Lecture 3: Macroeconomic Models and Indicators

Introduction to Advanced Macroeconomic Models

• Macroeconomics focuses on the behavior of aggregate variables: GDP, inflation, and employment
• IS-LM and AD-AS are key frameworks to analyze macroeconomic equilibrium
• These models link real and monetary sectors of the economy
• Understanding these models aids in crafting monetary and fiscal policies

Key terms: Macroeconomics, Policy Formulation

Gross Domestic Product (GDP): Foundation of Macroeconomics

• GDP measures a nation's total economic output within a specific timeframe
• It is calculated using three methods: production, income, and expenditure approaches
• Nominal GDP and Real GDP are key concepts to assess growth
• GDP per capita measures economic output per person, indicating living standards
• Limitations include its inability to capture inequality or environmental quality

Key terms: Gross Domestic Product (GDP), Nominal GDP, Real GDP

Inflation: Definition and Measurements

• Inflation represents the rate of increase in overall price levels in an economy
• Consumer Price Index (CPI) and Producer Price Index (PPI) are two common measures
• Hyperinflation and deflation reflect extremes of inflationary trends
• Inflation affects purchasing power, savings, and interest rates
• Economists distinguish between demand-pull and cost-push inflation

Key terms: Inflation, Demand-Pull Inflation, Cost-Push Inflation

Unemployment: Types and Metrics

• Unemployment represents the share of the labour force that is willing and able to work but cannot find a job
• Key types include frictional, structural, cyclical, and seasonal
• Natural rate of unemployment includes structural and frictional unemployment even in healthy economies
• The unemployment rate is calculated as (Unemployed ÷ Labour Force) × 100
• High unemployment has social, economic, and political consequences

Key terms: Unemployment Rate, Frictional Unemployment, Structural Unemployment

The IS-LM Model: Introduction and Foundations

• The IS-LM model, introduced by John Hicks (1937) and later expanded by Alvin Hansen, maps the equilibrium in goods and money markets.
• IS (Investment-Savings) curve represents equilibrium in the goods market.
• LM (Liquidity preference-Money supply) curve represents equilibrium in the money market.
• Assumptions of the IS-LM model: fixed price levels, closed economy, and Keynesian principles of aggregate demand.

Key terms: IS-LM Model, John Hicks, Keynesian Economics

Shifts in IS and LM Curves: Policy Impacts

• Fiscal policies shift the IS curve (e.g., changes in government spending or taxation).
• Monetary policies shift the LM curve (e.g., changes to money supply or interest rates).
• An increase in government spending shifts the IS curve right, boosting output and interest rates.
• Expanding the money supply shifts the LM curve right, lowering interest rates and increasing output.
• Key applications include addressing recessions and inflationary periods.

Key terms: Fiscal Policy, Monetary Policy

The IS-LM Model: Equilibrium and Dynamics

• Equilibrium occurs at the intersection of the IS and LM curves
• The IS curve represents combinations of interest rates and output where the goods market is in equilibrium (Keynesian foundation)
• The LM curve represents combinations of interest rates and output where the money market is in equilibrium (Liquidity Preference framework by Keynes, 1936)
• Movement along the curves vs. shifts in the curves indicates differing economic phenomena
• Effectiveness of fiscal and monetary policies depends on the slope of the curves

Key terms: IS Curve, LM Curve, Liquidity Preference

Shifts in Aggregate Demand and Supply (AD-AS) Framework

• AD-AS framework builds on classical and Keynesian theories to analyze output, prices, and employment
• Aggregate demand (AD) curve is downward sloping: lower price levels increase real wealth, exports, and investment
• Aggregate supply (AS) comes in two forms: short-run AS (SRAS) and long-run AS (LRAS)
• Shifts in AD arise from changes in consumer confidence, fiscal policy, or monetary policy
• Shifts in AS are caused by factors like technology advancements, input cost changes, or labor productivity

Key terms: Aggregate Demand, Short-Run Aggregate Supply (SRAS), Long-Run Aggregate Supply (LRAS)

The IS-LM Model and Fiscal Policy

• The IS curve captures equilibrium in the goods market (Investment-Savings balance), while the LM curve represents equilibrium in the money market (Liquidity preference-Money supply balance).
• Fiscal policy changes—such as government spending (G) and taxation (T)—shift the IS curve.
• Increased government spending (G↑) shifts the IS curve to the right, increasing output and interest rates.
• Decreased taxation (T↓) similarly shifts the IS curve to the right, stimulating aggregate demand.
• However, the changes in interest rates affect investment, limiting the overall effectiveness of fiscal policy (crowding-out effect).

Key terms: IS Curve, Crowding-Out Effect

Monetary Policy in the IS-LM Model

• The LM curve shifts due to changes in monetary policy, such as changes in the money supply (M).
• Increased money supply (M↑) shifts the LM curve to the right, lowering interest rates and increasing output.
• Decreased money supply (M↓) shifts the LM curve to the left, increasing interest rates and reducing output.
• The slope of the LM curve is influenced by the interest-elasticity of money demand and the responsiveness of money supply.
• The effectiveness of monetary policy depends on the steepness of the IS curve (investment sensitivity to interest rates).

Key terms: LM Curve, Quantitative Easing

Conclusion: Connections Across Models

• The IS-LM framework and AD-AS model provide complementary lenses for understanding macroeconomic dynamics.
• While the IS-LM model emphasizes short-term equilibrium through interaction of goods and money markets, the AD-AS framework encompasses both short- and long-term supply-side constraints.
• Economic indicators like GDP, inflation, and unemployment are critical metrics in policy application.
• Real-world application requires blending theoretical insights with empirical observations.
• Both models demonstrate how policy decisions can carry unintended consequences (e.g., crowding-out, inflationary pressures).

Key terms: Policy Mix, Potential GDP

References

• Mankiw, N.G. (2021) Principles of Economics. 9th edn. Boston: Cengage Learning.
• Samuelson, P.A. and Nordhaus, W.D. (2020) Economics. 20th edn. New York: McGraw-Hill.
• Kuznets, S. (1934) 'National Income, 1929-1932', National Bureau of Economic Research.
• OECD (2021) Measuring the Economy: A Guide. Paris: OECD Publishing.
• Friedman, M. (1963) Inflation: Causes and Consequences. Princeton: Princeton University Press.
• Phillips, A.W. (1958) 'The Relation Between Unemployment and the Rate of Change of Money Wage Rates in the UK', Economica, 25(100), pp. 283-299.
• Keynes, J.M. (1936) The General Theory of Employment, Interest, and Money. London: Macmillan.
• Blanchard, O.J. and Fischer, S. (1989) Lectures on Macroeconomics. Cambridge, MA: MIT Press.
• Hicks, J.R. (1937) 'Mr. Keynes and the Classics', Econometrica, 5(2), pp. 147-159.
• Blanchard, O. (2021) Macroeconomics. 8th edn. Harlow: Pearson.
• Keynes, J.M. (1936) The General Theory of Employment, Interest and Money. London: Palgrave Macmillan.
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• Blanchard, O. (2018) Macroeconomics. 7th edn. Harlow: Pearson Education.
• Hicks, J.R. (1937) 'Mr. Keynes and the 'Classics'; A Suggested Interpretation', Econometrica, 5(2), pp. 147–159.
• Bennett T. McCallum (1983) 'Monetary Policy in the IS-LM Model', Carnegie-Rochester Conference Series on Public Policy.
• Blanchard, O. (2017) Macroeconomics. 7th edn. Harlow: Pearson Education.
• Mankiw, N.G. (2021) Principles of Macroeconomics. 9th edn. Boston: Cengage Learning.