Question

Explain the identity of output, income and expenditure in national income accounting.

Answer 1

The identity of output, income, and expenditure in national income accounting refers to the fundamental principle that the total value of goods and services produced in an economy (output) is equal to the income earned from that production (income), which is also equal to the total expenditure on those goods and services (expenditure). This identity is expressed as:

National Product ≡ Income Generated ≡ Total Expenditure

If you read the three bars as then “=” means that the three magnitudes are equal by definition.

This means that all the goods and services produced in an economy generate an equal amount of income for the factors of production, such as wages for labour, rent for land, interest for capital, and profits for entrepreneurs. The same income is spent by households, businesses, and the government to purchase goods and services, which forms total expenditure. Thus, the output value, income, and purchase cost are all equal in theory.

Thus, national income can be measured by the value of output, income generated, or expenditure incurred, and all three are theoretically identical. However, in practice, the methods use different data, so a statistical discrepancy is added to reconcile the estimates.