Aggregate demand

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  • Remove bullet in graph – graph needs no additional title???
  • The order of discussion in Mankiw has been changed. The “misperceptions theory” must be moved to the bottom of the list. (This may affect the entire order of presentation following this slide.)
  • Move this slide so that it follows the next two slides. That puts the discussion in the new order of the text.
  • For consistency, title this slide, “Why the Aggregate supply curves slopes upward in the short run” like the previous two slides. Then move “The sticky-price theory” in large print to the top bullet (like the previous two slides).
  • Should title be, “Why the short-run aggregate supply…”
  • Bullet three, move the misperceptions theory to the end.
  • Aggregate demand

    1. 1. 12SHORT-RUN ECONOMIC FLUCTUATIONS
    2. 2. Aggregate Demand and Aggregate 33 SupplyCopyright © 2004 South-Western
    3. 3. Short-Run Economic Fluctuations• Economic activity fluctuates from year to year. • In most years production of goods and services rises. • On average over the past 50 years, production in the U.S. economy has grown by about 3 percent per year. • In some years normal growth does not occur, causing a recession. Copyright © 2004 South-Western
    4. 4. Short-Run Economic Fluctuations• A recession is a period of declining real incomes, and rising unemployment.• A depression is a severe recession. Copyright © 2004 South-Western
    5. 5. THREE KEY FACTS ABOUT ECONOMIC FLUCTUATIONS• Economic fluctuations are irregular and unpredictable. • Fluctuations in the economy are often called the business cycle.• Most macroeconomic variables fluctuate together.• As output falls, unemployment rises. Copyright © 2004 South-Western
    6. 6. THREE KEY FACTS ABOUT ECONOMIC FLUCTUATIONS• Most macroeconomic variables fluctuate together. • Most macroeconomic variables that measure some type of income or production fluctuate closely together. • Although many macroeconomic variables fluctuate together, they fluctuate by different amounts. Copyright © 2004 South-Western
    7. 7. THREE KEY FACTS ABOUT ECONOMIC FLUCTUATIONS• As output falls, unemployment rises. • Changes in real GDP are inversely related to changes in the unemployment rate. • During times of recession, unemployment rises substantially. Copyright © 2004 South-Western
    8. 8. Figure 1 A Look At Short-Run EconomicFluctuations (c) Unemployment Rate Percent ofLabor Force 12 10 8 Unemployment rate 6 4 2 0 1965 1970 1975 1980 1985 1990 1995 2000 Copyright © 2004 South-Western
    9. 9. EXPLAINING SHORT-RUN ECONOMIC FLUCTUATIONS• How the Short Run Differs from the Long Run • Most economists believe that classical theory describes the world in the long run but not in the short run. • Changes in the money supply affect nominal variables but not real variables in the long run. • The assumption of monetary neutrality is not appropriate when studying year-to-year changes in the economy. Copyright © 2004 South-Western
    10. 10. The Basic Model of Economic Fluctuations• Two variables are used to develop a model to analyze the short-run fluctuations. • The economy’s output of goods and services measured by real GDP. • The overall price level measured by the CPI or the GDP deflator. Copyright © 2004 South-Western
    11. 11. The Basic Model of Economic Fluctuations• The Basic Model of Aggregate Demand and Aggregate Supply • Economist use the model of aggregate demand and aggregate supply to explain short-run fluctuations in economic activity around its long-run trend. Copyright © 2004 South-Western
    12. 12. The Basic Model of Economic Fluctuations• The Basic Model of Aggregate Demand and Aggregate Supply • The aggregate-demand curve shows the quantity of goods and services that households, firms, and the government want to buy at each price level. Copyright © 2004 South-Western
    13. 13. The Basic Model of Economic Fluctuations• The Basic Model of Aggregate Demand and Aggregate Supply • The aggregate-supply curve shows the quantity of goods and services that firms choose to produce and sell at each price level. Copyright © 2004 South-Western
