Why macroeconomics: aggregates, agents and the four sectors

Detail

1. Micro vs macro: two ways to look at one economy

• Microeconomics studies single economic agents. An economic agent is any person or unit that makes economic decisions.
• A consumer tries to maximise satisfaction. Satisfaction here means the benefit or pleasure they get from buying and using goods.

• A producer tries to maximise profit. Profit is revenue minus cost.

• Even a very large company is "micro". It serves only its own shareholders, not society as a whole.

• Macroeconomics studies the economy as a whole. It looks at three things:
• Aggregate output: the total production of all goods and services, for example GDP.
• General price level: the average level of all prices. When this rises, we call it inflation.

• Employment: how many people have work, and how many are unemployed.

• Aggregate means a total, or an average, over the whole economy.

Point	Microeconomics	Macroeconomics
Unit studied	One consumer, firm or market	Whole economy
Typical variable	Price of one good, output of one firm	GDP, general price level, total employment
Goal of decision-maker	Private: satisfaction or profit	Public: goals set by law or the Constitution
Example decision-maker	A household, a company	The State, RBI, SEBI

2. The "representative good" trick

• Problem: an economy makes lakhs of different goods. Each is measured in its own unit (tonnes of wheat, metres of cloth, hours of teaching). They cannot simply be added.
• Observation: outputs, prices and employment in different sectors tend to move together.
• When foodgrain output grows, industrial output usually grows too.

• When prices of some goods rise, prices of others usually rise too.

• Solution: macroeconomics imagines one representative good. This is a single imaginary commodity that stands in for all goods.

• When finer detail is needed, macro uses only a few broad groups: agriculture, industry and services. These are the same three groups India uses when it reports GVA by sector.
• How it works in practice: real accounts add different goods by turning each one into money value (quantity × price).
• Worked example: an economy makes 100 kg of rice at ₹40/kg and 10 shirts at ₹500 each.
• Aggregate output = (100 × 40) + (10 × 500) = ₹4,000 + ₹5,000 = ₹9,000.
• The ₹9,000 figure acts as the "one good" that macro studies.

3. Who makes macro decisions?

• Macro decision-makers are the State and statutory bodies. A statutory body is an organisation created by an Act of Parliament.
• RBI: set up under the RBI Act, 1934. It handles money supply and interest rates.

• SEBI: set up under the SEBI Act, 1992. It regulates the securities (stock and bond) markets.

• They pursue public goals set by law or the Constitution, such as employment, education, health and defence. They do not pursue private profit.

• Why macro is needed. There are three reasons.
• (a) Some markets do not exist. Example: no private market fully supplies national defence.
• (b) Some markets fail to reach equilibrium. Equilibrium is the point where demand equals supply. Example: in a slump, the labour market can stay stuck with high unemployment.
• (c) Society chooses social goals. Reaching them means changing what the market would produce on its own. The tools are:
  • taxes and the budget (fiscal policy)
  • money supply and interest rates (monetary policy)

4. Origins of macroeconomics

• Adam Smith, An Enquiry into the Nature and Cause of the Wealth of Nations (1776), asked what makes nations rich.

• The Physiocrats of France wrote before him. They saw land and agriculture as the source of wealth.

• The NCERT answer: wealth comes from the flow of production, not from natural endowment. Natural endowment means minerals, land and other resources a country is born with.

• Evidence: resource-rich Africa and Latin America include some of the poorest countries.
• Many prosperous nations have little natural wealth.

• Lesson: what a country produces each year (a flow) matters more than the resources it owns (a stock). This is why GDP measures a flow.

• Classical tradition: assumed full employment. This means everyone who wants work at the going wage finds it, so output stays at its maximum level.

• The Great Depression (from 1929) broke that assumption. In the USA, from 1929 to 1933:
• unemployment rose from 3% to 25%
• output fell by about 33%

• so markets did not correct themselves quickly.

• J.M. Keynes, The General Theory of Employment, Interest and Money (1936), studied the economy as a whole. Macroeconomics was born as a separate branch. (The classical-vs-Keynes debate is covered in income-determination-keynes.)

5. The capitalist economy and its limits

• A capitalist economy has three features:
• (a) Private ownership of the means of production (land, machines, factories).
• (b) Production for sale in the market, not for the producer's own use.

• (c) Wage labour: labour is bought and sold at a wage rate.

• Such economies arose only in the last 300–400 years. Strictly, only a handful of countries qualify.

• Where the framework fits poorly:
• Peasant economies: they use family labour (not wage labour), produce largely for their own use, and add little to their capital stock.

• Tribal economies: land is owned in common, not privately.

• Why this matters for India: a large share of India's output comes from household and unincorporated units. These are small businesses that are not registered as companies, such as a family shop or farm, and they do not look like "firms" in the textbook sense.

• The new GDP series now estimates the GVA of the household sector and quasi-corporations from two annual surveys: the Annual Survey of Unincorporated Sector Enterprises (ASUSE), run every year since 2021-22, and the Periodic Labour Force Survey (PLFS) [3].
• A quasi-corporation is an unincorporated business that keeps full accounts and behaves like a company.

