微观经济学34InfluenceofMonetaryandFiscalPolicyonAD

1、34 the influence of monetary and fiscal policy on aggregate demandaggregate 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.aggregate demand when d

2、esired spending changes, aggregate demand shifts, causing short-run fluctuations in output and employment. monetary and fiscal policy are sometimes used to offset those shifts and stabilize the economy.34.1 how monetary policy influences aggregate demand34.1 how monetary policy influences aggregate

3、demand the aggregate demand curve slopes downward for three reasons: the wealth effect the interest-rate effect the exchange-rate effect34.1 how monetary policy influences aggregate demand for the chinese economy, the most important reason for the downward slope of the aggregate-demand curve is the

4、wealth effect. for the u.s. economy, the most important reason for the downward slope of the aggregate-demand curve is the interest-rate effect.34.1.1 the theory of liquidity preference keynes developed the theory of liquidity preference in order to explain what factors determine the economys intere

5、st rate. according to the theory, the interest rate adjusts to balance the supply and demand for money.34.1.1 the theory of liquidity preference money supply the money supply is controlled by the fed through: open-market operations changing the reserve requirements changing the discount rate because

6、 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.34.1.1 the theory of liquidity preference money demand money demand is determined by several factors. according to the theory of liquidity pr

7、eference, one of the most important factors is the interest rate. 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. the opportunity cost of holding money is the interest that could be earned on interest-earning

8、assets. an increase in the interest rate raises the opportunity cost of holding money. as a result, the quantity of money demanded is reduced.34.1.1 the theory of liquidity preference equilibrium in the money market according to the theory of liquidity preference: the interest rate adjusts to balanc

9、e the supply and demand for money. there is one interest rate, called the equilibrium interest rate, at which the quantity of money demanded equals the quantity of money supplied.34.1.1 the theory of liquidity preference equilibrium in the money market assume the following about the economy: the pri

10、ce 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 1 equilibrium in the money marketquantity ofmoneyinterestrate0moneydemandquantity fixed

11、by the fedmoneysupplyr2m2dmdr1equilibriuminterestrate34.1.2 the downward slope of the aggregate demand curve the price level is one determinant of the quantity of money demanded. a higher price level increases the quantity of money demanded for any given interest rate. higher money demand leads to a

12、 higher interest rate. the quantity of goods and services demanded falls.34.1.2 the downward slope of the aggregate demand curve the end result of this analysis is a negative relationship between the price level and the quantity of goods and services demanded.figure 2 the money market and the slope

13、of the aggregate-demand curvequantityof moneyquantity fixedby the fed0interestratemoney demand at price level p2, md2 money demand atprice level p , md moneysupply(a) the money market(b) the aggregate-demand curve3. . . . whichincreasesthe equilibriuminterestrate . . . 2. . . . increases thedemand f

14、or money . . . quantityof output0pricelevelaggregatedemandp2y2yp4. . . . which in turn reduces the quantityof goods and services demanded.1. anincreasein thepricelevel . . . rr234.1.3 changes in the money supply the fed can shift the aggregate demand curve when it changes monetary policy. an increas

15、e in the money supply shifts the money supply curve to the right. without a change in the money demand curve, the interest rate falls. falling interest rates increase the quantity of goods and services demanded.figure 3 a monetary injectionms2moneysupply, msaggregatedemand, adyypmoney demand at pric

16、e level pad2quantityof money0interestraterr2(a) the money market(b) the aggregate-demand curvequantityof output0pricelevel3. . . . which increases the quantity of goods and services demanded at a given price level.2. . . . theequilibriuminterest ratefalls . . . 1. when the fedincreases themoney supp

17、ly . . . 34.1.3 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

18、 rate and reduces the quantity of goods and services demanded at any given price level, shifting aggregate-demand to the left.34.1.4 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. changes in monet

19、ary policy can be viewed either in terms of a changing target for the interest rate or in terms of a change in the money supply. a target for the federal funds rate affects the money market equilibrium, which influences aggregate demand.34.2 how fiscal policy influences aggregate demand34.2 how fisc

20、al policy influences aggregate demand fiscal policy refers to the governments 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.34.2.1 c

21、hanges in government purchases when policymakers change the money supply or taxes, the effect on aggregate demand is indirectthrough the spending decisions of firms or households. when the government alters its own purchases of goods or services, it shifts the aggregate-demand curve directly.34.2.1

22、changes in government purchases there are two macroeconomic effects from the change in government purchases: the multiplier effect the crowding-out effect34.2.2 the multiplier effect government purchases are said to have a multiplier effect on aggregate demand. each dollar spent by the government ca

23、n raise the aggregate demand for goods and services by more than a dollar.34.2.2 the multiplier effect 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 multiplie

24、r effectquantity ofoutputpricelevel0aggregate demand, ad1$20 billionad2ad31. an increase in government purchasesof $20 billion initially increases aggregatedemand by $20 billion . . . 2. . . . but the multipliereffect can amplify theshift in aggregatedemand.34.2.3 a formula for the spending multipli

