Economics Fluctuations

Introduction to Economic Fluctuations

Facts About the Business Cycle

  • GDP growth averages approximately 33 percent per year over the long run, but experiences considerable fluctuations in the short run.
  • Consumption and investment both fluctuate alongside GDP. However, consumption tends to be less volatile, while investment is more volatile than GDP.
  • Unemployment increases during recessions and decreases during expansions.
  • Okun’s Law: There is a negative relationship between GDP and unemployment.
  • Index of Leading Economic Indicators (LEI)
    • Published monthly by the Conference Board.
    • Aims to predict changes in economic activity six to nine months in the future.
    • Used for planning by businesses and governments, but it's not a perfect predictor.
  • Components of the LEI index:
    • Average workweek in manufacturing
    • Initial weekly claims for unemployment insurance
    • New orders for consumer goods and materials
    • New orders, nondefense capital goods
    • ISM new orders index
    • New building permits issued
    • Index of stock prices
    • Lending credit index
    • Yield spread (10 years minus 3 months) on Treasuries
    • Index of consumer expectations

Time Horizons in Macroeconomics

  • Long Run: Prices are flexible and respond to supply and demand changes.
  • Short Run: Many prices are sticky or predetermined. The economy behaves differently due to these sticky prices.

Classical Macro Theory Recap (Chapters 3–10)

  • Output is supply-side determined based on:
    • Capital supply
    • Labor supply
    • Technology
  • Changes in demand for goods and services (C, I, G) only affect prices, not quantities.
  • Assumes complete price flexibility.
  • Applies to the long run.

Sticky Prices

  • Output and employment depend on demand.
  • Demand is affected by:
    • Fiscal policy (G and T)
    • Monetary policy (M)
    • Exogenous factors, such as changes in C or I

The Model of Aggregate Demand and Supply

  • This model is used by most mainstream economists and policymakers to understand economic fluctuations and stabilization policies.
  • It illustrates how the price level and aggregate output are determined.
  • It highlights the differences in the economy’s behavior in the short run versus the long run.

Aggregate Demand

  • The aggregate demand curve illustrates the relationship between the price level and the quantity of output demanded.
  • A simple theory of aggregate demand based on the quantity theory of money is used.

The Quantity Equation as Aggregate Demand

  • Recall the quantity equation from Chapter 4: MV=PYM V = P Y
  • Given values for M and V, this equation implies an inverse relationship between P and Y.

The Downward-Sloping AD Curve

  • An increase in the price level (P) causes a decrease in real money balances (MP\frac{M}{P}), leading to a decrease in the demand for goods and services.

Shifting the AD Curve

  • A reduction in the money supply (M) shifts the aggregate demand curve to the left.
  • An increase in the money supply (M) shifts the aggregate demand curve to the right.

Aggregate Supply in the Long Run

  • In the long run, output is determined by factor supplies and technology.
  • Yˉ\bar{Y} is the full-employment or natural level of output where the economy’s resources are fully employed.
  • Full employment means that unemployment equals its natural rate (not zero).

The Long-Run Aggregate Supply Curve

  • In the long run, output is determined by the amounts of capital and labor and by the available technology; it does not depend on the price level.
  • Therefore, the long-run aggregate supply (LRAS) curve is vertical.

Long-Run Effects of a Decrease in M

  • Starting at initial equilibrium A, a decrease in M shifts AD inward.
  • The economy reaches a new equilibrium at B with a lower price level but the same level of output.

Aggregate Supply in the Short Run

  • Many prices are sticky in the short run.
  • Assume all prices are stuck at a predetermined level in the short run.
  • Firms are willing to sell as much as customers are willing to buy at that price level.
  • Therefore, the short-run aggregate supply (SRAS) curve is horizontal.

The Short-Run Aggregate Supply Curve

  • The SRAS curve is horizontal.
  • The price level is fixed at a predetermined level (Pˉ\bar{P}), and firms sell as much as buyers demand.

Short-Run Effects of a Decrease in M

  • Starting in initial equilibrium at A, M decreases.
  • The decrease in M causes AD to shift inward.
  • The inward shift causes the economy to move to a new equilibrium at B, where output falls, and the price level remains the same.

From the Short Run to the Long Run

  • Over time, prices gradually become “unstuck.”
  • The adjustment of prices is what moves the economy to its long-run equilibrium.

The Short- and Long-Run Effects of a Decrease in M

  • The inward shift in AD causes the economy to move to a new short-run equilibrium at B, and then prices adjust, and the economy reaches the new long-run equilibrium at C.

Shocks

  • Shocks are exogenous changes in aggregate supply or demand.
  • Shocks temporarily push the economy away from full employment.
  • Example: exogenous decrease in velocity.
  • If the money supply is held constant, a decrease in V means people will be using their money in fewer transactions, causing a decrease in demand for goods and services.

The Effects of a Positive Demand Shock

  • A positive demand shock shifts AD outward to AD2, and the economy has a new short-run equilibrium at B.
  • The economy self-adjusts with increased prices and causes the economy to reach the new long-run equilibrium at C.

Supply Shocks

  • A supply shock alters production costs and affects the prices that firms charge (also called price shocks).
  • Examples of adverse supply shocks:
    • Bad weather reduces crop yields, pushing up food prices.
    • Oil cartel raise the price of oil.
  • Favorable supply shocks lower costs and prices.

CASE STUDY: The 1970s Oil Shocks

  • Early 1970s: OPEC coordinated a reduction in the supply of oil.
  • Oil prices rose:
    • 1111 percent in 1973
    • 6868 percent in 1974
    • 1616 percent in 1975
  • Sharp oil price increases are supply shocks because they significantly impact production costs and prices.

Predicted Effects of the Oil Shock

  • Inflation rate up
  • Output down
  • Unemployment up
  • …and then a gradual recovery
  • Late 1970s: As the economy was recovering, oil prices shot up again, causing another huge supply shock!

The 1980s Oil Shocks

  • 1980s: A favorable supply shock—a significant fall in oil prices
  • As the model predicts, inflation and unemployment fell.

Stabilization Policy

  • Stabilization policy: policy actions aimed at reducing the severity of short-run economic fluctuations.
  • Example: using monetary policy to combat the effects of adverse supply shocks

Stabilizing Output with Monetary Policy

  • A negative supply shock shifts SRAS up.
  • Without intervention from the Central Bank, the economy would reach a new equilibrium at B.
  • However, the Central Bank responds by increasing the money supply, shifting AD out, resulting in a new equilibrium at C (with higher price level, and no reduction in output).

The Covid-19 Recession

  • Initially, the shock to the economy was an inward shift in LRAS.
  • Businesses closed.
  • Businesses that remained open saw decreased productivity because of social distancing.
  • However, as businesses closed, consumers lost the ability to spend money, AD shifted inward due to C decreasing.
  • Unable to dine-in at restaurants
  • Unable to travel
  • Unable to attend concerts, movies, sporting events, museums, etc.
  • Ending the recession is foremost a public health issue, not an economics issue.

Chapter Summary

  • Long run: Prices are flexible, output and employment are always at their natural rates, and the classical theory applies.
  • Short run: Prices are sticky, and shocks can push output and employment away from their natural rates.
  • Aggregate demand and supply: a framework to analyze economic fluctuations
  • The aggregate demand curve slopes downward.
  • The long-run aggregate supply curve is vertical because output depends on technology and factor supplies but not prices.
  • The short-run aggregate supply curve is horizontal because prices are sticky at predetermined levels.
  • Shocks to aggregate demand and supply cause fluctuations in GDP and employment in the short run.
  • The Fed can attempt to stabilize the economy with monetary policy.