1. Aggregate Demand and Aggregate Supply
Chapter 10
Aggregate Demand and Aggregate Supply
Slides created by Dr. Amy Scott
©2010  Worth Publishers 1

2. Chapter Objectives The aggregate demand curve
The aggregate supply curve
Long-run vs. Short-run aggregate supply curve
How the AS–AD model is used to analyze economic fluctuations
How monetary policy and fiscal policy can stabilize the economy

3. Aggregate Demand
The aggregate demand curve shows the relationship between the aggregate price level and the quantity of aggregate output demanded by households (C), businesses (I), the government (G) and the rest of the world (NX = EX – IM).
GDP = C + I + G + NX

4. The Aggregate Demand Curve
Aggregate price
level (GDP deflator,
2000 = 100)
A movement down the
AD curve leads to a lower
aggregate price level and
higher aggregate output.
1933
8.9
5.0
Figure Caption: Figure 14-1: The Aggregate Demand Curve
The aggregate demand curve shows the relationship between the aggregate price level and the quantity of aggregate output demanded. The curve is downward-sloping due to the wealth effect of a change in the aggregate price level and the interest rate effect of a change in the aggregate price level. Here, the total quantity of goods and services demanded at an aggregate price level of 8.9, the actual number for 1933, is $636 billion in 2000 dollars, the actual quantity of aggregate output demanded in According to our hypothetical curve, however, if the aggregate price level had been only 5.0, the quantity of aggregate output demanded would have been $950 billion.
Aggregate demand
curve, AD
636
950
Real GDP (billions of 2000 dollars) 4

5. The Aggregate Demand Curve: Downward Sloping – Two Reasons
Wealth effect of a change in the aggregate price level—a higher aggregate price level reduces the purchasing power of households’ wealth and reduces consumer spending.
Interest rate effect of a change in the aggregate price level—a higher aggregate price level reduces the purchasing power of households’ money holdings, leading to a rise in interest rates and a fall in investment spending and consumer spending.

6. Shifts of the Aggregate Demand Curve
The aggregate demand curve shifts because of:
changes in expectations
wealth
the stock of physical capital
government policies
fiscal policy
monetary policy

7. Shifts of the Aggregate Demand Curve
(a) Rightward Shift
(b) Leftward Shift
Decrease in aggregate demand
Aggregate price level
Aggregate price level
Increase in aggregate demand
Figure Caption: Figure 14.2: Shifts of the Aggregate Demand Curve
Panel (a) shows the effect of events that increase the quantity of aggregate output demanded at any given aggregate price level, such as improvements in business and consumer expectations or increased government spending. Such changes shift the aggregate demand curve to the right, from AD1 to AD2. Panel (b) shows the effect of events that decrease the quantity of aggregate output demanded at any given price level, such as a fall in wealth caused by a stock market decline. This shifts the aggregate demand curve leftward from AD1 to AD2. AD AD AD AD 1 2 2 1
Real GDP
Real GDP 7

8. Factors That Shift the Aggregate Demand Curve
Changes in expectations
If consumers and firms become more optimistic, …aggregate demand increases.
If consumers and firms become more pessimistic, aggregate demand decreases.
Changes in wealth
If the real value of household assets rises, ………..aggregate demand increases.
If the real value of household assets falls, ………..aggregate demand decreases.
Size of the existing stock of physical capital
If the existing stock of physical capital is relatively small, .. aggregate demand increases.
If the existing stock of physical capital is relatively large, ..aggregate demand decreases.
Fiscal policy
If the government increases spending or cuts taxes, aggregate demand increases.
If the government reduces spending or raises taxes, aggregate demand decreases.
Monetary policy
If the central bank increases the quantity of money, aggregate demand increases.
If the central bank reduces the quantity of money, aggregate demand decreases

9. Changes in Wealth: A Movement Along versus a Shift of the Aggregate Demand Curve
One reason AD curve slopes down is due to the wealth effect.
But we just explained that changes in wealth lead to a shift of the AD curve.
Aren’t those two explanations contradictory? Which one is it?
The answer is both: it depends on the source of the change in wealth.
A movement along the AD curve occurs when a change in the aggregate price level changes the purchasing power of consumers’ existing wealth (the real value of their assets).
This is the wealth effect of a change in the aggregate price level—a change in the aggregate price level is the source of the change in wealth.
A change in wealth independent of a change in price level shifts the aggregate demand curve.

