Chapter 24: The Aggregate Supply and Aggregate Demand Model

Chapter 24: The Aggregate Supply and Aggregate Demand Model

Overview of the Model

• Understanding the Aggregate Supply (AS) and Aggregate Demand (AD) model is essential for analyzing macroeconomic conditions.

• It illustrates the total supply and demand within an economy at various price levels.

Key Historical Context

• Housing Bubble (Peak Era):

  • Many secured loans for new houses before the decline beginning in 2006.

  • Sales of new single-family homes peaked around 2005, then dropped through 2011, with slow recovery noted by 2014.

  • New home sales represent around 10% of the US housing market.

Macroeconomic Perspectives

• Classical vs. Keynesian Economics:

  • Classical: Economy adjusts automatically (Laissez-faire).

  • Keynesian: Cyclical unemployment can occur, requiring government management of instability.

• Say's Law: asserts that supply creates its own demand.

Aggregate Demand (AD) Fundamentals

• Components of Aggregate Demand:

  • AD = C + I + G + NX

  • C: Consumer Spending

  • I: Investment Spending

  • G: Government Spending

  • NX: Net Exports

• Determinants of AD:

  • Factors affecting consumer spending, investment, government purchases, and net exports:

  • Consumer Wealth

  • Household Borrowing

  • Consumer Expectations

  • Personal Taxes

Investment Spending Dynamics

• Influenced by:

  • Real interest rates

  • Expected returns and business conditions

  • Costs associated with technology, excess capacity, and business taxes

• Example Calculation:

  • If Jane invests $1000 with an expected return of $45 ($45/$1000 = 4.5%) and the real interest rate is 3%, she will choose to invest because expected return > real interest rate.

Government Spending Effects

• Government Spending Increases:

  • Typically leads to increased AD (assuming no change in interest/tax rates).

• Government Spending Decreases:

  • Results in decreased AD (e.g., reduced military spending).

Net Export Spending Factors

• Influences include:

  • National income abroad

  • Exchange rates (depreciation/appreciation of the dollar)

  • Trade policies

Aggregate Supply (AS) Concept

• Definitions of AS:

  • Total real output produced at each price level based on time horizon:

  • Immediate Short Run: Both prices fixed

  • Short Run: Input prices fixed, output prices variable

  • Long Run: Both input and output prices variable

• Factors Affecting AS include:

  • Resource prices

  • Technology advancements

  • Overall productivity

Aggregate Equilibrium

• Intersection of aggregate demand and supply determines the overall output and price level in the economy.

• Illustrates how shifts in AD or AS can lead to changes in real output and pricing strategies.

Applications of AS-AD Model

• 2007 Financial Crisis Impact:

  • Decline in aggregate expenditures and significant drops in consumption and investment spending.

• 1970s Oil Crisis Analysis:

  • OPEC's oil supply cut led to soaring oil prices and subsequent decline in aggregate supply.

Discussion Topics

• Recent economic events (post-2020), including:

  • Impact of the pandemic

  • Global economic shutdowns

  • Stimulus policies leading to inflation and volatility

  • Current high interest rates and potential recession fears.

Review Questions

• Practice identifying the causes and effects of demand and supply shifts on the economy.

• Engage with scenarios to apply theoretical knowledge of AD and AS in modern economic conditions.

• Example questions include evaluating recession triggers and expectations regarding unemployment and inflation.

End of Notes