Lecture 10
28.4.2015
The Influence of
Monetary and Fiscal
Policy on Aggregate
Demand
Copyright © 2004 South-Western
Previous Lecture
• Short Run Economic Fluctuations
• Short Run vs. Long Run
• The classical dichotomy and monetary neutrality
• the economy’s output (real GDP) & the price level (CPI or GDP
deflator)
• Aggregate Demand Curve
• the 4 components of GDP – Y=C+G+I+NX
• Aggregate Supply Curve – Factors of Production
• In the long run – vertical curve
• In the short run – the price level (3 theories)
• 2 Causes of Economic Fluctuations
• Shifts in aggregate demand & shifts in aggregate supply
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Outline
• How do government’s policy influence the
aggregate demand curve?
• Monetary policy – the money supply set by a CB
• Fiscal policy – the level of government spending
and taxation set by government
• Macroeconomic variables in the SHORT RUN
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Aggregate Demand
• Many factors influence aggregate demand
besides monetary and fiscal policy.
• In particular, desired spending by households
and business firms determines the overall
demand for goods and services.
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HOW MONETARY POLICY
INFLUENCES AGGREGATE DEMAND
• The aggregate demand curve slopes downward
for three reasons:
• The wealth effect
• The interest-rate effect
• The exchange-rate effect
• For the U.S. economy, the most important
reason for the downward slope of the
aggregate-demand curve is the interest-rate
effect.
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The Theory of Liquidity Preference
• Keynes developed the theory of liquidity
preference in order to explain what factors
determine the economy’s interest rate.
• According to the theory, the interest rate adjusts
to balance the supply and demand for money.
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The Theory of Liquidity Preference
• Money Supply
• The money supply is controlled by CB through:
• Open-market operations
• Changing the reserve requirements
• Changing the discount rate
• Because it is fixed by the Fed, the quantity of
money supplied does not depend on the interest
rate.
• The fixed money supply is represented by a vertical
supply curve.
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The Theory of Liquidity Preference
• Money Demand
• Money demand is determined by several factors.
• People choose to hold money instead of other assets that
offer higher rates of return because money can be used to
buy goods and services.
• According to the theory of liquidity preference, one of
the most important factors is the interest rate.
• The opportunity cost of holding money is the interest that
could be earned on interest-earning assets.
• An increase in the interest rate raises the opportunity cost
of holding money.
• As a result, the quantity of money demanded is reduced.
Figure 1 Equilibrium in the Money Market
Quantity of
Money
Interest
Rate
0
Money
demand
Quantity fixed
by the Fed
Money
supply
r2
M2
d
Md
r1
Equilibrium
interest
rate
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Copyright © 2004 South-Western
The Theory of Liquidity Preference
• Equilibrium in the Money Market
• Assume the following about the economy:
• The price level is stuck at some level.
• For any given price level, the interest rate adjusts to
balance the supply and demand for money.
• The level of output responds to the aggregate demand for
goods and services.
Figure 2 The Money Market and the Slope of the
Aggregate-Demand Curve
Quantity
of Money
Quantity fixed
by the Fed
0
Interest
Rate
Money demand at
price level P2, MD2
Money demand at
price level P , MD
Money
supply
(a) The Money Market (b) The Aggregate-Demand Curve
3. . . .
which
increases
the
equilibrium
interest
rate . . .
2. . . . increases the
demand for money . . .
Quantity
of Output
0
Price
Level
Aggregate
demand
P2
Y2 Y
P
4. . . . which in turn reduces the quantity
of goods and services demanded.
1. An
increase
in the
price
level . . .
r
r2
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Copyright © 2004 South-Western
The Analysis of Interest Rate Effect
• A higher price level increases the quantity of
money demanded for any given interest rate.
• Higher money demand leads to a higher interest
rate.
• The quantity of goods and services demanded
falls.
• The end result of this analysis is a negative
relationship between the price level and the
quantity of goods and services demanded.
Figure 3 A Monetary Injection
MS2Money
supply,
MS
Aggregate
demand,AD
YY
P
Money demand
at price levelP
AD2
Quantity
of Money
0
Interest
Rate
r
r2
(a) The Money Market (b) The Aggregate-Demand Curve
Quantity
of Output
0
Price
Level
3. . . . which increases the quantity of goods
and services demanded at a given price level.
2. . . . the
equilibrium
interest rate
falls . . .
1. When the Fed
increases the
money supply . . .
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Copyright © 2004 South-Western
Changes in the Money Supply
• When the Fed increases the money supply, it
lowers the interest rate and increases the
quantity of goods and services demanded at any
given price level, shifting aggregate-demand to
the right.
• When the Fed contracts the money supply, it
raises the interest rate and reduces the quantity
of goods and services demanded at any given
price level, shifting aggregate-demand to the
left.
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The Role of Interest-Rate Targets in Fed
Policy
• Monetary policy can be described either in
terms of the money supply or in terms of the
interest rate.
• A target for the federal funds rate affects the
money market equilibrium, which influences
aggregate demand.
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HOW FISCAL POLICY INFLUENCES
AGGREGATE DEMAND
• Fiscal policy refers to the government’s choices
regarding the overall level of government
purchases or taxes.
