Circular Flow of Income and National Income Accounting

Meaning of National Income

National income is the total market value of all final goods and services produced in a country in a year.
It is a monetary measure adjusted for price changes to accurately reflect physical output.
To avoid double counting, only the market value of final goods is included, excluding intermediate goods.
National income represents the total value of production, receipts, and expenditure.
Every expenditure is also a receipt, leading to a threefold identity: value received = value paid = value of goods and services produced and sold.

In an economy with households and firms, firms produce goods using factors of production.
Factor payments (wages, rents, interest, and profits) equal the sales value of net production.
Income flows from firms to households in exchange for productive services and returns to firms as household expenditure on goods.
National Income = National Product = National Expenditure.
Three measures of national income:
- Sum of values of all final goods and services produced.
- Sum of all incomes accruing to factors of production.
- Sum of consumers’ expenditure, net investment expenditure, and government expenditure.
These measures reflect production, distribution, and expenditure activities.

Money facilitates exchange and removes barter system difficulties.
Households supply economic resources to firms and receive payments in money.
Money flows are in the opposite direction to real flows of economic resources and goods/services.

Assumptions:
- Households spend all income on consumer goods (no savings).
- No investment by business firms.
Resources flow from households to firms; money flows from firms to households as factor payments (wages, rent, interest, profits).
Money flows from households to firms as consumption expenditure; goods/services flow from firms to households.
Money flows from firms to households as factor payments and returns as expenditure, creating a circular flow.
This circular flow continues indefinitely but its volume changes with economic conditions.
- Contracts during depressions (low national income).
- Expands during prosperity (high national income).

Savings reduce expenditure on goods/services, contracting money flow to firms.
Reduced receipts may lead to fewer workers hired or reduced factor payments, lowering household incomes.
Savings are a leakage from the money expenditure flow.
Financial institutions (banks, insurance companies, stock markets) channel household savings back into the expenditure stream.
Firms borrow from the financial market for investment in capital goods.
Investment expenditure brings savings back into the expenditure stream, mitigating the decrease in total spending.

Saving (withdrawal of money) must equal investment (injection of money) for a steady flow.
Planned savings must equal planned investment.
If investment falls short of savings:
- Income, output, and employment fall, contracting the money flow.
- Stocks of goods increase due to reduced consumption.
- Retailers order less, leading to reduced production and investment in capital goods.
If investment exceeds savings:
- Income, output, and employment increase, expanding the money flow.
Classical economists believed the financial market coordinates savings and investment through interest rates.
- If savings exceed investment, interest rates fall.
- If investment exceeds savings, interest rates rise.
Keynes argued that savings and investment are not always equal, leading to fluctuations in income, output, and employment.
Government intervention may be necessary to maintain stability.

In national income accounts, actual savings are always equal to actual investment in a two-sector economy without government and foreign trade.
Y \equiv C + I (Value of output = Consumption + Investment).
Unsold output increases inventories, treated as part of actual investment.
Y \equiv C + S (National income = Consumption + Savings).
C + I \equiv Y \equiv C + S
I = S

Government affects the economy through taxing, spending, and borrowing.
Government purchases goods/services, including capital goods, infrastructure, defense, education, and public health.
Government expenditure is financed through taxes, assets, or borrowing.
Tax payments flow from households and firms to the government, net of transfer payments.
Government borrowing increases the demand for credit, raising interest rates and potentially lowering private investment.
Total expenditure (E) = C + I + G
Total income (Y) = C + S + T
C + I + G = C + S + T
I + G = S + T
G – T = S – I
If G > T (budget deficit), the government borrows, potentially crowding out private investment.
- Government expenditure is treated as consumption expenditure.
National saving (S) = Private saving (Y – T – C) + Public saving (T – G).
For a steady state, private saving + public saving = investment.

Open economies interact with foreign countries through exports and imports.
Exports: Goods/services produced domestically and sold to foreigners.
Imports: Foreign-made goods/services purchased by domestic households.
Money flows:
- Spending on imports flows from domestic firms to foreign countries.
- Spending on exports flows from foreign countries to domestic firms.
Balance of trade:
- Exports = Imports (trade balance).
- Exports > Imports (trade surplus).
- Imports > Exports (trade deficit).
Interaction occurs through borrowing and lending in financial markets.
Trade surplus (X > M): net capital outflow (foreigners borrow from domestic savers).
Trade deficit (M > X): capital inflow (domestic entities borrow from abroad).
National Income = C + I + G + NX (NX = net exports, X – M).
- C + I + G + NX = C + S + T
- I + G + NX = S + T
NX = Y – (C + I + G)
- Net Exports = National Domestic Product (Y) – Aggregate Domestic Expenditure
Aggregate domestic expenditure need not be equal to aggregate domestic output in an open economy.