10. Shifts of the Aggregate Demand Curve 2008-2009
When looking at the data it’s hard to tell the difference between a movement along the aggregate demand curve and a shift of the aggregate demand curve.
In 2008 it was crystal clear. Spending by households and firms fell which caused the aggregate demand curve to shift to the left. As a result, GDP fell by over 2%.
In response the Federal Reserve increased the quantity of money which lead to a decrease in interest rates (the prime rate fell from 7.5% in 2007 to 3.25% in 2008).
These moves resulted in the aggregate demand curve shifting again–to the right and GDP rose by 5.2% in 2009 and the CPI rose by 3.2%. Exactly the response we would expect.

11. a movement up along the aggregate demand curve.
A rise in the interest rate caused by a change in monetary policy causes:
a movement up along the aggregate demand curve.
a movement down along the aggregate demand curve.
a leftward shift of the aggregate demand curve.
a rightward shift of the aggregate demand curve.
A higher interest rate decreases investment and consumption at every price level, so the aggregate demand curve shifts to the left.

12. a movement up along the aggregate demand curve.
A fall in the real value of money in the economy due to a higher price level causes:
a movement up along the aggregate demand curve.
a movement down along the aggregate demand curve.
a leftward shift of the aggregate demand curve.
a rightward shift of the aggregate demand curve.
As the price level rises, the real value of money holdings falls. This is the interest rate effect of a change in the aggregate price level: as the value of money falls people want to hold more money, so they borrow more and lend less. This increases interest rates and reduces consumer and investment spending. So this is a movement along the aggregate demand curve.

13. Expectations of a poor job market next year causes:
a movement up along the aggregate demand curve.
a movement down along the aggregate demand curve.
a leftward shift of the aggregate demand curve.
a rightward shift of the aggregate demand curve.
The aggregate demand curve shifts to the left because expectations of a poor job market and lower incomes will reduce spending today.

14. A fall in tax rates causes:
a movement up along the aggregate demand curve.
a movement down along the aggregate demand curve.
a leftward shift of the aggregate demand curve.
a rightward shift of the aggregate demand curve.
Lower tax rates increases disposable income so that people can spend more at any price level, which shifts the aggregate demand curve to the right.

15. a movement up along the aggregate demand curve.
A rise in the real value of assets in the economy due to a lower price level causes:
a movement up along the aggregate demand curve.
a movement down along the aggregate demand curve.
a leftward shift of the aggregate demand curve.
a rightward shift of the aggregate demand curve.
As the price level falls, the real value of assets rises. This is the wealth effect of a change in the price level: as the value of assets rises, people will increase their consumption plans. This leads to higher consumption spending and a movement down the aggregate demand curve.

16. a movement (increase) along the aggregate demand curve.
A rise in the real value of assets in the economy due to a surge in real estate values causes:
a movement (increase) along the aggregate demand curve.
a movement (decrease) along the aggregate demand curve.
a leftward shift of the aggregate demand curve.
a rightward shift of the aggregate demand curve.
The aggregate demand curve shifts because an increase in the value of assets due to an increase in real estate values raises consumer spending at any price level.

17. Aggregate Supply
The aggregate supply curve shows the relationship between the aggregate price level and the quantity of aggregate output in the economy.

18. The Short-Run Aggregate Supply Curve
The short-run aggregate supply curve is upward-sloping because nominal wages are sticky in the short run:
a higher aggregate price level leads to higher profits and increased aggregate output in the short run.
The nominal wage is the dollar amount of the wage paid.
Sticky wages are nominal wages that are slow to fall even in the face of high unemployment and slow to rise even in the face of labor shortages.