• Fiscal policy influences saving, investment, and
growth in the long run.
• In the short run, fiscal policy primarily affects
the aggregate demand.
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Changes in Government Purchases
• When policymakers change the money supply
or taxes, the effect on aggregate demand is
indirect—through the spending decisions of
firms or households.
• When the government alters its own purchases
of goods or services, it shifts the aggregatedemand
curve directly.
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Changes in Government Purchases
• There are two macroeconomic effects from the
change in government purchases:
• The multiplier effect
• The crowding-out effect
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The Multiplier Effect
• Government purchases are said to have a
multiplier effect on aggregate demand.
• Each dollar spent by the government can raise the
aggregate demand for goods and services by more
than a dollar.
• The multiplier effect refers to the additional
shifts in aggregate demand that result when
expansionary fiscal policy increases income and
thereby increases consumer spending.
Figure 4 The Multiplier Effect
Quantity of
Output
Price
Level
0
Aggregate demand, AD1
$20 billion
AD2
AD3
1. An increase in government purchases
of $20 billion initially increases aggregate
demand by $20 billion . . .
2. . . . but the multiplier
effect can amplify the
shift in aggregate
demand.
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Copyright © 2004 South-Western
A Formula for the Spending Multiplier
• The formula for the multiplier is:
Multiplier = 1/(1 - MPC)
• An important number in this formula is the
marginal propensity to consume (MPC).
• It is the fraction of extra income that a household
consumes rather than saves.
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A Formula for the Spending Multiplier
• If the MPC is 3/4, then the multiplier will be:
Multiplier = 1/(1 - 3/4) = 4
• In this case, a $20 billion increase in
government spending generates $80 billion of
increased demand for goods and services.
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The Crowding-Out Effect
• Fiscal policy may not affect the economy as
strongly as predicted by the multiplier.
• An increase in government purchases causes
the interest rate to rise.
• A higher interest rate reduces investment
spending.
Figure 5 The Crowding-Out Effect
Quantity
of Money
Quantity fixed
by the Fed
0
Interest
Rate
r
Money demand, MD
Money
supply
(a) The Money Market
3. . . . which
increases
the
equilibrium
interest
rate . . .
2. . . . the increase in
spending increases
money demand . . .
MD2
Quantity
of Output
0
Price
Level
Aggregate demand, AD1
(b) The Shift in Aggregate Demand
4. . . . which in turn
partly offsets the
initial increase in
aggregate demand.
AD2
AD3
1. When an increase in government
purchases increases aggregate
demand . . .
r2
$20 billion
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Copyright © 2004 South-Western
The Crowding-Out Effect
• When the government increases its purchases
by $20 billion, the aggregate demand for goods
and services could rise by more or less than $20
billion, depending on whether the multiplier
effect or the crowding-out effect is larger.
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Changes in Taxes
• When the government cuts personal income
taxes, it increases households’ take-home pay.
• Households save some of this additional income.
• Households also spend some of it on consumer
goods.
• Increased household spending shifts the aggregatedemand
curve to the right.
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Changes in Taxes
• The size of the shift in aggregate demand
resulting from a tax change is affected by the
multiplier and crowding-out effects.
• It is also determined by the households’
perceptions about the permanency of the tax
change.
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USING POLICY TO STABILIZE
THE ECONOMY
• The Case for Active Stabilization Policy
• The government should avoid being the cause of
economic fluctuations.
• The government should respond to changes in the
private economy in order to stabilize aggregate
demand.
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The Case against Active Stabilization Policy
• Some economists argue that monetary and
fiscal policy destabilizes the economy.
• They suggest the economy should be left to
deal with the short-run fluctuations on its own.
• Monetary and fiscal policy affect the economy
with a substantial lag.
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Automatic Stabilizers
• Automatic stabilizers are changes in fiscal
policy that stimulate aggregate demand when
the economy goes into a recession without
policymakers having to take any deliberate
action.
• Automatic stabilizers include the tax system
and some forms of government spending.
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Summary
• Keyness – theory of liquidity
• Interest rate adjusts to balance the supply and demand for
money
• The analysis of interest rate effect – 3 steps:
• A higher price level increases the quantity of money
demanded for any given interest rate.
• Higher money demand leads to a higher interest rate.
• The quantity of goods and services demanded falls.
• Movements along AD curve
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Summary
• How monetary policy influences aggregate
demand
• Shifts in AD curve
• An increase in the money supply
• Shifts money supply curve to the right
• Interest rate must fall to induce people to hold additional
money that CB created
• The costs of borrowing and the return to saving are
reduced
• The demand for goods and services at given price level
increase
• The aggregate-demand curve shifts to the right.
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Summary
• How monetary policy influences aggregate
demand
• An increase in government purchases or a cut in
taxes shifts the aggregate-demand curve to the right.
• The shift in aggregate demand can be larger or
smaller than the fiscal change.
• 2 effects:
• The multiplier effect tends to amplify the effects of fiscal
policy on aggregate demand
• The crowding-out effect tends to dampen the effects of
fiscal policy on aggregate demand.
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Next Lecture
• How are inflation and unemployment related to
each other?
• In the long run - largely unrelated
• In the short run – the inflation-unemployment tradeoff
(the Phillips curve)