    14. 14. Figure 2 Aggregate Demand and Aggregate Supply... Price Level Aggregate supplyEquilibrium price level Aggregate demand 0 Equilibrium Quantity of output Output Copyright © 2004 South-Western
    15. 15. THE AGGREGATE-DEMAND CURVE• The four components of GDP (Y) contribute to the aggregate demand for goods and services. Y = C + I + G + NX Copyright © 2004 South-Western
    16. 16. Figure 3 The Aggregate-Demand Curve... Price Level P P21. A decrease Aggregatein the price demandlevel . . . 0 Y Y2 Quantity of Output 2. . . . increases the quantity of goods and services demanded. Copyright © 2004 South-Western
    17. 17. Why the Aggregate-Demand Curve IsDownward Sloping• The Price Level and Consumption: The Wealth Effect• The Price Level and Investment: The Interest Rate Effect• The Price Level and Net Exports: The Exchange-Rate Effect Copyright © 2004 South-Western
    18. 18. Why the Aggregate-Demand Curve IsDownward Sloping• The Price Level and Consumption: The Wealth Effect • A decrease in the price level makes consumers feel more wealthy, which in turn encourages them to spend more. • This increase in consumer spending means larger quantities of goods and services demanded. Copyright © 2004 South-Western
    19. 19. Why the Aggregate-Demand Curve IsDownward Sloping• The Price Level and Investment: The Interest Rate Effect • A lower price level reduces the interest rate, which encourages greater spending on investment goods. • This increase in investment spending means a larger quantity of goods and services demanded. Copyright © 2004 South-Western
    20. 20. Why the Aggregate-Demand Curve IsDownward Sloping• The Price Level and Net Exports: The Exchange-Rate Effect • When a fall in the price level causes interest rates to fall, the real exchange rate depreciates, which stimulates net exports. • The increase in net export spending means a larger quantity of goods and services demanded. Copyright © 2004 South-Western
    21. 21. Why the Aggregate-Demand Curve MightShift• The downward slope of the aggregate demand curve shows that a fall in the price level raises the overall quantity of goods and services demanded.• Many other factors, however, affect the quantity of goods and services demanded at any given price level.• When one of these other factors changes, the aggregate demand curve shifts. Copyright © 2004 South-Western
    22. 22. Why the Aggregate-Demand Curve MightShift• Shifts arising from • Consumption • Investment • Government Purchases • Net Exports Copyright © 2004 South-Western
    23. 23. Shifts in the Aggregate Demand CurvePriceLevel P1 D2 Aggregate demand, D1 0 Y1 Y2 Quantity of Output Copyright © 2004 South-Western
    24. 24. THE AGGREGATE-SUPPLY CURVE• In the long run, the aggregate-supply curve is vertical.• In the short run, the aggregate-supply curve is upward sloping. Copyright © 2004 South-Western
    25. 25. THE AGGREGATE-SUPPLY CURVE• The Long-Run Aggregate-Supply Curve • In the long run, an economy’s production of goods and services depends on its supplies of labor, capital, and natural resources and on the available technology used to turn these factors of production into goods and services. • The price level does not affect these variables in the long run. Copyright © 2004 South-Western
    26. 26. Figure 4 The Long-Run Aggregate-Supply Curve Price Level Long-run aggregate supply P P2 2. . . . does not affect1. A change the quantity of goodsin the price and services suppliedlevel . . . in the long run. 0 Natural rate Quantity of of output Output Copyright © 2004 South-Western
    27. 27. THE AGGREGATE-SUPPLY CURVE• The Long-Run Aggregate-Supply Curve • The long-run aggregate-supply curve is vertical at the natural rate of output. • This level of production is also referred to as potential output or full-employment output. Copyright © 2004 South-Western
    28. 28. Why the Long-Run Aggregate-Supply CurveMight Shift• Any change in the economy that alters the natural rate of output shifts the long-run aggregate-supply curve.• The shifts may be categorized according to the various factors in the classical model that affect output. Copyright © 2004 South-Western
