Title: Output and the Exchange Rate in the Short Run
1Output and the Exchange Rate in the Short Run
- Chapter 17 Krugman and Obstfeld 9e
- ECO41 International Economics
- Udayan Roy
2Long Run and Short Run
- Long run theories are useful when all prices of
inputs and outputs have enough time to adjust
fully to changes in supply and demand. - In the short run, some prices of inputs and
outputs may not have time to adjust, due to labor
contracts, costs of adjustment, or imperfect
information about market demand. - This chapter discusses a theory of the short run
behavior of a small economy with flexible
exchange rates under perfect capital mobility
3The DD curve
4Determinants of Aggregate Demand
- Aggregate demand (D) is the aggregate amount of
goods and services that people are willing to
buy. It consists of the following types of
expenditure - consumption expenditure (C)
- investment expenditure (I)
- government purchases (G)
- net expenditure by foreigners the current
account (CA)
5Determinants of Aggregate Demand
- Consumption expenditure (C) depends on Disposable
Income (Y-T), which is income (Y) minus taxes
(T). - More disposable income means more consumption
expenditure - But consumption typically increases less than the
amount by which disposable income increases. - Real interest rates may influence the amount of
saving and consumption, but we assume that they
are relatively unimportant here. - Wealth may also influence consumption, but we
assume that it is relatively unimportant here.
6Determinants of Aggregate Demand
- The current account (CA) depends on
- Real exchange rate (q), which is the price of
foreign products relative to the price of
domestic products q EP/P - As q rises, expenditure on domestic products
rises and expenditure on foreign products falls.
Therefore, when q rises, CA rises as well. - Disposable income more disposable income (Y-T)
means more expenditure on foreign products
(imports). Therefore, when Y-T rises, CA falls.
7Determinants of Aggregate Demand
- Determinants of the current account include
- Real exchange rate an increase in the real
exchange rate increases the current account. - Disposable income an increase in the disposable
income decreases the current account.
8Determinants of Aggregate Demand (cont.)
- For simplicity, we assume that exogenous
political factors determine government purchases
(G) and the level of taxes (T). - For simplicity, we assume that investment
expenditure (I) is also determined exogenously by
business sentiment. - A more complex model might assume that investment
depends on the cost of borrowing for investment,
the interest rate.
9Determinants of Aggregate Demand (cont.)
- Aggregate demand is therefore expressed as
- D C(Y T) I G CA(EP/P, Y T)
- Or more simply
- D D(EP/P, Y T, I, G)
10Determinants of Aggregate Demand (cont.)
- Determinants of aggregate demand include
- Real exchange rate an increase in the real
exchange rate increases the current account, and
therefore increases aggregate demand for domestic
products. - Disposable income an increase in the disposable
income increases consumption, but decreases the
current account. - Since total consumption expenditure is usually
greater than expenditure on foreign products, the
first effect dominates the second effect.
Therefore, - When disposable income increases, aggregate
demand increases, but by less than the increase
in disposable income. - Therefore, when income increases or taxes
decrease (or both), aggregate demand increases.
11Determinants of Aggregate Demand (cont.)
- Determinants of aggregate demand include
- Government Spending an increase in government
spending (G) increases aggregate demand for
domestic products (D). - Business Investment an increase in business
investment (I) increases aggregate demand (D).
12Short Run Equilibrium for Aggregate Demand and
Output
- Equilibrium is achieved when the value of output
Y equals aggregate demand D. - Y D(EP/P, Y T, I, G)
13Fig. 17-2 The Determination of Output in the
Short Run
Output is greater than aggregate demand
firms decrease output
Aggregate demand is greater than production
firms increase output
14Short Run Equilibrium and the Exchange Rate DD
Schedule
- How does the value of the foreign currency (E)
affect the short run equilibrium of aggregate
demand and output? - Domestic and foreign price levels (P and P) are
assumed fixed in the short run. - Therefore, a rise in the nominal exchange rate
(E) makes foreign goods more expensive relative
to domestic goods. That is, q E P/P
increases when E increases. - As a result, CA increases and, therefore, D
increases. That is, D increases when E increases.
See Fig 17-3. - In equilibrium, Y D. Therefore, Y increases
when E increases. - This gives the DD curve. See Fig 17-4.
