals, and international trade. Governments rely on key indicators to assess how well the economy is performing and to guide policy decisions.
The main macroeconomic indicators
- Rate of economic growth - Measures the increase in a country's output of goods and services over time.
- Rate of inflation - Tracks the general rise in prices across the economy.
- Level of unemployment - Indicates the proportion of the workforce without jobs but actively seeking employment.
- State of the balance of payments - Shows the difference between a country's earnings from exports and its spending on imports, including other international transactions.
GDP and how economic growth is measured
Economic growth refers to the expansion of a country's production of goods and services over time. It is primarily measured using gross domestic product (GDP), which represents the total value of everything produced within a country's borders in a given period.
Ways to measure national output
National output can be assessed in terms of quantity or monetary value:
- By volume - Counts the total number of goods and services produced in a year.
- By value - Calculates the monetary worth (in £billions) of all goods and services produced in a year, which is the most common method and forms the basis of GDP.
GDP can also be determined by summing up total national expenditure (spending) or total national income (earnings). In theory, these three approaches—output, expenditure, and income—should equal each other due to the circular flow of money in the economy.
Patterns in economic growth
- The rate of economic growth describes how quickly national output is increasing, often varying from year to year.
- Extended periods of rapid growth are known as booms.
- A recession occurs when there is negative growth for two consecutive quarters.
- A prolonged recession is called a slump.
- An economic depression is a severe, long-lasting downturn worse than a typical recession.
Worked example - Calculating percentage change in GDP
In 2022, a country's GDP was £3,500 billion. In 2023, it increased to £3,675 billion. Calculate the percentage change in GDP.
Step 1: Identify the values
- Original GDP = £3,500 billion
- Change in GDP = £3,675 billion - £3,500 billion = £175 billion
Step 2: Apply the formula
Step 3: Perform the calculation
Nominal and real GDP
Not all increases in GDP reflect genuine growth, as rising prices can inflate the figures. Distinguishing between nominal and real GDP helps provide a more accurate picture of economic progress.
Differences between nominal and real GDP
- Nominal GDP - The raw GDP figure without adjustments for inflation, which can overstate growth if prices have risen.
- Real GDP - Adjusts nominal GDP to remove inflation effects, showing the true change in output volume.
For example, if nominal GDP grows by 7% but inflation is 3%, real GDP has increased by approximately 4%.
GDP per capita and standard of living
GDP per capita provides insight into average economic well-being by dividing total output by population size. It is often used alongside other measures to compare living standards across countries.
Formula for GDP per capita
A higher GDP per capita generally suggests a better standard of living, as it implies more goods and services available per person.
Related measures for comparing living standards
- Gross national income (GNI) - GDP plus net income from abroad (e.g., investments) minus income earned by foreign entities domestically; GNI per capita accounts for international earnings.
- Gross national product (GNP) - The total output produced by a country's citizens, regardless of location; GNP per capita focuses on national productivity.
Purchasing power parity
When comparing living standards internationally, currency exchange rates may not accurately reflect what money can buy in different countries. Purchasing power parity (PPP) addresses this by adjusting for differences in the cost of living.
How purchasing power parity works
- PPP measures the real buying power of a currency—what goods and services it can actually purchase.
- In less developed countries, a given amount of money often buys more than in advanced economies due to lower prices.
- GDP figures are adjusted using PPP to enable fair comparisons, typically expressed in US dollars.
- This adjustment accounts for variations in living costs, providing a clearer view of relative economic well-being.
Limitations of GDP comparisons
While GDP and related measures are useful, they have drawbacks when used to compare economic performance or living standards between countries or over time.
Factors not captured by GDP
- Hidden economy - Unofficial or unreported activities, such as informal work, are excluded from official figures.
- Public spending variations - Differences in government-provided services (e.g., free healthcare or benefits) affect actual living standards but are not reflected in GDP.
- Income inequality - Two countries with the same GDP per capita might have vastly different wealth distributions, impacting overall quality of life.
- Other quality-of-life aspects - Elements like longer working hours, poor working conditions, environmental harm, or climate-related expenses (e.g., heating in cold regions) are overlooked.
These limitations mean GDP should be considered alongside other data for a complete picture.
Using index numbers
Index numbers simplify the tracking of changes in economic data, such as GDP, by showing percentage shifts relative to a base year.
How index numbers are calculated and interpreted
- A base year is assigned an index of 100.
- Subsequent values are expressed as percentages of the base: above 100 indicates growth, below 100 shows decline.
- For example, if real GDP rises by 7% from the base year, the index becomes 107; a 3% fall would make it 97.
- An index of 109 in year 6 means a 9% increase since the base year.
Worked example - Calculating an index number for GDP
A country's real GDP in the base year (2020) is indexed at 100. In 2021, real GDP increases by 8%. In 2022, it decreases by 2% from 2021. Calculate the index numbers for 2021 and 2022.
Step 1: Identify the values
- Base index (2020) = 100
- Change in 2021 = +8%
- Change in 2022 = -2% from 2021
Step 2: Calculate index for 2021
Index for 2021 = 100 + (100 × 0.08) = 108
Step 3: Calculate index for 2022
Index for 2022 = 108 - (108 × 0.02) = 105.84 (or approximately 106)