经济学原理课件：Chapter 35 通货膨胀与失业之间的短期权衡

1、135通货膨胀与失业之间的短期权衡通货膨胀与失业之间的短期权衡The Short-Run Tradeoff between Inflation and Unemployment2失业与通货膨胀失业与通货膨胀Unemployment and Inflationl两个密切受到注视的经济状况指标是通货膨两个密切受到注视的经济状况指标是通货膨胀和失业。胀和失业。 Two closely watched indicators of economic performance are inflation and unemployment.l将通货膨胀率和失业率相加得到将通货膨胀率和失业率相加得到痛苦指数痛苦

2、指数，它是经济它是经济“健康健康”的一个衡量指标。的一个衡量指标。 The misery index, one measure of the “health” of the economy, adds together the inflation rate and unemployment rate.3失业与通货膨胀失业与通货膨胀Unemployment and Inflationl通胀与失业的关系这一话题吸引了过去通胀与失业的关系这一话题吸引了过去半个世纪最重要的一些经济学家的注意半个世纪最重要的一些经济学家的注意力。力。l关于通胀与失业的思想史不可避免地和关于通胀与失业的思想史不可避免地和

3、美国经济的历史相联系。美国经济的历史相联系。l这两种历史将说明为什么通货膨胀与失这两种历史将说明为什么通货膨胀与失业之间的权衡取舍在短期中成立而在长业之间的权衡取舍在短期中成立而在长期中不成立。期中不成立。4失业失业与通货膨胀：与通货膨胀：长期长期Unemployment and Inflation: The Long-runl自然失业率依赖于劳动力市场的各种特征。自然失业率依赖于劳动力市场的各种特征。The natural rate of unemployment depends on various features of the labor market.l例如，最低工资法、工会的市场权

4、力、效率例如，最低工资法、工会的市场权力、效率工资的作用、寻找工作的有效性。工资的作用、寻找工作的有效性。 Examples include minimum-wage laws, the market power of unions, the role of efficiency wages, and the effectiveness of job search.5失业与失业与通货膨胀通货膨胀：长期长期Unemployment and Inflation: The Long-runl通货膨胀率主要依赖于货币数量的增长，它通货膨胀率主要依赖于货币数量的增长，它是由美联储控制的。是由美联储控制的

5、。 The inflation rate depends primarily on growth in the quantity of money, controlled by the Fed.l因此，在长期中，因此，在长期中，通货膨胀和失业基本是互通货膨胀和失业基本是互不相关的问题不相关的问题。 In the long run, therefore, inflation and unemployment are largely unrelated problems.6失业与通货膨胀：失业与通货膨胀：短期短期Unemployment and Inflation: The Short-runl社

6、会面临着失业与通货膨胀之间的短期权衡。社会面临着失业与通货膨胀之间的短期权衡。 Society faces a short-run tradeoff between unemployment and inflation.l如果政策制定者扩张总需求，他们能够降低失业，但必如果政策制定者扩张总需求，他们能够降低失业，但必须以更高的通货膨胀为代价。须以更高的通货膨胀为代价。 If policymakers expand aggregate demand, they can lower unemployment, but only at the cost of higher inflation.l如果

7、他们紧缩总需求，他们能够降低通货膨胀，但必须如果他们紧缩总需求，他们能够降低通货膨胀，但必须以暂时更高的失业率为代价。以暂时更高的失业率为代价。 If they contract aggregate demand, they can lower inflation, but at the cost of temporarily higher unemployment.7菲利普斯曲线菲利普斯曲线The Phillips Curvel1958年，年，AW菲利普斯将英国自菲利普斯将英国自1861至至1957年历年的年历年的通货膨胀率与失业率绘制成图。通货膨胀率与失业率绘制成图。 In 1958, A

8、.W. Phillips drew a diagram plotting the rate of inflation against the rate of unemployment in the United Kingdom for each year from 1861 to 1957.l他发现通货膨胀率与失业率之间有明显的负相关关系他发现通货膨胀率与失业率之间有明显的负相关关系：当失业率低时，通货膨胀率高，而当失业率高时，：当失业率低时，通货膨胀率高，而当失业率高时，通货膨胀低，甚至经常是负的。通货膨胀低，甚至经常是负的。 He found clear evidence of a neg