19. The Short-Run Aggregate Supply Curve
supply curve, SRAS
Aggregate price
level (GDP deflator,
2000 = 100)
11.9
1929
A movement down
the SRAS curve leads
to deflation and lower
aggregate output.
8.9
1933
Figure Caption: Figure 14.3: The Short-Run Aggregate Supply Curve
The short-run aggregate supply curve shows the relationship between the aggregate price level and the quantity of aggregate output supplied in the short run, the period in which many production costs such as nominal wages are fixed. It is upward sloping because a higher aggregate price level leads to higher profit per unit of output and higher aggregate output given fixed nominal wages. Here we show numbers corresponding to the Great Depression, from 1929 to 1933: when deflation occurred and the aggregate price
level fell from 11.9 (in 1929) to 8.9 (in 1933), firms responded by reducing the quantity of aggregate output supplied from $865 billion to $636 billion measured in 2000 dollars.
636
865
Real GDP (billions of 2000 dollars) 19

20. What’s Truly Flexible, What’s Truly Sticky
Data on wages and prices is mixed.
Some nominal wages are flexible in the short run because some workers are not covered by a contract or agreement with employers.
Since some nominal wages are sticky but others are flexible, we observe that the average nominal wage—the nominal wage averaged over all workers in the economy—falls when there is a steep rise in unemployment.
On the other side, some prices of final goods and services are sticky rather than flexible. Some firms, particularly the makers of luxury or name-brand goods, are reluctant to cut prices even when demand falls. Instead they prefer to cut output even if their profit per unit hasn’t declined.
This doesn’t change the basic picture: the short-run aggregate supply curve is still upward sloping.

21. Shifts of the Short-Run Aggregate Supply Curve
(a) Leftward Shift
(b) Rightward Shift
Aggregate price level
Aggregate price level
SRAS
SRAS 1
SRAS 2
SRAS 2 1
Figure Caption: Figure 14.4: Shifts of the Short-Run Aggregate Supply Curve
Panel (a): A decrease in short-run aggregate supply: the short-run aggregate supply curve shifts leftward from SRAS1 to SRAS2, and the quantity of aggregate output supplied at any given aggregate price level falls.
Panel (b): An increase in short-run aggregate supply: the short-run aggregate supply curve shifts rightward from SRAS1 to SRAS2,and the quantity of aggregate output supplied at any given aggregate price level rises.
Decrease in short-run
aggregate supply
Increase in short-run
aggregate supply
Real GDP
Real GDP 21

22. Shifts of the Short-Run Aggregate Supply Curve
Changes in
commodity prices
nominal wages
productivity
lead to changes in producers’ profits and shift the short-run aggregate supply curve.

23. Factors that Shift Short-Run Aggregate Supply
Changes in commodity prices
If commodity prices fall, short-run aggregate supply increases.
If commodity prices rise, short-run aggregate supply decreases.
Changes in nominal wages
If nominal wages fall, short-run aggregate supply increases.
If nominal wages rise, short-run aggregate supply decreases.
Changes in productivity
If workers become more productive, short-run aggregate supply increases.
If workers become less productive, short-run aggregate supply decreases

24. Long-Run Aggregate Supply Curve
The long-run aggregate supply curve shows the relationship between the aggregate price level and the quantity of aggregate output supplied that would exist if all prices, including nominal wages, were fully flexible.
Potential output is the level of real GDP the economy would produce if all prices, including nominal wages, were fully flexible

25. Long-Run Aggregate Supply Curve
Aggregate price
level (GDP deflator,
2000 = 100)
Long-run aggregate
supply curve, LRAS
15.0
…leaves the quantity
of aggregate output
supplied unchanged
in the long run.
A fall in the
aggregate
price level…
7.5
Figure Caption: Figure 14.5: Long-Run Aggregate Supply Curve
The long-run aggregate supply curve shows the quantity of aggregate output supplied when all prices, including nominal wages, are flexible. It is vertical at potential output, YP , because in the long run an increase in the aggregate price level has no effect on the quantity of aggregate output supplied.
$800
Real GDP (billions of 2000 dollars)
Potential
output, YP 25

26. Actual and Potential Output from 1989 to 2010
Figure Caption: Figure 14-6: Actual and Potential Output from 1989 to 2007
This figure shows the performance of actual and potential output in the United States from 1989 to The black line shows estimates of U.S. potential output, produced by the Congressional Budget Office, and the blue line shows actual aggregate output. The purple-shaded years are periods in which actual aggregate output fell below potential output, and the green-shaded years are periods in which actual aggregate output exceeded potential output. As shown, significant shortfalls occurred in the recessions of the early 1990s and after Actual aggregate output was significantly above potential output in the boom of the late 1990s.
Source: Congressional Budget Office; Bureau of Economic Analysis. 26