Y D(EP/P, Y T, I, G)
15Fig. 17-3 Output Effect of a Currency
Depreciation with Fixed Output Prices
Y D(EP/P, Y T, I, G)
16Fig. 17-4 Deriving the DD Schedule
Y D(EP/P, Y T, I, G)
17Shifting the DD Curve
- Changes in the exchange rate cause movements
along a DD curve. Other changes may cause it to
shift - Changes in G more government purchases cause
higher aggregate demand and output in
equilibrium. Output increases for every exchange
rate the DD curve shifts right.
18Fig. 17-5 Government Demand and the Position of
the DD Schedule
An increase in G causes the DD curve to shift to
the right.
- The same rightward shift of the DD curve happens
if - I increases
- T decreases
- P/P increases
Y D(EP/P, Y T, I, G)
19Shifting the DD Curve
- The DD curve shifts right if
- G increases
- T decreases
- I increases
- P decreases
- P increases
- C increases for some unknown reason
- CA increases for some unknown reason
Y D(EP/P, Y T, I, G)
20The aa curve
21Short Run Equilibrium for Assets
- We consider two asset markets when considering
asset market equilibrium - Ch 14 Foreign exchange market
- interest parity R R (Ee E)/E
- Ch 15 Money market
- real money supply and demand determine
equilibrium Ms/P L(R, Y)
22What makes the value of the euro (E) change?
Note the inverse relation between Y and E. This
yields another curve linking Y and E the AA
curve.
M/P
(-)
()
R
Y
(-)
Domestic preference for cash
()
E
()
(-)
M/P
R
()
Y
()
Ee
()
Foreign preference for cash
23Fig. 17-7 The AA Schedule
24Recap What makes (E), the value of the foreign
currency, change?
Note the inverse relation between Y and E. This
yields another curve linking Y and E the AA
curve.
M/P
(-)
()
R
Y
But E is also affected by changes in M/P, Ee, and
L, the preference for cash.
(-)
Domestic preference for cash
()
E
()
(-)
M/P
R
()
Y
()
Ee
()
Foreign preference for cash
25Shifting the AA Curve
- The AA curve shifts right if
- Ms increases
- P decreases
- Ee rises
- R rises
- L decreases for some unknown reason
E
E0
E1
Y
Y0
Y1
26Short-run macroeconomic equilibrium
27Putting the Pieces Together the DD and AA Curves
- A short run equilibrium means that the exchange
rate (E) and output (Y) are such that there is
equilibrium in - the output market aggregate demand (D) equals
aggregate output (Y). - the foreign exchange market interest parity
holds. - the money market real money supply (MS/P) equals
real money demand (L).
Y D(EP/P, Y T, I, G)
28Fig. 17-8 Short-Run Equilibrium The
Intersection of DD and AA
The short run equilibrium occurs at the
intersection of the DD and AA curves
The output market is in equilibrium on the DD
curve
The asset markets are in equilibrium on the DD
curve
29Shifting the AA and DD Curves
- The AA curve shifts right if
- Ms increases
- P decreases
- Ee rises
- R rises
- L decreases for some unknown reason
- The DD curve shifts right if
- G increases
- T decreases
- I increases
- P decreases
- P increases
- C increases for some unknown reason
- CA increases for some unknown reason
30Short-run effects of temporary changes in
government policy
31Temporary Changes in Monetary and Fiscal Policy
- Monetary policy policy in which the central bank
influences the money supply (MS). - Monetary policy primarily influences asset
markets. - Fiscal policy policy in which governments
influence the amount of government purchases (G)
and taxes (T). - Fiscal policy primarily influences aggregate
demand (D). - Temporary policy changes are expected to be
reversed in the near future and thus do not
affect expectations about exchange rates in the
long run. Specifically, temporary changes in MS,
G, and T do not affect Ee.
32Shifting the AA and DD Curves
- The AA curve shifts right if
- Ms increases
- P decreases
- Ee rises
- R rises
- L decreases for some unknown reason
- The DD curve shifts right if
- G increases
- T decreases
- I increases
- P decreases
- P increases
- C increases for some unknown reason
- CA increases for some unknown reason
33Temporary Changes in Monetary Policy
- When there is an increase in the supply of money
- The AA shifts up (right).
