Detailed Economic Fluctuations and the AD-AS Model Notes

Economic Concepts and Principles

Economic Fluctuations Overview

  • Economic Activity

    • Fluctuates from year to year.

    • Recession: Economic contraction characterized by declining real incomes and rising unemployment.

    • Depression: A severe recession with extreme declines in economic activity.

Key Facts About Economic Fluctuations

  1. Irregularity and Unpredictability: Economic fluctuations are irregular and unpredictable.

  2. Interconnectedness of Macroeconomic Quantities: Most macroeconomic quantities fluctuate together, making recessions affect the entire economy.

  3. Unemployment Correlation: As output falls during recessions, unemployment tends to rise.

Classical Dichotomy and Short-Run Fluctuations

  • Classical Dichotomy

    • Separation of real variables (such as output and employment) from nominal variables (such as the money supply).

  • Monetary Neutrality

    • In the long run, changes in the money supply affect only nominal variables and not real variables (i.e., GDP, unemployment).

  • Short-Run Insights

    • In the short run, monetary neutrality does not hold, and real and nominal variables can be affected by changes in the money supply.

Aggregate Demand and Aggregate Supply Model (AD-AS Model)

  • Purpose: This model is used by economists to analyze economic fluctuations.

  • Aggregate-Demand Curve: Illustrates the quantity of goods and services households, firms, the government, and customers abroad want to buy at each price level. It slopes downward due to three effects:

    1. Wealth Effect: A decrease in the price level raises the real value of money, stimulating consumer spending.

    2. Interest-Rate Effect: Lower price levels decrease interest rates, stimulating investment spending.

    3. Exchange-Rate Effect: A lower price level causes the currency to depreciate, increasing net exports.

  • Aggregate-Supply Curve: Depicts the quantity of goods and services that firms are willing to produce and sell at each price level, typically upward sloping. The long-run aggregate supply curve (LRAS) is vertical, suggesting that in the long run, price levels don’t affect the economy's output.

Shifts in the Aggregate-Demand Curve

  • Shifts can arise from changes in:

    • Consumption (C): Influenced by tax changes, consumer confidence, etc.

    • Investment (I): Driven by technology improvements, interest rates, etc.

    • Government Purchases (G): Policy changes affecting government spending.

    • Net Exports (NX): Changes in foreign demand or exchange rates.

Shifts in the Aggregate-Supply Curve

  • Long-run AS curve can shift due to changing factors:

    • Labor: Increase leads to a right shift; decrease shifts left.

    • Capital: More capital available shifts right; depletion shifts left.

    • Natural Resources and Technology: Discovery or enhancement shifts right, while depletion or technological regress shifts left.

Causes of Economic Fluctuations

  • Aggregate Demand Shifts: E.g., pessimism can decrease AD, lowering output and prices.

  • Aggregate Supply Shifts: Increasing production costs can shift AS to the left.

Historical Economic Events

  • The Great Depression (1930s): Significant decline in AD led to severe drops in GDP, prices, and rising unemployment.

  • World War II Boom (1940s): Increased government spending led to a substantial rise in GDP and decreased unemployment.

  • The Great Recession (2008-2009): Financial crisis led to a contraction in AD, significant GDP decline, and a spike in unemployment, prompting large-scale governmental and monetary interventions.