Introduction to Macro Economics Exercise Solutions | KalviGavani

Macro economics is the branch of economics that studies the behaviour and performance of the economy as a whole. It deals with aggregate variables such as national income, total employment, general price level, and overall output. The term was coined by Ragnar Frisch in 1933.

| Basis | Micro Economics | Macro Economics | |---|---|---| | Unit of study | Individual units (firm, consumer) | Economy-wide aggregates | | Also called | Price theory | Income and employment theory | | Key variables | Individual price, demand, supply | National income, inflation, employment | | Approach | Bottom-up | Top-down | | Pioneers | Alfred Marshall | J.M. Keynes |

A stock variable is one that is measured at a specific point in time. It has no time dimension. Examples: (i) Wealth — measured as on a particular date; (ii) Capital — the stock of productive assets at a given time.

A flow variable is one that is measured over a period of time (a day, month, or year). Examples: (i) National income — income earned during a year; (ii) Investment — capital formation during a period.

The scope of macro economics includes: (i) National income analysis — measuring GDP, GNP, NNP; (ii) Employment and unemployment — determinants and policies; (iii) General price level — inflation and deflation; (iv) Business cycles — boom, recession, and recovery; (v) International trade and balance of payments; (vi) Economic growth and development.

Static economics studies economic phenomena at a point in time under the assumption of ceteris paribus (other things remaining the same). It does not consider the time element or the process of change. Dynamic economics, on the other hand, studies the process of change over time and analyses how the economy moves from one equilibrium to another. Static analysis gives a snapshot; dynamic analysis gives a movie.

Partial equilibrium, developed by Alfred Marshall, analyses a single market in isolation, assuming that conditions in all other markets remain unchanged. It is useful for studying the price determination of a single commodity, but it ignores the interdependence among markets.

Micro Economics: - Studies individual economic units — a consumer, a firm, or a particular market. - Focuses on price determination of individual commodities and factors of production. - Also known as price theory. - Uses partial equilibrium analysis (Marshallian approach). - Deals with micro variables like individual demand, individual supply, and relative prices. - Founded by Alfred Marshall (Principles of Economics, 1890). - Assumes other things remain equal (ceteris paribus). Macro Economics: - Studies the economy as an aggregate whole. - Focuses on national income, total employment, and the general price level. - Also known as income and employment theory. - Uses general equilibrium analysis (Walrasian approach) and aggregate analysis. - Deals with macro variables like aggregate demand, aggregate supply, and the price level. - Founded by J.M. Keynes (The General Theory, 1936). - Considers the interdependence of all sectors of the economy. Key distinction: Micro economics is a bottom-up approach (from individual units to the market), while macro economics is a top-down approach (from the whole economy to individual parts). Both are complementary — neither can be studied in complete isolation.

Scope of Macro Economics: 1. National Income Analysis: Macro economics studies the size and composition of national income (GDP, GNP, NNP), its distribution, and the factors that determine it. 2. Employment and Unemployment: It analyses the level of employment, causes of unemployment, and policies to achieve full employment. Keynes's theory of effective demand is central here. 3. General Price Level / Inflation: It examines inflation (rising prices), deflation (falling prices), and stagflation, and their impact on the economy. 4. Business Cycles: Macro economics studies the fluctuations in economic activity — boom, recession, depression, and recovery — and suggests counter-cyclical measures. 5. Economic Growth and Development: It analyses the long-run determinants of growth — capital accumulation, technological progress, and population growth. 6. International Trade and Balance of Payments: It deals with exchange rates, trade policies, and the balance of payments position of a country. Importance of Macro Economics: 1. Policy formulation: Helps governments design fiscal policy (taxation, public expenditure) and monetary policy (interest rates, money supply). 2. Understanding economic problems: Provides a framework to diagnose issues like poverty, unemployment, and inflation. 3. Economic planning: Essential for formulating five-year plans and development strategies. 4. International comparison: Enables comparison of economic performance across countries using standardised aggregates. 5. Business decisions: Firms use macro indicators (GDP growth, interest rates) for strategic planning.

| Basis | Stock | Flow | |---|---|---| | Definition | Measured at a point in time | Measured over a period of time | | Time dimension | No time dimension | Has a time dimension (per day, per year) | | Examples | Wealth, capital, money supply, foreign exchange reserves, population | Income, expenditure, investment, production, exports | | Relationship | Stock is the result of accumulated flows | Flow changes the stock over time | | Measurement | As on a date (e.g., wealth as on 31 March 2026) | During a period (e.g., income for the year 2025-26) | Key relationships: - Capital (stock) increases through investment (flow) and decreases through depreciation (flow). - Wealth (stock) increases through saving (flow). - Money supply (stock) changes due to the flow of new currency issued by the central bank. Important point: Some variables can be both stock and flow depending on context. For example, "deposits in a bank" is a stock when measured at a point, but "new deposits made" is a flow over a period.

J.M. Keynes's Contributions: 1. The General Theory of Employment, Interest and Money (1936): This groundbreaking book challenged the classical view that markets always self-adjust to full employment. Keynes argued that equilibrium could exist at less than full employment. 2. Theory of Effective Demand: Keynes demonstrated that the level of employment and output is determined by effective demand — the point where aggregate demand equals aggregate supply. When effective demand is insufficient, unemployment results. 3. Refutation of Say's Law: Classical economists believed that "supply creates its own demand." Keynes showed that demand could fall short of supply, leading to overproduction and unemployment. 4. Liquidity Preference Theory: Keynes developed a new theory of interest based on liquidity preference — the demand for money as an asset. Interest is the reward for parting with liquidity. 5. Multiplier Concept: Keynes introduced the investment multiplier (k = 1/(1-MPC)), showing how an initial increase in investment leads to a magnified increase in national income. 6. Policy Implications: Keynes advocated active government intervention through fiscal policy (public works, deficit spending) to lift the economy out of depression — a radical departure from the classical laissez-faire approach. 7. Short-run Focus: Unlike the classicals who focused on the long run, Keynes emphasised the short run, famously stating, "In the long run we are all dead."