25、er the formula for the multiplier is:multiplier = 1/(1 - mpc)= 1/ mps 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.34.2.3 a formula for the spending multiplier if the mpc is 3/4, then t

26、he 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.110,10.11,1)1 ()2() 1 ()2(1) 1 (1)1 ()459),(3,(132132132132kznzzzziiiiiiyiypnnnnnnnn，因此，所以当由于式，得：式减以令：因此该级数是收敛的，假设小于消费倾向穷几何级

27、数，由于边际括号中各项代表一个无资增量，则：分别代表收入增量和投和以宏观部分版西方经济学第高鸿业乘数公式的证明.1111,11.1,1) 1 (.1111.1) 1 (.,)()462),(0101010000000mpckgygggyyytgiytgiygmpcgyktgiytyygitygicypggd变动，则：，只有政府购买支出式中，若其他条件不变在一、政府购买支出乘数其中三部门中的总支出：宏观高鸿业西方经济学三部门经济中各种乘数.11,11.1,1) 1 (.1) 1 (.,)()462),(0101100000000mpcmpcktytttyyytgiytgiyttgiytyygit

28、ygicyptaxd变动，则：，只有政府税收式中，若其他条件不变在二、政府税收乘数其中三部门中的总支出：宏观高鸿业西方经济学三部门经济中各种乘数bdgdykxgimabybmxgibymmycmxgicyg11)(11.,000所以则为边际进口倾向为边际消费倾向为常数其中宏观经济模型，得：解答：考虑开放经济的？政府购买乘数的表达式推导开放经济条件下的34.2.5 the crowding-out effect fiscal policy may not affect the economy as strongly as predicted by the multiplier. an incre

29、ase in government purchases causes the interest rate to rise. a higher interest rate reduces investment spending.34.2.5 the crowding-out effect this reduction in demand that results when a fiscal expansion raises the interest rate is called the crowding-out effect. the crowding-out effect tends to d

30、ampen (vt. make sth. less strong, restrain) the effects of fiscal policy on aggregate demand.figure 5 the crowding-out effectquantityof moneyquantity fixedby the fed0interestratermoney demand, mdmoneysupply(a) the money market3. . . . whichincreasestheequilibriuminterestrate . . . 2. . . . the incre

31、ase inspending increasesmoney demand . . . md2quantityof output0pricelevelaggregate demand, ad1 (b) the shift in aggregate demand4. . . . which in turnpartly offsets theinitial increase inaggregate demand.ad2ad31. when an increase in government purchases increases aggregatedemand . . . r2$20 billion

32、34.2.5 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.34.2.6 changes in taxes when the governm

33、ent 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 aggregate-demand curve to the right.34.2.6 changes in taxes the size of the shift in aggr

34、egate demand resulting from a tax change is affected by the multiplier and crowding-out effects. it is also determined by the households perceptions (n. way of seeing, or understanding sth.看法,理解) about the permanency of the tax change.34.3 using policy to stabilize the economy34.3 using policy to st

35、abilize the economy economic stabilization has been an explicit goal of u.s. policy since the employment act of 1946.34.3.1 the case for active stabilization policy the employment act has two implications: the government should avoid being the cause of economic fluctuations. the government should re

36、spond to changes in the private economy in order to stabilize aggregate demand.34.3.2 the case against active stabilization policy some economists argue that monetary and fiscal policy destabilizes the economy. monetary and fiscal policy affect the economy with a substantial lag. they suggest the ec

37、onomy should be left to deal with the short-run fluctuations on its own.34.3.3 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 stabiliz

38、ers include the tax system and some forms of government spending.34.3.3 automatic stabilizers the most important automatic stabilizer is the tax system. when the economy goes into a recession, the amount of taxes collected by the government falls automatically because almost all taxes are closely ti

39、ed to economic activity. the personal income tax depends on householdsincomes, the payroll tax depends on workersearnings, and the corporate income tax depends on firmsprofits. because incomes, earnings, and profits all fall in a recession, the governmentss tax revenue falls as well. this automatic

40、tax cut stimulates aggregate demand and, thereby, reduces the magnitude of economic fluctuations.34.3.3 automatic stabilizers government spending also acts as an automatic stabilizer. in particular, when the economy goes into a recession and workers are laid off, more people apply for unemployment i

41、nsurance benefits, welfare benefits, and other forms of income support. this automatic increase in government spending stimulates aggregate demand at exactly the time when aggregate demand is insufficient to maintain full employment. (indeed, when the unemployment insurance system was first enacted

42、in the 1930s, economists who advocated this policy did so in part because of its power as an automatic stabilizer.)34.3.3 automatic stabilizers the automatic stabilizer in the u.s. economy are not sufficiently strong to prevent recessions completely. nonetheless, without these automatic stabilizers,