    29. 29. Why the Long-Run Aggregate-Supply CurveMight Shift• Shifts arising • Labor • Capital • Natural Resources • Technological Knowledge Copyright © 2004 South-Western
    30. 30. Figure 5 Long-Run Growth and Inflation 2. . . . and growth in the Long-run money supply shifts aggregate aggregate demand . . . supply, LRAS1980 LRAS1990 LRAS 2000 Price Level 1. In the long run, technological progress shifts P2000 long-run aggregate supply . . . 4. . . . and ongoing inflation. P1990 Aggregate Demand, AD2000 P1980 AD1990 AD1980 0 Y1980 Y1990 Y2000 Quantity of Output 3. . . . leading to growth in output . . . Copyright © 2004 South-Western
    31. 31. A New Way to Depict Long-Run Growth andInflation• Short-run fluctuations in output and price level should be viewed as deviations from the continuing long-run trends. Copyright © 2004 South-Western
    32. 32. Why the Aggregate-Supply Curve SlopesUpward in the Short Run• In the short run, an increase in the overall level of prices in the economy tends to raise the quantity of goods and services supplied.• A decrease in the level of prices tends to reduce the quantity of goods and services supplied. Copyright © 2004 South-Western
    33. 33. Figure 6 The Short-Run Aggregate-Supply Curve Price Level Short-run aggregate supply P P21. A decrease 2. . . . reduces the quantityin the price of goods and serviceslevel . . . supplied in the short run. 0 Y2 Y Quantity of Output Copyright © 2004 South-Western
    34. 34. Why the Aggregate-Supply Curve SlopesUpward in the Short Run• The Misperceptions Theory• The Sticky-Wage Theory• The Sticky-Price Theory Copyright © 2004 South-Western
    35. 35. Why the Aggregate-Supply Curve SlopesUpward in the Short Run• The Misperceptions Theory • Changes in the overall price level temporarily mislead suppliers about what is happening in the markets in which they sell their output: • A lower price level causes misperceptions about relative prices. • These misperceptions induce suppliers to decrease the quantity of goods and services supplied. Copyright © 2004 South-Western
    36. 36. Why the Aggregate-Supply Curve SlopesUpward in the Short Run• The Sticky-Wage Theory • Nominal wages are slow to adjust, or are “sticky” in the short run: • Wages do not adjust immediately to a fall in the price level. • A lower price level makes employment and production less profitable. • This induces firms to reduce the quantity of goods and services supplied. Copyright © 2004 South-Western
    37. 37. The Sticky-Price Theory • Prices of some goods and services adjust sluggishly in response to changing economic conditions: • An unexpected fall in the price level leaves some firms with higher-than-desired prices. • This depresses sales, which induces firms to reduce the quantity of goods and services they produce. Copyright © 2004 South-Western
    38. 38. Why the Short-Run Aggregate-Supply CurveMight Shift• Shifts arising • Labor • Capital • Natural Resources. • Technology. • Expected Price Level. Copyright © 2004 South-Western
    39. 39. Why the Aggregate Supply Curve Might Shift• An increase in the expected price level reduces the quantity of goods and services supplied and shifts the short-run aggregate supply curve to the left.• A decrease in the expected price level raises the quantity of goods and services supplied and shifts the short-run aggregate supply curve to the right. Copyright © 2004 South-Western
    40. 40. Figure 7 The Long-Run Equilibrium Price Level Long-run aggregate Short-run supply aggregate supplyEquilibrium A price Aggregate demand 0 Natural rate Quantity of of output Output Copyright © 2004 South-Western
    41. 41. Figure 8 A Contraction in Aggregate Demand 2. . . . causes output to fall in the short run . . . Price Level Long-run Short-run aggregate aggregate supply, AS supply AS2 3. . . . but over time, the short-run P A aggregate-supply curve shifts . . . P2 B 1. A decrease in aggregate demand . . . P3 C Aggregate demand, AD AD2 0 Y2 Y Quantity of 4. . . . and output returns Output to its natural rate. Copyright © 2004 South-Western