9、ative relation between inflation and unemployment: When unemployment was low, inflation was high, and when unemployment was high, inflation was low, often even negative.8菲利普斯曲线菲利普斯曲线The Phillips Curve9菲利普斯曲线菲利普斯曲线The Phillips Curvel两年之后，保罗两年之后，保罗萨缪尔森与罗伯特萨缪尔森与罗伯特索洛用美索洛用美国国1900至至1960年的数据重复了菲利普斯的工作年的数据

10、重复了菲利普斯的工作Two years later, Paul Samuelson and Robert Solow replicated Phillips exercise for the United States, using data from 1900 to 1960.l除了失业率非常高的三十年代，看起来在美国除了失业率非常高的三十年代，看起来在美国也存在通胀率与失业率之间的负相关关系。也存在通胀率与失业率之间的负相关关系。Apart from the period of very high unemployment during the 1930s, there appeared

11、to be a negative relation between inflation and unemployment in the United States also.10菲利普斯曲线菲利普斯曲线The Phillips Curve11菲利普斯曲线菲利普斯曲线The Phillips Curve菲利普斯曲线菲利普斯曲线表示了通货膨胀与失表示了通货膨胀与失业之间的（业之间的（短期短期）权衡取舍。）权衡取舍。 The Phillips curve illustrates the (short-run) trade-off between inflation and unemployment.

12、12菲利普斯曲线菲利普斯曲线The Phillips Curve.失业率（百分比）失业率（百分比）Unemployment Rate (percent)0通货膨胀率通货膨胀率（每年百分比）（每年百分比）Inflation Rate (percent per year)4B6A72菲利普斯曲线菲利普斯曲线Phillips curve13菲利普斯曲线菲利普斯曲线The Phillips Curve菲利普斯曲线看起来向政策制定者提菲利普斯曲线看起来向政策制定者提供了一系列通货膨胀与失业可能的组供了一系列通货膨胀与失业可能的组合。合。 The Phillips curve seems to offer

13、 policymakers a menu of possible inflation and unemployment outcomes.14总需求、总供给与菲利普斯曲线总需求、总供给与菲利普斯曲线Aggregate Demand, Aggregate Supply, and the Phillips Curvel菲利普斯曲线表示失业率与通货膨胀率的短期菲利普斯曲线表示失业率与通货膨胀率的短期组合，它源于总需求曲线的移动使经济沿着短组合，它源于总需求曲线的移动使经济沿着短期总供给曲线变动。期总供给曲线变动。 The Phillips curve shows the short-run comb

14、inations of unemployment and inflation that arise as shifts in the aggregate demand curve move the economy along the short-run aggregate supply curve.15总需求、总供给与菲利普斯曲线总需求、总供给与菲利普斯曲线Aggregate Demand, Aggregate Supply, and the Phillips Curvel对于物品与服务的总需求越大，经济的产出越对于物品与服务的总需求越大，经济的产出越大，整体价格水平越高。大，整体价格水平越高

15、。 The greater the aggregate demand for goods and services, the greater is the economys output, and the higher is the overall price level.l更高的产出水平导致更低的失业水平。更高的产出水平导致更低的失业水平。 A higher level of output results in a lower level of unemployment.16菲利普斯曲线Phillips curve0 (b) 菲利普斯曲线菲利普斯曲线The Phillips CurveInf

16、lation Rate (percent per year)Unemployment Rate (percent)0(a) ADAS模型模型The Model of AD and ASPrice Level低ADLow AD高ADHigh ADB46(output is 8,000)A72(output is 7,500)A7,500102(unemployment is 7%)B8,000106(unemployment is 4%)短期ASShort-run AS菲利普斯曲线如何与总供求模型相联系菲利普斯曲线如何与总供求模型相联系 How the Phillips Curve is Rel