43、 output and employment would probably be more volatile than they are.summary keynes proposed the theory of liquidity preference to explain determinants of the interest rate. according to this theory, the interest rate adjusts to balance the supply and demand for money.summary an increase in the pric

44、e level raises money demand and increases the interest rate. a higher interest rate reduces investment and, thereby, the quantity of goods and services demanded. the downward-sloping aggregate-demand curve expresses this negative relationship between the price-level and the quantity demanded.summary

45、 policymakers can influence aggregate demand with monetary policy. an increase in the money supply will ultimately lead to the aggregate-demand curve shifting to the right. a decrease in the money supply will ultimately lead to the aggregate-demand curve shifting to the left.summary policymakers can

46、 influence aggregate demand with fiscal policy. an increase in government purchases or a cut in taxes shifts the aggregate-demand curve to the right. a decrease in government purchases or an increase in taxes shifts the aggregate-demand curve to the left.summary when the government alters spending o

47、r taxes, the resulting shift in aggregate demand can be larger or smaller than the fiscal change. 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.summary because monetary

48、 and fiscal policy can influence aggregate demand, the government sometimes uses these policy instruments in an attempt to stabilize the economy. economists disagree about how active the government should be in this effort. advocates say that if the government does not respond the result will be und

49、esirable fluctuations. critics argue that attempts at stabilization often turn out destabilizing.mankiw,ch34, question for review 1.what is the theory of liquidity preference? how does it help explain the downward slope of the aggregate-demand curve? 2. use the theory of liquidity preference to expl

50、ain how a decrease in the money supply affects the aggregate-demand curve. 3. (mankiw-chapter34 )解释在封闭经济中，为什么政府税收乘数小于政府支出乘数？ 4. (mankiw-chapter34)解释为什么封闭经济中的支出乘数大于开放经济的支出乘数？复习题1. 什么是流动偏好理论？ 这种理论如何有助于解释总需求曲线的向右下方倾斜？2. 用流动偏好理论解释货币供给减少如何影响总需求曲线。3. 政府支出30亿美元购买警车。解释为什么总需求的增加会大于或小于30亿美元。4. 假设对消费者信心衡量指标的调查

51、表明，悲观主义情绪蔓延全国。如果决策者无所作为，总需求会发生什么变动？ 如果美联储想稳定总需求，它应该怎么做？ 如果美联储无所作为，国会为了稳定总需求应该做什么 ？5. 举出一个起到自动稳定器作用的政府政策的例子。解释为什么这种政策有这种效应。(mankiw-chapter 34-p778) 1.explain how each of the following developments would affect the supply of money, the demand for money, and the interest rate. illustrate your answers w

52、ith diagrams. a. a wave of optimism boosts business investment.b. the central bank reduces reserve requirements. c. an increase in oil prices shifts the short-run aggregate-supply curve upward. d. households decide to hold more money to use for holiday shopping.msmdmdr1r2利利率率货币量货币量(a) a wave of opti

53、mism boosts business investment, thereby increase demand for money and interest rate will rise.msmdr1r2利利率率货币量货币量(b)the central bank reduces reserve requirements signifies that the supply of money will shift rightward with constant the demand for money, the interest rate will decline.msmsmdmdr1r2利利率

54、率货币量货币量(c) pqasasadp1p2(mankiw chapter 34 -p778.)2. suppose banks install automatic teller machines on every block and, by making cash readily available, reduce the amount of money people want on hold.a. assume the fed does not change the money supply. according to the theory of liquidity preference

55、, what happens to the interest rate? what happens to aggregate demand?b. if the fed wants to stabilize aggregate demand, how should it respond?(mankiw chapter 34 -p778.)3.consider two policies-a tax cut that will last for only one year, and a tax cut that is expected to be permanent. which policy wi

56、ll stimulate greater spending by consumers? which policy will have the greater impact on aggregate demand? explain.(mankiw chapter 34 -p778.)4. the interest rate in the united states fell sharply during 1991. many observers believed this decline showed that monetary policy was quite expantionary dur

57、ing the year. could this conclusion be incorrect? (hint:the united states hit the trough of a recession in 1991.) (mankiw chapter 34 -p778.)5. in the early 1980s, new legislation allowed banks to pay interest on checking deposits, which they could not do previously.a. if we define money to include c

58、hecking deposits, what effect did this legislation have on money demand? explain.b. if the federal reserve had maintained a constant money supply in the face of this change, what would have happened to the interest rate? what would have happen to aggregate demand and aggregate output?c. if the feder

59、al reserve had maintained a constant market interest rate (the interest rate on nonmonetary assets) in the face of this change, what change in the money supply would have been necessary? what would have happened to aggregate demand and aggregate output?(mankiw, chapter34.-p779.)6.this chapter explai

60、ns that expansionary monetary policy reduces the interest rate and thus stimulates demand for consumption and investment goods. explain how such policy also stimulates the demand for net exports.(mankiw, chapter34.-p779.)7. suppose economists observe that an increase in government spending of $10 bi