    42. 42. TWO CAUSES OF ECONOMIC FLUCTUATIONS• Shifts in Aggregate Demand • In the short run, shifts in aggregate demand cause fluctuations in the economy’s output of goods and services. • In the long run, shifts in aggregate demand affect the overall price level but do not affect output. Copyright © 2004 South-Western
    43. 43. TWO CAUSES OF ECONOMIC FLUCTUATIONS• An Adverse Shift in Aggregate Supply • A decrease in one of the determinants of aggregate supply shifts the curve to the left: • Output falls below the natural rate of employment. • Unemployment rises. • The price level rises. Copyright © 2004 South-Western
    44. 44. Figure 10 An Adverse Shift in Aggregate Supply 1. An adverse shift in the short- run aggregate-supply curve . . . Price Level Long-run Short-run aggregate AS2 aggregate supply supply, AS B P2 A P3. . . . andthe pricelevel to rise. Aggregate demand 0 Y2 Y Quantity of 2. . . . causes output to fall . . . Output Copyright © 2004 South-Western
    45. 45. The Effects of a Shift in Aggregate Supply• Stagflation • Adverse shifts in aggregate supply cause stagflation —a period of recession and inflation. • Output falls and prices rise. • Policymakers who can influence aggregate demand cannot offset both of these adverse effects simultaneously. Copyright © 2004 South-Western
    46. 46. The Effects of a Shift in Aggregate Supply• Policy Responses to Recession • Policymakers may respond to a recession in one of the following ways: • Do nothing and wait for prices and wages to adjust. • Take action to increase aggregate demand by using monetary and fiscal policy. Copyright © 2004 South-Western
    47. 47. Figure 11 Accommodating an Adverse Shift in Aggregate Supply 1. When short-run aggregate supply falls . . . Price Level Long-run Short-run aggregate AS2 aggregate supply supply, AS P3 C 2. . . . policymakers can P2 accommodate the shift A by expanding aggregate3. . . . which P demand . . .causes theprice levelto rise 4. . . . but keeps output AD2further . . . at its natural rate. Aggregate demand, AD 0 Natural rate Quantity of of output Output Copyright © 2004 South-Western
    48. 48. Summary• All societies experience short-run economic fluctuations around long-run trends.• These fluctuations are irregular and largely unpredictable.• When recessions occur, real GDP and other measures of income, spending, and production fall, and unemployment rises. Copyright © 2004 South-Western
    49. 49. Summary• Economists analyze short-run economic fluctuations using the aggregate demand and aggregate supply model.• According to the model of aggregate demand and aggregate supply, the output of goods and services and the overall level of prices adjust to balance aggregate demand and aggregate supply. Copyright © 2004 South-Western
    50. 50. Summary• The aggregate-demand curve slopes downward for three reasons: a wealth effect, an interest rate effect, and an exchange rate effect.• Any event or policy that changes consumption, investment, government purchases, or net exports at a given price level will shift the aggregate-demand curve. Copyright © 2004 South-Western
    51. 51. Summary• In the long run, the aggregate supply curve is vertical.• The short-run, the aggregate supply curve is upward sloping.• The are three theories explaining the upward slope of short-run aggregate supply: the misperceptions theory, the sticky-wage theory, and the sticky-price theory. Copyright © 2004 South-Western
    52. 52. Summary• Events that alter the economy’s ability to produce output will shift the short-run aggregate-supply curve.• Also, the position of the short-run aggregate- supply curve depends on the expected price level.• One possible cause of economic fluctuations is a shift in aggregate demand. Copyright © 2004 South-Western
    53. 53. Summary• A second possible cause of economic fluctuations is a shift in aggregate supply.• Stagflation is a period of falling output and rising prices. Copyright © 2004 South-Western

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