17、ated to the Model of Aggregate Demand and Aggregate Supply.Quantity of Output17长期菲利普斯曲线长期菲利普斯曲线The Long-Run Phillips Curvel在二十世纪六十年代后期，弗里德曼和费在二十世纪六十年代后期，弗里德曼和费尔普斯断定，通货膨胀率与失业率在长期尔普斯断定，通货膨胀率与失业率在长期不相关。不相关。 In the late 1960s, Friedman and Phelps concluded that inflation and unemployment are unrelated i

18、n the long run.l因此，长期的菲利普斯曲线垂直于因此，长期的菲利普斯曲线垂直于自然失自然失业率业率处。处。 As a result, the long-run Phillips curve is vertical at the natural rate of unemployment.l货币政策在短期有效，但在长期无效。货币政策在短期有效，但在长期无效。 Monetary policy could be effective in the short run but not in the long run.18长期菲利普斯曲线长期菲利普斯曲线The Long-Run Phillip

19、s Curve.Unemployment Rate0自然失业率自然失业率Natural rate of unemploymentInflation Rate长期菲利普斯曲线长期菲利普斯曲线Long-run Phillips curveB高通胀高通胀High inflation 1. 当美联储提高当美联储提高货币供给的增长货币供给的增长率，通货膨胀率率，通货膨胀率上升上升 When the Fed increases the growth rate of the money supply, the rate of inflation increases 2. 但是失业率在但是失业率在长期会保持在

20、其自长期会保持在其自然率上然率上 but unemployment remains at its natural ratein the long run.A低通胀低通胀Low inflation 自然失业率自然失业率Natural rate of unemployment长期菲利普斯曲线长期菲利普斯曲线Long-run Phillips curve0(b) 菲利普斯曲线菲利普斯曲线The Phillips CurveInflation RateA自然产出率自然产出率Natural rate of output0P1总需求总需求Aggregate demand, AD1 长期总供给长期总供给 L

21、ong-run aggregate supply(a) 总供求模型总供求模型The Model of Aggregate Demand and Aggregate Supply Price Level4. 但产出和失业率停留在其自然率上但产出和失业率停留在其自然率上 but leaves output and unemployment at their natural rates.P22. 提升了价提升了价格水平格水平 raises the price levelQuantity of OutputUnemploy-ment Rate 1. 货币供给的上升增加货币供给的上升增加了总需求了总需求

22、 An increase in the money supply increases aggregate demandAD2B3. 提高了通货提高了通货膨胀率膨胀率 and increases the inflation rate菲利普斯曲线是如何与总供求模型相联系的菲利普斯曲线是如何与总供求模型相联系的 How the Phillips Curve is Related to the Model of Aggregate Demand and Aggregate Supply20预期与短期菲利普斯曲线预期与短期菲利普斯曲线Expectations and the Short-Run Phil

23、lips Curvel问题：古典宏观经济理论预言（长问题：古典宏观经济理论预言（长期）垂直菲利普斯曲线，而证据显期）垂直菲利普斯曲线，而证据显示（短期内）失业与通胀之间存在示（短期内）失业与通胀之间存在权衡取舍，如何协调？权衡取舍，如何协调？ Question: How can classical macroeconomic theories predicting a vertical long run Phillips curve be reconciled with the evidence that, in the short run, there is a tradeoff betwe

24、en unemployment and inflation?21预期与短期菲利普斯曲线预期与短期菲利普斯曲线Expectations and the Short-Run Phillips Curvel预期通货膨胀率预期通货膨胀率衡量了人们预计整体价格水平衡量了人们预计整体价格水平将变化多少。将变化多少。 Expected inflation measures how much people expect the overall price level to change.l预期通货膨胀率的引入使得短期与长期菲利普预期通货膨胀率的引入使得短期与长期菲利普斯曲线可以协调。斯曲线可以协调。 The

