Aggregate Demand and Supply Notes

  • Overview of Homework and Course Expectations

    • Homework assignments are issued, with a due date set for Sunday.
    • Some textbook questions have available answers; however, they are not shared publicly.
    • Students can reach out via email or during office hours for assistance.

  • Topic of the Day: Aggregate Demand and Supply

    • Aggregate Demand (AD): This refers to the total demand for goods and services within an economy at a given overall price level and in a given time period.
    • Contrast with Micro Demand: Aggregate demand aggregates the demands of all individuals in the economy.
    • Important relationship: Aggregate Demand often associated with GDP (Gross Domestic Product).

  • Graphing Aggregate Demand

    • Axes labeled with Price Level and Quantity of Goods.
    • The demand curve slopes downwards due to three factors:
    • Wealth Effect:
      • As prices increase, purchasing power decreases, leading to a decline in real GDP.
      • Example: If the price of goods increases (like root beer), less can be purchased.
    • Interest Rate Effect:
      • Higher price levels can lead to higher interest rates as savings decrease.
      • As interest rates increase, investment decreases, contributing to a decrease in AD.
    • International Trade Effect:
      • Rising U.S. prices make foreign goods cheaper, leading to increased imports and decreased exports, thus reducing net exports (NX) and affecting AD.

  • Factors Affecting Aggregate Demand

    • Consumption (C): Influenced by expectations of future income and real wealth.
    • Investment (I): Reliant on business confidence and consumer confidence.
    • Government Spending (G): Generally a positive boost to AD.
    • Net Exports (NX): Affected by the strength of the U.S. dollar and foreign income levels, impacting how much foreign goods are bought and sold.

  • Understanding Aggregate Supply (AS)

    • Distinguish between input prices (wages, interest rates) and output prices (prices of goods produced).
    • Sticky Prices: Input prices tend to be rigid due to contracts and negotiations. Output prices can adjust more readily.
    • Short Run vs Long Run:
    • In the short run, some prices are sticky, and output can change based on fluctuations in demand.
    • In the long run, all prices can adjust, leading to a reevaluation of economic equilibrium.

  • Short Run Aggregate Supply (SRAS) Model

    • SRAS can be upward-sloping due to sticky input prices.
    • Equilibrium: The economy operates at a certain output (Y*) that represents full-employment output.

  • Shift Factors for Aggregate Supply

    • Factors affecting long-run aggregate supply could include changes in resources, technology, and institutions.
    • Shocks (like natural disasters) can cause short run shifts in aggregate supply without affecting long run potential.

  • Market Equilibrium Adjustments

    • Determine impacts on AD and AS through scenario analysis (such as changes in consumption due to increased wealth).
    • Example: Increased consumption shifts AD right, initiating a series of adjustments both short-term (temporary price increases, higher output) and long-term (renegotiated contracts leading to price adjustments).

  • Practical Application & Practice Problems

    • Emphasize the role of aggregate demand and supply in economic models.
    • Practice problems available to solidify understanding of the concepts discussed.

  • Conclusion

    • Understand the interconnectedness of AD and AS in evaluating economic performance.
    • Have questions prepared for office hours to clarify complex points.