THE AGGREGATE DEMAND CURVE:Shifting the Aggregate Demand Curve

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Money & Banking MGT411

Lesson 42

THE AGGREGATE DEMAND CURVE

The slope of the aggregate demand curve tells us how sensitive current output is to a given

change in current inflation.

The aggregate demand curve will be relatively

Flat if current output is very sensitive to inflation (a change in current inflation causes a large

movement in current output)

Steep if current output is not very sensitive to inflation

Three factors influence the sensitivity of current output to inflation:

The strength of the effect of inflation on real money balances,

The extent to which monetary policymakers react to a change in current inflation,

The size of the response of aggregate demand to changes in the interest rate

The second factor relates to the slope of the monetary policy reaction curve

If policymakers react aggressively to a movement of current inflation away from its target level

with a large change in the real interest rate, the monetary policy reaction curve will be steep and

the aggregate demand curve is flat

If policymakers respond more cautiously, the monetary policy reaction curve is flat and the

aggregate demand curve is steep

The slope of the aggregate demand curve depends in part on the preferences of the central bank;

how aggressive policymakers are in responding to deviations of inflation from the target level

There are two reasons why the aggregate demand curve slopes down:

First, because higher inflation reduces real money balances (thus reducing purchases),

Second, because higher inflation induces policymakers to raise the real interest rate, depressing

various components of aggregate demand

Rising inflation also reduces wealth, which lowers consumption and drives down aggregate

demand.

In addition, as inflation rises the uncertainty about inflation rises, which makes equities a more

risky investment and drops their value, also reducing wealth

Another reason is that inflation can have a greater impact on the poor than it does on the

wealthy, redistributing income to those who are better off

People may also save more as a result of the increased risk associated with inflation.

Also, rising inflation makes foreign goods cheaper in relation to domestic goods, driving

imports up and net exports down.

Shifting the Aggregate Demand Curve

In our derivation of the aggregate demand curve, we held constant both the location of the

monetary policy reaction curve and those components of aggregate demand that do not respond

to the real interest rate.

Changes in any of those components, as well as changes in the location of the monetary policy

reaction curve, will shift the aggregate demand curve.

Shifts in the Monetary Policy Reaction Curve

Whenever the monetary policy reaction curve shifts, the aggregate demand curve will shift as

well

Changes in the long-run real interest rate, which is a consequence of the structure of the

economy, will also shift aggregate demand

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Money & Banking MGT411

Figure: Shifting the Aggregate Demand Curve (ADC)

Increases in aggregate Demand arising from a change in monetary policy, such as a higher

inflation target, will shift the aggregate demand curve to the right. Increases in interest rate

intensive components of aggregate demand, such as government purchases, will also shift the

aggregate demand curve to the right.

Inflation (š)

New ADC

Old ADC

Output (Y)

Either a fall in target inflation or a rise in the long-run real interest rate will shift the monetary

policy reaction curve to the left and the aggregate demand curve to the left.

Changes in the Components of Aggregate Demand

Any change in a component of aggregate demand that is caused by a factor other than a change

in the real interest rate will shift the aggregate demand curve.

When firms become more optimistic about the future, or consumer confidence increases,

investment or consumption will increase and aggregate demand will shift to the right.

Changes in the Components of Aggregate Demand

Increases in government purchases will increase aggregate demand, as will decreases in taxes.

Increases in net exports that are unrelated to changes in real interest rates will shift the

aggregate demand curve to the right

Changes that shift the Components of Aggregate Demand to the right:

An increase in consumption that is unrelated to a change in the real interest rate.

An increase in investment that is unrelated to a change in the real interest rate.

An increase in government purchases

A decrease in taxes

An increase in net exports that is unrelated to a change in the real interest rate

Because shifts in the monetary policy reaction curve can shift the aggregate demand curve, it is

possible that monetary policy can cause recessions.

If policymakers can cause recessions, they can probably avoid them as well by neutralizing

shifts in aggregate demand that arise from other sources.

The analysis up to this point has assumed that inflation does not change over time; but in reality

Inflation and output are jointly determined, and monetary policy plays a role in the short-run

Movements of both.

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