- Both E and Y increase
- R decreases
- As Ee is unaffected when the change in Ms is
temporary, the increase in E leads to a decrease
in R recall R R (Ee E)/E.
E
DD
E0
Y
Y0
34Fig. 17-10 Effects of a Temporary Increase in
the Money Supply
R? and Ee ? have the same effect, as does a fall
in money demand (L).
35Effect of temporary MS? on CA
- Goods market equilibrium (DD curve) Y C(Y
T) I G CA. - An increase in Ms causes Y to increase. But C(Y
T) increases less than Y does. Therefore, CA must
increase. - That is, an increase in the supply of money,
leads to an increase in the current account
balance (or, net exports)
36Temporary Changes in Fiscal Policy
- An increase in government purchases or a decrease
in taxes increases aggregate demand and output. - The DD curve shifts right.
- Higher output increases real money demand, and
- thereby increases interest rates,
- causing an increase in the value of the domestic
currency (a fall in E).
37Shifting the AA and DD Curves
- The AA curve shifts right if
- Ms increases
- P decreases
- Ee rises
- R rises
- L decreases for some unknown reason
- The DD curve shifts right if
- G increases
- T decreases
- I increases
- P decreases
- P increases
- C increases for some unknown reason
- CA increases for some unknown reason
38Fig. 17-11 Effects of a Temporary Fiscal
Expansion G ? and/or T ?
P? and I? have the same effect, as do shocks
that increase C and CA. E? implies R? because R
R Ee/E - 1.
39Effect of G? and/or T? on CA
- When G? and/or T? this is called expansionary
fiscal policy E? and Y?. - Therefore, CA?.
- Expansionary (contractionary) fiscal policy
reduces (increases) net exports.
40Fig. 17-12 Maintaining Full Employment After a
Temporary Fall in World Demand for Domestic
Products
Temporary fall in world demand for domestic
products reduces output below its normal level
Temporary monetary expansion could depreciate
the domestic currency
Temporary fiscal policy could reverse the fall
in aggregate demand and output
41Fig. 17-13 Policies to Maintain Full Employment
After a Money Demand Increase
Temporary monetary policy could increase money
supply to match money demand
Increase in money demand raises interest rates
and appreciates the domestic currency
Temporary fiscal policy could increase aggregate
demand and output
42Short-run effects of permanent changes in
government policy
43Permanent Changes in Monetary and Fiscal Policy
- Permanent policy changes modify peoples
expectations about future exchange rates (Ee) - when they change the long-run value of Ef.
44Permanent Increase in Money Supply
- The AA curve shifts right because of the increase
in MS. The equilibrium moves from point 1 to
point 3 in Fig 17-14. - In the long run, E will rise. See Table 16-1.
- This will have the immediate effect of raising
Ee. - The increase in Ee shifts the AA curve to the
right again. - The equilibrium moves from point 3 to point 2 in
Fig 17-14. - Both E and Y increase more for a permanent
increase in MS than for a temporary increase in
MS.
45Fig. 17-14 Short-Run Effects of a Permanent
Increase in the Money Supply
46Table 16-1 Effects of Money Market and Output
Market Changes on the Long-Run Nominal
Dollar/Euro Exchange Rate, E/
47Permanent ? in Ms Overshooting?
AA1 is the initial AA curveAA2 is AA1 plus
effect of Ee? caused by permanent ? in Ms.AA3 is
AA2 plus effect of Ms/P? caused by permanent ? in
Ms.In the long run, Ms/P returns to original
level. So, the economy goes from a green dot to a
black dot in the short run, and to the higher of
the two green dots in the long run.
E
E
E
DD2
DD2
DD2
DD1
DD1
DD1
AA3
AA3
AA3
AA2
AA2
AA2
AA1
AA1
AA1
Y
Yf
Y
Yf
Y
Yf
Neither over nor under!
Overshooting
Undershooting
48Macroeconomic Policies and the Current Account
- By recalling the effects of various policies on
the real dollar/euro exchange rate (q EP/P)
and on disposable income (Yd Y - T), we can
figure out their effects on the current account
(CA).