27. Economic Growth Shifts the LRAS Curve Rightward
Notes to the Instructor: This figure is from the earlier edition.

28. From the Short Run to the Long Run
(a) Leftward Shift of the Short-Run
Aggregate Supply Curve
(b) Rightward Shift of the Short-Run
Aggregate Supply Curve
Aggregate price level
Aggregate price level L R AS L R AS S R AS S R AS 2
A fall in nominal
wages shifts SRAS rightward. 1 S R AS 2
A rise in nominal
wages shifts SRAS eftward. S R AS 1 A1 A1 P P
Figure Caption: Figure 14.7: From the Short Run to the Long Run
Panel (a): The initial short-run aggregate supply curve is SRAS1. At the aggregate price level, P1, the quantity of aggregate output supplied, Y1, exceeds potential output, YP. Eventually, low unemployment will cause nominal wages to rise, leading to a leftward shift of the short-run aggregate supply curve from SRAS1 to SRAS2.
Panel (b): At the aggregate price level, P1, the quantity of aggregate output supplied is less than potential output. 1 1 Y Y
Real GDP Y Y P 1 1 P
Real GDP 28

29. Are We There yet? What the Long Run Really Means
We’ve used the term long run in two different contexts. In an earlier chapter we focused on long-run economic growth: growth that takes place over decades.
In this chapter we introduced the long-run aggregate supply curve, which depicts the economy’s potential output: the level of aggregate output that the economy would produce if all prices, including nominal wages, were fully flexible.
It might seem that we’re using the same term, long run, for two different concepts. But we aren’t: these two concepts are really the same thing.
Because the economy always tends to return to potential output in the long run, actual aggregate output fluctuates around potential output, rarely getting too far from it. As a result, the economy’s rate of growth over long periods of time—say, decades—is very close to the rate of growth of potential output. And potential output growth is determined by the factors we analyzed in the chapter on long-run economic growth.
So that means that the “long run” of long-run growth and the “long run” of the long-run aggregate supply curve coincide.

30. Prices and Output During the Great Depression
Figure Caption: Figure 14.8: Prices and Output During the Great Depression
From 1929 to 1933, prices and aggregate output fell together. And from 1933 to 1937, prices and aggregate output rose together. That is, during the period of 1929 to 1937, the economy behaved as if it were first moving down and then up the short-run aggregate supply curve. By the late 1930s, however, aggregate output was above 1929 levels even though the aggregate price level was still lower than it was in This reflects the fact that the short-run aggregate supply curve had shifted to the right during this period, due to both the short-run adjustment process in the economy and to a rightward shift of the long-run aggregate supply curve. 30

31. A rise in CPI leads producers to increase output. This represents a:
shift in the SRAS curve.
movement along the SRAS curve.
This represents a movement along the SRAS curve because the CPI–like the GDP deflator–is a measure of the aggregate price level of final goods and services in the economy.

32. movement along the SRAS curve.
A fall in the price of oil leads producers to increase output. This represents a:
shift in the SRAS curve.
movement along the SRAS curve.
This represents a shift of the SRAS because oil is a commodity. The SRAS curve will shift to the right because production costs are lower now, leading to a higher quantity of output supplied at any given price level.

33. movement along the SRAS curve.
A rise in legally mandated retirement benefits paid to workers leads producers to reduce output. This represents a:
shift in the SRAS curve.
movement along the SRAS curve.
This represents a shift of the SRAS curve because it involves a change in nominal wages. An increase in benefits to workers is equivalent to an increase in nominal wages. As a result the SRAS curve will shift leftward because production costs are now higher, leading to a lower quantity of aggregate output supplied at any given aggregate price level.

34. movement along the SRAS curve.
Assume that an economy is initially at potential output. The aggregate output supplied increases due to an increase in aggregate price level. This represents a:
shift in the SRAS curve.
movement along the SRAS curve.
If the price level and the quantity of output supplied both increase, this is caused by a movement along the SRAS.

35. The AS–AD Model
The AS-AD model uses the aggregate supply curve and the aggregate demand curve together to analyze economic fluctuations.

