8.1 - The Circular Flow of Income
The components of the circular flow of income
An economy consists of two main groups: firms and households. Firms create goods and services, which form the national output. Households supply the factors of production—labour, land, and capital—that firms need to generate this output.
The payments firms make to households for these factors represent the national income. Households then use this income to buy goods and services from firms, creating national expenditure. This process forms a continuous loop where national output equals national income and national expenditure.
Formula linking national output, income, and expenditure
Types of flows in the circular flow
The circular flow involves two distinct types of exchanges between households and firms.
Physical flows
These represent the movement of real resources and outputs:
- Goods and services produced by firms and purchased by households.
- Factors of production (labour, land, capital) provided by households to firms.
Monetary flows
These involve the payments for physical flows:
- Income paid by firms to households for factors of production.
- Expenditure by households on goods and services from firms.
Injections and withdrawals in the circular flow
The basic circular flow assumes constant output if spending matches earnings. However, external factors can alter this by adding or removing money from the loop.
Injections
Injections increase the flow of money and go directly to firms:
- Exports - Sales of goods and services to foreign buyers, bringing in additional revenue.
- Investment - Spending by firms on new capital, such as machinery or buildings.
- Government spending - Public expenditure on goods, services, or infrastructure.
Withdrawals
Withdrawals reduce the flow of money and can be made by households or firms:
- Imports - Purchases of foreign goods and services, sending money abroad.
- Savings - Money set aside by households or firms, not spent on current consumption.
- Taxes - Payments to the government, reducing available income for spending.
If households spend all their income and firms reinvest all revenues, the flow remains stable. However, injections and withdrawals cause changes in national output and income.
Economic equilibrium in the circular flow
Economic equilibrium occurs when the economy's output, income, and expenditure are balanced, leading to stable conditions.
Conditions for equilibrium
- Equilibrium exists if injections equal withdrawals, maintaining a steady circular flow.
- When injections exceed withdrawals, expenditure surpasses output, prompting firms to increase production to meet demand.
- When withdrawals exceed injections, output exceeds expenditure, leading firms to decrease production to avoid excess stock.
These imbalances drive adjustments in the economy until equilibrium is restored.
The multiplier effect and factors affecting it
The multiplier effect explains how an initial injection into the economy leads to a larger overall increase in national income, output, and expenditure.
When an injection occurs, such as government investment in infrastructure, it pays households for factors of production, boosting their income. Households spend part of this income on goods and services, increasing firm revenues and encouraging more production. This creates further income, with the process repeating in rounds.
However, each round sees some money withdrawn through savings, taxes, or imports, gradually reducing the effect until it fades.
Factors influencing the size of the multiplier
The multiplier's magnitude depends on the rate of leakages (withdrawals) from the circular flow:
- High leakages - Large withdrawals (e.g., high savings rates, taxes, or imports) cause money to exit quickly, resulting in a smaller multiplier.
- Low leakages - Smaller withdrawals allow more money to circulate, leading to a larger multiplier effect.
The difference between wealth and income
Income and wealth are related but distinct concepts in economics.
Income
Income is a flow of money received over time, such as wages or profits. It circulates in the economy through spending and production.
Wealth
Wealth is a stock of accumulated assets, including savings, property, or other valuables owned by individuals or firms. Unlike income, wealth is not actively circulating but represents stored resources that could enter the flow later.
Although high-income individuals often build greater wealth through savings and asset purchases, the two are not identical.