6. The four-sector model

• The four-sector model views the economy as four groups of agents: households, firms, government and the external sector.

Sector	Definition / role	Money it receives	Money it spends
Household	One person, or a group, making joint consumption decisions	Factor incomes: wages, rent, interest, profit	Consumption, saving, taxes
Firms	Production units run on capitalist lines. The entrepreneur hires labour, capital and land, bears the risk and sells output for profit	Sales revenue	Factor payments: rent, interest, wages, profit
Government	Frames and enforces laws, delivers justice, taxes, builds infrastructure, runs schools and health services, sometimes produces goods itself	Taxes	Public spending, transfers
External sector	The rest of the world	Our exports (sales abroad), capital inflows	Our imports (purchases from abroad), capital outflows

• Factor services are the services of the four factors of production. Each factor earns its own income:
• land earns rent
• labour earns wages
• capital earns interest

• entrepreneurship earns profit

• Worked example: how a firm's revenue splits

• A firm sells output worth ₹100 (net of the cost of inputs it bought from other firms).
• It pays rent ₹10 + interest ₹15 + wages ₹50. The entrepreneur keeps profit ₹25.
• ₹10 + ₹15 + ₹50 + ₹25 = ₹100. All the value added becomes someone's factor income.

• This is why output, income and expenditure measures of national income match.

• How the sectors link up (the circular flow):

• Households supply factor services to firms, and firms pay factor incomes to households.
• Households spend that income on firms' output, so the money returns to firms.
• Leakages take money out of this loop: saving, taxes and imports.
• Injections put money back in: investment, government spending and exports.

7. Link to official national accounts

• The UN System of National Accounts (SNA) 2025 puts every resident unit into exactly one of five institutional sectors [5]:
• non-financial corporations
• financial corporations
• general government
• non-profit institutions serving households (NPISH)

• households

• Transactions with non-residents are recorded as the rest of the world [5].

• Mapping to NCERT's four sectors:
• Firms = the two corporation sectors.
• Government = general government.
• Households = households (plus NPISH).

• External sector = rest of the world.

• India's base year has moved on. On 27 February 2026, MoSPI released a new GDP series with base year 2022-23, replacing 2011-12 [2]. (NCERT/scaffold: 2011-12 base series, introduced 2015.)

• Why 2022-23: it is a recent "normal" year after COVID, with good data across all sectors [2][3].
• MoSPI aims to revise the base year every five years [2].
• The new series makes greater use of GST data [3].

• Back-series data (older years recalculated on the new base) is expected by December 2026 [2].

• Latest aggregates (new series):

• Real GDP growth: 7.6% (2025-26). Real GDP is output valued at base-year prices, so it removes the effect of inflation [2].
• Nominal GDP growth: 8.6% (2025-26). Nominal GDP is output valued at current prices [2].
• Nominal GDP level: ₹345.47 lakh crore (2025-26), up from ₹318.07 lakh crore (2024-25) [4].

Prelims Hooks

• A large company is still studied in microeconomics, because it serves only its own shareholders.
• Macro uses one "representative good" because outputs, prices and employment in different units tend to move together.
• The three features of a capitalist economy are private ownership of the means of production, production for the market, and wage labour.
• Wealth of Nations: Adam Smith, 1776. The Physiocrats (France) wrote before him.
• General Theory of Employment, Interest and Money: Keynes, 1936. This marks the birth of macroeconomics.
• USA, 1929–33: unemployment 3% → 25%, output fell about 33% (NCERT).
• Four sectors: households, firms, government, external. The entrepreneur bears the risk and keeps the profit.
• Trap: RBI and SEBI are statutory bodies (created by Acts), not constitutional bodies.
• India's current national accounts base year is 2022-23, released 27 February 2026. It replaced 2011-12 [2].
• SNA 2025 has five institutional sectors: non-financial corporations, financial corporations, general government, NPISH and households [5].

Mains Points

• Why the State steps into markets (GS-III):
• Missing markets, markets that do not reach equilibrium, and social goals together justify fiscal and monetary action.
• The Great Depression showed that full employment cannot be assumed.

• This is the basis for counter-cyclical policy, i.e. more spending or cheaper credit in a slump, less in a boom.

• The textbook model fits India only partly:

• Much of India's output comes from peasant, family and unincorporated enterprises. They use family labour and produce partly for their own use.
• Measuring them well needs direct surveys. The 2022-23 series now uses ASUSE and PLFS for household-sector GVA [3].

• This matters for GDP accuracy, for policies on the informal sector, and for how credible Indian data looks abroad.

• Flow of production vs natural endowment:

• Resource-rich poor countries show that productivity, institutions and capital formation drive wealth.

• This supports a policy focus on manufacturing, skills and infrastructure over depending on extracting natural resources.

• Statistical credibility:

• Revising the base year regularly (the aim is every 5 years) keeps weights and data sources up to date [2].
• Aligning with international standards (SNA) makes India's figures comparable with other countries' figures.
• Both strengthen evidence-based policy and investor confidence.