36. Short-Run Macroeconomic Equilibrium
The economy is in short-run macroeconomic equilibrium when the quantity of aggregate output supplied is equal to the quantity demanded.
The short-run equilibrium aggregate price level is the aggregate price level in the short-run macroeconomic equilibrium.
Short-run equilibrium aggregate output is the quantity of aggregate output produced in the short-run macroeconomic equilibrium.

37. The AS–AD Model Aggregate price level
Short-run macroeconomic equilibrium P E E SR
Figure Caption: Figure 14.9: The AS–AD model
The AS–AD model combines the short-run aggregate supply curve and the aggregate demand curve. Their point of intersection, ESR , is the point of short-run macroeconomic equilibrium where the quantity of aggregate output demanded is equal to the quantity of aggregate output supplied. PE is the short-run equilibrium aggregate price level, and YE is the short-run equilibrium level of aggregate output. AD Y
Real GDP E 37

38. Shocks Demand Shock is an event that shifts the Aggregate Demand curve
Supply Shock is an event that shifts the short-run Aggregate Supply curve
Stagflation is the combination of inflation and falling aggregate output

39. Shifts of Aggregate Demand: Short-Run Effects
(a) A Negative Demand Shock
(b) A Positive Demand Shock
Aggregate price level
Aggregate price level Y 2 P AD
A negative demand shock... E P 2 Y AD
A positive demand shock... S R AS S R AS
...leads to a higher aggregate price level and higher aggregate output. P 1 E
...leads to a lower aggregate price level and lower aggregate output. 1 2
Figure Caption: Figure 14.10: Demand Shocks
A demand shock shifts the aggregate demand curve, moving the aggregate price level and aggregate output in the same direction. In panel (a) a negative demand shock shifts the aggregate demand curve leftward from AD1 to AD2, reducing the aggregate price level from P1 to P2 and aggregate output from Y1 to Y2. In panel (b) a positive demand shock shifts the aggregate demand curve rightward, increasing the aggregate price level from P1 to P2 and aggregate output from Y1 to Y2. P E E 1 1 AD 1 AD 1 Y Y 1
Real GDP 1
Real GDP 39

40. Shifts of the SRAS Curve
(a) A Negative Supply Shock
(a) A Positive Supply Shock
Aggregate price level
Aggregate price level
A positive supply shock...
A negative supply shock...
SRAS Y 2 E P
SRAS
SRAS P 2 Y
SRAS 1 1 E 1 P 1
...leads to a higher aggregate output and lower aggregate price level.
...leads to a lower aggregate output and a higher aggregate price level.
Figure Caption: Figure 28-13: Supply Shocks
A supply shock shifts the short-run aggregate supply curve, moving the aggregate price level and aggregate output in opposite directions.
Panel (a) shows a negative supply shock, which shifts the short-run aggregate supply curve leftward, causing stagflation—lower aggregate output and a higher aggregate price level. Here the short-run aggregate supply curve shifts from SRAS1 to SRAS2 , and the economy moves from E1 to E2. The aggregate price level rises from P1 to P2 , and aggregate output falls from Y1 to Y2.
Panel (b) shows a positive supply shock, which shifts the short-run aggregate supply curve rightward, generating higher aggregate output and a lower aggregate price level. The short-run aggregate supply curve shifts from SRAS1 to SRAS2 , and the economy moves from E1 to E2. The aggregate price level falls from P1 to P2 , and aggregate output rises from Y1 to Y2. An event that shifts the short-run aggregate supply curve is a supply shock. P E E 1 2 1 AD AD Y
Real GDP Y
Real GDP 1 1 40

41. The Supply Shock of
In the summer of 2007, for reasons that are still a matter of dispute, the prices of many raw materials sold on world markets began shooting up. By the middle of 2008, the price of oil had doubled, the price of rice had tripled, and there had been major increases in the prices of many other commodities, from wheat to iron ore. The surge in raw-material prices amounted to a global negative supply shock, affecting all economies. This figure shows the rate of inflation, as measured by the percentage increase in the consumer price index over the previous year, for five major economies from May 2007 to May The countries started from very different initial positions, ranging from 2.7% inflation in the United States to zero inflation in Japan. Yet all of the countries experienced a substantial jump in prices. 41

42. Long-Run Macroeconomic Equilibrium
The economy is in long-run macroeconomic equilibrium when the point of short-run macroeconomic equilibrium is on the long-run aggregate supply curve.