25、introduction of expected inflation reconciles the long-run Philips curve with the short-run Philips curve.22预期与短期菲利普斯曲线预期与短期菲利普斯曲线Expectations and the Short-Run Phillips Curve失业率失业率Unemployment Rate=自然失业率自然失业率 Natural rate of unemployment实际通胀率实际通胀率 预期通胀率预期通胀率 Actual Expected inflation inflation-()a-

26、这一等式将失业率与自然失业率、实际通胀率与这一等式将失业率与自然失业率、实际通胀率与预期通胀率联系在一起预期通胀率联系在一起 This equation relates the unemployment rate to the natural rate of unemployment, actual inflation, and expected inflation.u=un-a( - e)23预期与短期菲利普斯曲线预期与短期菲利普斯曲线Expectations and the Short-Run Phillips Curvel在短期中，预期通货膨胀率是既定的，在短期中，预期通货膨胀率是既定的

27、，较高的实际通货膨胀与较低的失业相联较高的实际通货膨胀与较低的失业相联系。系。 失业率失业率Unemployment Rate=自然失业率自然失业率 Natural rate of unemployment实际通胀率实际通胀率 预期通胀率预期通胀率 Actual Expected inflation inflation-()a-24预期与短期菲利普斯曲线预期与短期菲利普斯曲线Expectations and the Short-Run Phillips Curvel在长期中，预期通货膨胀率与实际通货在长期中，预期通货膨胀率与实际通货膨胀的变动相一致，失业率等于其自然膨胀的变动相一致，失业率等于

28、其自然率。率。失业率失业率Unemployment Rate=自然失业率自然失业率 Natural rate of unemployment实际通胀率实际通胀率 预期通胀率预期通胀率 Actual Expected inflation inflation-()a-25预期与短期菲利普斯曲线预期与短期菲利普斯曲线Expectations and the Short-Run Phillips Curvel政策制定者面对的仅是暂时的通货膨胀与失业政策制定者面对的仅是暂时的通货膨胀与失业的权衡取舍。的权衡取舍。 Policy makers face only a temporary trade-off

29、 between inflation and unemployment.l在长期，总需求更为迅速的扩张将导致更高的在长期，总需求更为迅速的扩张将导致更高的通货膨胀，而不能减少失业。通货膨胀，而不能减少失业。 In the long run, expanding aggregate demand more rapidly will yield higher inflation without reduction in unemployment.26预期与短期菲利普斯曲线预期与短期菲利普斯曲线Expectations and the Short-Run Phillips Curvel假设决策者试图

30、通过用货币政策或者财假设决策者试图通过用货币政策或者财政政策扩大总需求。政政策扩大总需求。扩张性政策如何移动经济扩张性政策如何移动经济How Expansionary Policy Moves the Economy.Unemployment Rate0自然失业率自然失业率 Natural rate of unemploymentInflation Rate长期菲利普斯曲线长期菲利普斯曲线Long-run Phillips curveAC具有高预期通胀的短期菲利普斯曲线具有高预期通胀的短期菲利普斯曲线Short-run Phillips curve with high expected inf

31、lation具有低预期通胀的短期菲利普斯曲线具有低预期通胀的短期菲利普斯曲线Short-run Phillips curve with low expected inflationB1. 扩张性的政策使经扩张性的政策使经济沿着短期菲利普斯济沿着短期菲利普斯曲线向上移动曲线向上移动Expansionary policy moves the economy up along the short-run Phillips curve.2. 但在长期，预期通胀率上升，但在长期，预期通胀率上升，短期菲利普斯曲线向右移动短期菲利普斯曲线向右移动 but in the long-run, expected

32、inflation rises, and the short-run Phillips curve shifts to the right.28自然率假说自然率假说The Natural-Rate Hypothesisl无论通胀率如何，失业最终会回到其自然率无论通胀率如何，失业最终会回到其自然率上，这一观点被称为上，这一观点被称为自然率假说自然率假说。 The view that unemployment eventually returns to its natural rate, regardless of the rate of inflation, is called the natu

33、ral-rate hypothesis.l历史观察支持了自然率假说。历史观察支持了自然率假说。 Historical observations support the natural-rate hypothesis.29自然率假说的自然实验自然率假说的自然实验 The Natural Experiment for the Natural Rate Hypothesisl稳定的菲利普斯曲线的概念在七十年代早期破稳定的菲利普斯曲线的概念在七十年代早期破产了。产了。 The concept of a stable Phillips curve broke down in the early 70s.