43. Long-Run Macroeconomic EquilibriumAS
Aggregate price level S R AS
Long-run macroeconomic equilibrium P E E LR
Figure Caption: Figure 14.12: Long-Run Macroeconomic Equilibrium
Here the point of short-run macroeconomic equilibrium also lies on the long-run aggregate supply curve, LRAS. As a result, actual aggregate output is equal to potential output. The economy is in long-run macroeconomic equilibrium at ELR. AD Y
Real GDP P
Potential output 43

44. Short-Run Versus Long-Run Effects of a Negative Demand Shock
2. …reduces the aggregate price level and aggregate output and leads to higher
unemployment in the short run…
Aggregate price level L R AS S R AS 1
SRAS 2 P E 1
1. An initial
negative
demand shock… 1
3. …until an eventual
fall in nominal wages
in the long run increases
short-run aggregate supply and moves the economy back to potential output. P 2 E 2
Figure Caption: Figure 14.13: Short-Run Versus Long-Run Effects of a Negative Demand Shock
In the long run the economy is self-correcting: demand shocks have only temporary effects on aggregate output. Starting at E1, a negative demand shock shifts AD1 leftward to AD2. In the short run the economy moves to E2 and a recessionary gap arises: the aggregate price level declines from P1 to P2, aggregate output declines from Y1 to Y2, and unemployment rises. But in the long run nominal wages fall in response to high unemployment, and SRAS1 shifts rightward to SRAS2: aggregate output rises from Y2 to Y1, and the aggregate price level declines again, from P2 to P3. Long-run macroeconomic equilibrium is eventually restored at E3. P 3 E 3 AD 1 AD 2 Y Y 2 1
Potential
output
Real GDP
Recessionary gap 44

45. Short-Run Versus Long-Run Effects of a Positive Demand ShockAS 2
3…until an eventual rise in nominal wages in the long run reduces short-run aggregate supply and moves the economy back to potential output. AD 2
An initial positive
demand shock… L R AS
Aggregate price level S R AS 1 E 3 P 3 E 2
2. …increases the
aggregate price level
and aggregate output
and reduces unemployment
in the short run… P
Figure Caption: Figure 14.14: Short-Run Versus Long-Run Effects of a Positive Demand Shock
Starting at E1 a positive demand shock shifts AD1 rightward to AD2, and the economy moves to E2 in the short run. This results in an inflationary gap as aggregate output rises from Y1 to Y2, the aggregate price level rises from P1 to P2, and unemployment falls to a low level. In the long run, SRAS1 shifts leftward to SRAS2 as nominal wages rise in response to low unemployment. Aggregate output falls back to Y1, the aggregate price level rises again to P3, and the economy returns to long-run macroeconomic equilibrium at E3. 2 E1 P 1 AD 1
Potential
output Y Y
Real GDP 1 2
Inflationary gap 45

46. Gap Recap
There is a recessionary gap when aggregate output is below potential output.
There is an inflationary gap when aggregate output is above potential output.
The output gap is the percentage difference between actual aggregate output and potential output.

47. Gap Recap
The economy is self-correcting when shocks to aggregate demand affect aggregate output in the short run, but not the long run.

48. Where’s the Deflation?
The AD–AS model says that either a negative demand shock or a positive supply shock should lead to a fall in the aggregate price level—that is, deflation. In fact, however, the United States hasn’t experienced an actual fall in the aggregate price level since 1949.
What happened to the deflation?
The basic answer is that since World War II economic fluctuations have taken place around a long-run inflationary trend. Before the war, it was common for prices to fall during recessions, but since then negative demand shocks have been reflected in a decline in the rate of inflation rather than an actual fall in prices.
A very severe negative demand shock could still bring deflation, which is what happened in Japan.

49. Negative Supply Shocks
Negative supply shocks pose a policy dilemma: a policy that stabilizes aggregate output by increasing aggregate demand will lead to inflation, but a policy that stabilizes prices by reducing aggregate demand will deepen the output slump.

50. Negative Supply Shocks Are Relatively Rare but Nasty
Figure Caption: Figure 14.15: Negative Supply Shocks Are Relatively Rare but Nasty
Only two of eleven postwar recessions seem to fit the profile of a recession caused by a negative supply shock: the recession that followed the increase in oil prices after the 1973 Arab–Israeli war and the recession that followed another surge in oil prices after the Iranian revolution. These two recessions were, however, the worst in terms of unemployment. A third recession that began in December 2007 was at least partially caused by a spike in oil prices. By October of 2009, unemployment reached 10%. 50

51. Supply Shocks versus Demand Shocks in Practice
Recessions are mainly caused by demand shocks. But when a negative supply shock does happen, the resulting recession tends to be particularly severe.
There’s a reason the aftermath of a supply shock tends to be particularly severe for the economy: macroeconomic policy has a much harder time dealing with supply shocks than with demand shocks.
The reason the Federal Reserve was having a hard time in 2008, as described in the opening story, was the fact that in early 2008 the U.S. economy was in a recession partially caused by a supply shock (although it was also facing a demand shock).

52. increase; increase decrease; decrease increase; decrease
The government sharply increases the minimum wage, raising the wages of many workers. This causes a(n) ______ in output as measured by real GDP and a(n) ______ in the price level.
increase; increase
decrease; decrease
increase; decrease
decrease; increase
An increase in the minimum wage raises the nominal wage and shifts the short-run aggregate supply curve to the left. As a result of this negative supply shock, output decreases and the price level increases.

53. increase; increase decrease; decrease increase; decrease
Telecommunications companies launch a major program of investment spending. This causes a(n) ______ in output as measured by real GDP and a(n) ______ in the price level.
increase; increase
decrease; decrease
increase; decrease
decrease; increase
Increased investment increases aggregate demand, which causes an increase in output and the price level.

54. Congress raises taxes and cuts spending
Congress raises taxes and cuts spending. This causes a(n) ______ in output as measured by real GDP and a(n) ______ in the price level.
increase; increase
decrease; decrease
increase; decrease
decrease; increase
Higher taxes and less government spending decreases aggregate demand, which causes a decrease in both output and the price level.

55. Severe weather destroys crops around the world
Severe weather destroys crops around the world. This causes a(n) ______ in output as measured by real GDP and a(n) ______ in the price level.
increase; increase
decrease; decrease
increase; decrease
decrease; increase
This is a negative supply shock which decreases short-run aggregate supply. The decrease in SRAS decreases output and increases the price level.

56. True or False? A rise in productivity increases potential output, but demand for the additional output will be insufficient in the long run.
True
False
As long-run growth increases potential output, the long-run aggregate supply curve shifts to the right. If, in the short run, there is now a recessionary gap, nominal wages will fall, shifting the SRAS to the right. As prices fall, we move down the aggregate demand curve until actual output is equal to potential output

57. Macroeconomic Policy Economy is self-correcting in the long run.
Most economists think it takes a decade or longer!!!
John Maynard Keynes: “In the long run we are all dead.”
Stabilization policy is the use of government policy to reduce the severity of recessions and rein in excessively strong expansions.
Notes to the Instructor: There can be drawbacks, however, because such deficit and erroneous predictions can increase economic policies that may contribute to a long-term rise in the budget instability.

58. Keynes and the Long Run
The British economist Sir John Maynard Keynes (1883–1946), probably more than any other single economist, created the modern field of macroeconomics.
In 1923 Keynes published A Tract on Monetary Reform, a small book on the economic problems of Europe after World War I.
In it he decried the tendency of many of his colleagues to focus on how things work out in the long run:
“This long run is a misleading guide to current affairs. In the long run we are all dead. Economists set themselves too easy, too useless a task if in tempestuous seasons they can only tell us that when the storm is long past the sea is flat again.”

59. Macroeconomic Policy
The high cost—in terms of unemployment—of a recessionary gap and the future adverse consequences of an inflationary gap  Active stabilization policy, using fiscal or monetary policy to offset shocks.

60. Macroeconomic Policy Policy in the face of supply shocks:
There are no easy policies to shift the short-run aggregate supply curve.
Policy dilemma: a policy that counteracts the fall in aggregate output by increasing aggregate demand will lead to higher inflation, but a policy that counteracts inflation by reducing aggregate demand will deepen the output slump.