34、l在七十和八十年代内，经济同时经历了高通胀在七十和八十年代内，经济同时经历了高通胀与高失业。与高失业。 During the 70s and 80s, the economy experienced high inflation and high unemployment simultaneously.30二十世纪六十年代的菲利普斯曲线二十世纪六十年代的菲利普斯曲线The Phillips Curve in the 1960s.Unemployment Rate (percent)Inflation Rate(percent per year)0123456789102468101968196

35、619611962196319671965 196431菲利普斯曲线的破产菲利普斯曲线的破产 The Breakdown of the Phillips Curve.Unemployment Rate (percent)Inflation Rate(percent per year)01234567891024681019731971196919701968196619611962196319671965 1964197232菲利普斯曲线的移动：供给冲击的作用菲利普斯曲线的移动：供给冲击的作用Shifts in the Phillips Curve: The Role of Supply Sh

36、ocksl历史事件表明，短期菲利普斯曲线会因为预期历史事件表明，短期菲利普斯曲线会因为预期的改变而移动。的改变而移动。 Historical events have shown that the short-run Phillips curve can shift due to changes in expectations. l短期菲利普斯曲线也会因为对总供给的冲击而短期菲利普斯曲线也会因为对总供给的冲击而移动。移动。 The short-run Phillips curve also shifts because of shocks to aggregate supply. 33菲利普斯曲

37、线的移动：供给冲击的作用菲利普斯曲线的移动：供给冲击的作用Shifts in the Phillips Curve: The Role of Supply Shocksl总供给的重大不利变动会恶化失业与通胀的短总供给的重大不利变动会恶化失业与通胀的短期权衡。期权衡。 Major adverse changes in aggregate supply can worsen the short-run tradeoff between unemployment and inflation.l不利的供给冲击带给政策制定者更为不利的通不利的供给冲击带给政策制定者更为不利的通胀与失业的权衡。胀与失业的权

38、衡。 An adverse supply shock gives policymakers a less favorable tradeoff between inflation and unemployment.34菲利普斯曲线的移动：供给冲击的作用菲利普斯曲线的移动：供给冲击的作用Shifts in the Phillips Curve: The Role of Supply Shocksl供给冲击供给冲击是直接影响企业的生产成本因而影是直接影响企业的生产成本因而影响其价格制定的事件。响其价格制定的事件。 A supply shock is an event that directly a

39、ffects firms costs of production and thus the prices they charge. l它会移动经济的总供给曲线它会移动经济的总供给曲线 It shifts the economys aggregate supply curve. l并最终移动其菲利普斯曲线并最终移动其菲利普斯曲线 and as a result, the Phillips curve.35对总供给的不利冲击对总供给的不利冲击 An Adverse Shock to Aggregate Supply.Quantity of Output0Price LevelP1Aggregate

40、 demand(a) The Model of Aggregate Demand and Aggregate SupplyUnemploy-ment Rate0(b) The Phillips CurveAInflation RatePhillips curve, PC1 Aggregate supply, AS1AY1=YnP23. 提高了价格水平提高了价格水平and raises the price levelB2. 降低了产出降低了产出 lowers outputY2AS21. 总供给的不利移总供给的不利移动动An adverse shift in aggregate supplyY3=

41、YnunBPC2 4. 带给政策制定者更为不带给政策制定者更为不利的失业与通胀的权衡利的失业与通胀的权衡giving policymakers a less favorable tradeoff between unemployment and inflation.unCC36Inflation Rate(percent per year)UnemploymentRate (percent)0123456789102468101972197519811976197819791980197319741977二十世纪七十年代的供给冲击二十世纪七十年代的供给冲击 The Supply Shocks

42、of the 1970s.37菲利普斯曲线的移动：供给冲击的作用菲利普斯曲线的移动：供给冲击的作用Shifts in the Phillips Curve: The Role of Supply Shocksl在二十世纪七十年代，当欧佩克削减石油产出提在二十世纪七十年代，当欧佩克削减石油产出提高其价格时，政策制定者面对两个选择。高其价格时，政策制定者面对两个选择。 In the 1970s, policymakers faced two choices when OPEC cut output and raised worldwide prices of petroleum.l通过扩张总需求、

43、加速通胀来打一场失业攻坚战。通过扩张总需求、加速通胀来打一场失业攻坚战。 Fight the unemployment battle by expanding aggregate demand and accelerate inflation.l通过紧缩总需求和承受甚至更高的失业率来对付通胀通过紧缩总需求和承受甚至更高的失业率来对付通胀Fight inflation by contracting aggregate demand and endure even higher unemployment.38降低通货膨胀的代价降低通货膨胀的代价The Cost of Reducing Inflat

44、ionl独立的中央银行应当保持通货价值并防止独立的中央银行应当保持通货价值并防止通货膨胀通货膨胀l那么，降低通货膨胀的短期代价是什么？那么，降低通货膨胀的短期代价是什么？39降低通货膨胀的代价降低通货膨胀的代价The Cost of Reducing Inflationl为了降低通胀，美联储不得不推行为了降低通胀，美联储不得不推行紧缩性紧缩性的货币政策。的货币政策。 To reduce inflation, the Fed has to pursue contractionary monetary policy. l当美联储减慢货币增长率时，它就紧缩了总需求。当美联储减慢货币增长率时，它就紧缩

45、了总需求。 When the Fed slows the rate of money growth, it contracts aggregate demand.l这就减少了企业生产的物品与服务的数量。这就减少了企业生产的物品与服务的数量。 This reduces the quantity of goods and services that firms produce.l这就导致了失业的上升。这就导致了失业的上升。 This leads to a rise in unemployment.AShort-run Phillips curvewith high expectedInflatio

46、n高预期通胀短期菲利普斯曲线高预期通胀短期菲利普斯曲线1.紧缩性政策使经济沿着短期菲紧缩性政策使经济沿着短期菲利普斯曲线向下移动利普斯曲线向下移动 Contractionary policy moves the economy down along the short-run Phillips curve.UnemploymentRate0自然失业率自然失业率 Natural rate ofunemploymentInflationRate长期菲利普斯曲长期菲利普斯曲线线Long-run Phillips curveCBShort-run Phillips curvewith low expe

47、ctedInflation低预期通胀短期菲利普斯曲线低预期通胀短期菲利普斯曲线2. . 但是在长期，预期通胀率下降，短期菲利普斯曲线向左但是在长期，预期通胀率下降，短期菲利普斯曲线向左移动移动 but in the long run, expected inflation falls and the short-run Phillips curve shifts to the left.短期和长期中的反通胀货币政策短期和长期中的反通胀货币政策 Disinflationary Monetary Policy in the Short Run and the Long Run.41降低通货膨胀的代

48、价降低通货膨胀的代价The Cost of Reducing Inflationl为了降低通胀，经济必须经受一段时间的高失为了降低通胀，经济必须经受一段时间的高失业与低产出。业与低产出。 To reduce inflation, an economy must endure a period of high unemployment and low output.l当美联储抗击通胀时，经济沿短期菲利普斯曲线向当美联储抗击通胀时，经济沿短期菲利普斯曲线向下移动。下移动。 When the Fed combats inflation, the economy moves down the shor

49、t-run Phillips curve.l经济经历了更低的通胀，但付出的代价则是更高的经济经历了更低的通胀，但付出的代价则是更高的失业。失业。 The economy experiences lower inflation but at the cost of higher unemployment.42降低通货膨胀的代价降低通货膨胀的代价The Cost of Reducing Inflationl牺牲率牺牲率是在降低通胀的过程中，每降低一个百分是在降低通胀的过程中，每降低一个百分点的通胀率，所损失的年度产出的百分比数字。点的通胀率，所损失的年度产出的百分比数字。The sacrifice