61. Is Stabilization Policy Stabilizing?
Has the economy actually become more stable since the government began trying to stabilize it?
Yes. Data from the pre-World War II era are less reliable than more modern data, but there still seems to be a clear reduction in the size of economic fluctuations.
It’s possible that the greater stability of the economy reflects good luck rather than policy.
But on the face of it, the evidence suggests that stabilization policy is indeed stabilizing.

62. “Expansionary monetary or fiscal policy does nothing but temporarily over stimulate the economy—you have a brief high, but then you have the pain of inflation.” Which statement below best describes how the AS-AD model represents this statement?
The policy causes the AD curve to shift to the right, causing aggregate price and output to rise. After a period of time nominal wages rise, shifting the AS curve to the left until output falls back to potential output.
The policy causes a movement along the AD curve which increases prices. After time the prices fall back to their initial levels.
The policy causes the AS curve to shift to the right causing prices and output to rise. After a period of time nominal wages rise and output falls back to potential output but prices remain elevated.
If expansionary monetary or fiscal policy is implemented when the economy is in long-run macroeconomic equilibrium, then aggregate demand increases to create an inflationary gap, with higher output and prices. Eventually nominal wages will increase and shift the SRAS to the left, returning output to potential output.

63. True or False? In 2008, after the collapse of the housing bubble and the sharp rise in the price of commodities, especially oil, the appropriate policy for the Fed was to lower interest rates.
True
False
Uncertain
Those within the Fed who advocated lowering interest rates were focused on boosting aggregate demand in order to counteract the negative demand shock caused by the collapse of the housing bubble. Lowering interest rates will result in a rightward shift of the aggregate demand curve, increasing aggregate output, but raising the aggregate price level. Those within the Fed who advocated holding interest rates steady were focused on the fact that fighting the slump in aggregate demand in the face of a negative supply shock could result in a rise in inflation. Holding interest rates steady relies on the ability of the economy to self-correct in the long run, with the aggregate price level and aggregate output only gradually returning to their levels before the negative supply shock.

64. Summary
1 of 4
The aggregate demand curve is the relationship between aggregate price level and quantity of aggregate output demanded.
The aggregate demand curve is downward sloping because of the wealth effect–a higher aggregate price level reduces the purchasing power of households’ wealth and reduces consumer spending and the interest rate effect–a higher aggregate price level reduces the purchasing power of households’ and firms’ money holdings, leading to a rise in interest rates and a fall in investment spending and consumer spending.
The aggregate demand curve shifts because of changes in expectations, changes in wealth and the effect of the size of the existing stock of physical capital. Policy makers can use fiscal policy and monetary policy to shift the aggregate demand curve.

65. Summary
2 of 4
The aggregate supply curve is the relationship between the aggregate price level and the quantity of aggregate output supplied.
The short-run aggregate supply curve is upward sloping because nominal wages are sticky in the short run.
Changes in commodity prices, nominal wages, and productivity lead to changes in producers’ profits and shift the short-run aggregate supply curve.
In the long run, all prices are flexible and the economy produces at its potential output. So the long-run aggregate supply curve is vertical at potential output.

66. Summary
3 of 4
The intersection of the short-run aggregate supply curve and the aggregate demand curve is the short-run macroeconomic equilibrium which determines short-run equilibrium aggregate price level and short-run equilibrium aggregate output.
Economic fluctuations occur because of a shift of the aggregate demand curve (a demand shock) or the short-run aggregate supply curve (a supply shock). A particularly nasty occurrence is stagflation—inflation and falling aggregate output—which is caused by a negative supply shock.

67. Summary
4 of 4
A recessionary gap is when aggregate output is less than potential output. An inflationary gap is when aggregate output is greater than potential output.
The high cost—in terms of unemployment—of a recessionary gap and the future adverse consequences of an inflationary gap lead many economists to advocate active stabilization policy: using fiscal or monetary policy to offset demand shocks.
Negative supply shocks pose a policy dilemma: a policy that counteracts the fall in aggregate output by increasing aggregate demand will lead to higher inflation, but a policy that counteracts inflation by reducing aggregate demand will deepen the output slump.