50、 ratio is the number of percentage points of annual output that is lost in the process of reducing inflation by one percentage point.l牺牲率的一个估计数字是牺牲率的一个估计数字是5 An estimate of the sacrifice ratio is five.l为了将通胀率从为了将通胀率从1979-81年间的年间的10降到降到4，就要求，就要求牺牲年度产出的大约牺牲年度产出的大约30。 To reduce inflation from about 10%

51、 in 1979-1981 to 4% would have required an estimated sacrifice of 30% of annual output!43降低通货膨胀的代价降低通货膨胀的代价The Cost of Reducing Inflation 但是理性预期学说却认为，降低通货膨胀但是理性预期学说却认为，降低通货膨胀的代价并没有牺牲率估计的那么大。的代价并没有牺牲率估计的那么大。44理性预期理性预期Rational Expectations理性预期理性预期理论认为，人们在预测未来时，理论认为，人们在预测未来时，会最佳地利用他们拥有的所有信息，包括会最佳地利用他们拥

52、有的所有信息，包括对政府政策的信息。对政府政策的信息。 The theory of rational expectations suggests that people optimally use all the information they have, including information about government policies, when forecasting the future.提出者：罗伯特提出者：罗伯特卢卡斯（卢卡斯（Robert Lucas）、托马斯、托马斯萨金特（萨金特（Thomas Sargent）、）、罗伯特罗伯特巴罗（巴罗（Robert Barro

53、）45理性预期理性预期Rational Expectationsl理性预期理论认为理性预期理论认为 The theory of rational expectations suggests thatl企业和工人可以预期企业和工人可以预期未来未来的通货膨胀率。的通货膨胀率。 Firms and workers have come to expect rates of inflation in the future.l当经济政策改变时，人们会相应地调整对通胀率的预期。当经济政策改变时，人们会相应地调整对通胀率的预期。 When economic policies change, people ad

54、just their expectations of inflation accordingly.l结果是，牺牲率可以比估计的小很多。结果是，牺牲率可以比估计的小很多。 As a result, the sacrifice-ratio could be much smaller than estimated.l如果政府做出了降低通胀的如果政府做出了降低通胀的可信可信承诺，人们的理性就足以立即降承诺，人们的理性就足以立即降低通胀预期。低通胀预期。 If the government made a credible commitment to a policy of low inflation,

55、people would be rational enough to lower their expectations of inflation immediately.46沃克尔的反通货膨胀沃克尔的反通货膨胀The Volcker Disinflationl当保罗当保罗沃克尔在二十世纪七十年代担任沃克尔在二十世纪七十年代担任美联储主席的时候，人们普遍认为，通美联储主席的时候，人们普遍认为，通胀是这个国家首要的问题之一。胀是这个国家首要的问题之一。 When Paul Volcker was Fed chairman in the 1970s, inflation was widely vie

56、wed as one of the nations foremost problems.l沃克尔在降低通胀方面是成功的（从沃克尔在降低通胀方面是成功的（从10降到了降到了4），但是付出了高失业的代），但是付出了高失业的代价（在价（在1983年为年为10）。）。 Volcker succeeded in reducing inflation (from 10% to 4%), but at the cost of high unemployment (about 10% in 1983).47UnemploymentRate (percent)Inflation Rate(percent per

57、 year)012345678910246810197919801983198119821984198619871985ABC沃克尔的反通货膨胀沃克尔的反通货膨胀 The Volcker Disinflation.48格林斯潘时代格林斯潘时代The Greenspan Eral艾伦艾伦格林斯潘甫任美联储主席，即获有利供给冲击。格林斯潘甫任美联储主席，即获有利供给冲击。 Alan Greenspans term as Fed chairman began with a favorable supply shock. l在在1986年，欧佩克成员放弃了他们的限产协定。年，欧佩克成员放弃了他们的限产协定。 In 1986, OPEC