宏观经济学课件：10 Philips curve

1、 主要内容： 菲利普斯曲线的定义 菲利普斯曲线的推导 长期菲利普斯曲线 短期菲利普斯曲线的移动 When money supply increases, the AD curve shifts right. How does this affect the price level and unemployment rate? 总需求曲线向右移动时， 物价水平，产量和失业率将怎样变化？ Shifts in the AD curveABAD1ASAD2PriceLevelOutput 总需求曲线向右移动时，经济将达到平衡点B点 在B点时，物价水平上升，产量增加，而失业率将下降。 由图形显示，物价水

2、平变化，与失业率的变化是反方向的。失业和通货膨胀 Origins of the Phillips Curve In 1958, an economist named A. W. Phillips wrote an article discussing the negative correlation between inflation rates and unemployment rates in the United Kingdom.The Phillips CurveInflation rateUnemploymentratePhillips CurvePhillips Curve The

3、 belief was that low unemployment is related to high aggregate demand, and high aggregate demand puts upward pressure on wages and prices. High unemployment is related to low aggregate demand, and low aggregate demand pulls price levels down. 低失业时候，由于总需求高，推高物价和工资水平，则通货膨胀上升。 高失业时，总需求减少，物价水平下降。 Philli

4、ps Curve: a curve that shows the short-run tradeoff between inflation and unemployment. Samuelson and Solow believed that the Phillips curve offered policymakers a menu of possible economic outcomes. Policymakers could use monetary and fiscal policy to choose any point on the curve. 政府利用货币财政政策的选择，可以

5、使经济在该曲线上变动。菲利普斯曲线的推导 Aggregate Demand, Aggregate Supply, and the Phillips Curve The Phillips curve shows the combinations of inflation and unemployment that arise in the short run due to shifts in the aggregate demand curve.总需求曲线的移动Shifts in the AD curve Given that monetary and fiscal policy can bot

6、h shift the aggregate-demand curve, these types of policies can move the economy along the Phillips curve.政府通过调整货币政策，改变经济当中的失业率和通货膨胀水平。 a.Increases in the money supply, moves the economy to a point on the Phillips curve with lower unemployment and higher inflation.增加货币供给, 总需求上升，降低失业率. 经济达到B点位置。 b. D

7、ecreases in the money supply, decreases in government spending, move the economy to a point on the Phillips curve with higher unemployment and lower inflation. 减少货币供给, 降低通货膨胀,提高失业率.总需求下降。Shifts in the AD curveABAD1ASAD2PriceLevelOutputThe Phillips CurveInflation rateUnemploymentratePhillips CurveBAS

8、hifts in the Phillips Curve: The Role of Expectations The Long-Run Phillips Curve In 1968, economist Milton Friedman argued that monetary policy is only able to choose a combination of unemployment and inflation for a short period of time. 弗里德曼提出货币供给的变化只在短期影响失业和通货膨胀。长期菲利普斯曲线 In the long run, we woul

9、d not expect there to be a relationship between unemployment and inflation. The Phillips curve is vertical. The vertical long-run Phillips curve is one expression of the classical ideal of monetary neutrality.古典理论的货币中性,使长期菲力普斯曲线是垂线.The Long Run Phillips CurveLong Run Phillips CurveInflation rate The

10、 long-run aggregate-supply curve occurs at the economys natural rate of output; thus, the long-run Phillips curve occurs at the natural rate of unemployment. 长期菲利普斯曲线上失业率等于自然失业率。Shift of the Long Run Phillips CurveChange in ProductivityShift on the Long RunPhillips CurveChange in the Natural rate of

11、 unemployment 如果长期总供给曲线向右移动， 自然失业率降低，那么长期菲利普斯曲线会向左移动。 自然失业率和劳动生产效率的变化会使长期的非力普斯曲线产生移动。Expectations and the Short-Run Phillips Curve The expected rate of inflation is one variable which determines the position of the short-run aggregate-supply curve. 预期通货膨胀决定短期菲利普斯曲线。 Unemployment= natural rate of une

12、mployment a*(actual inflation-expected inflation) Higher actual inflation is associated with lower unemployment. 当实际通货膨胀高于预期通货膨胀时，失业率低于自然失业率。Shifts in the Phillips Curve In the short-run, peoples expectations are somewhat fixed. -When the Fed increases the money supply, aggregate demand increases al

13、ong the upward sloping short-run aggregate-supply curve. Output grows (unemployment falls) and the price level rises (inflation increases). From A to point B. 政府增加货币供给，使产量上升物价水平上涨，失业减少。经济从A点向上移动到B 点。 -Eventually, people will begin expecting a higher rate of inflation.预期物价上涨。Shifts in the Phillips Cu

14、rve -When expected inflation rises, the Phillips curve shifts upward. 当预期通货膨胀 上升,菲力普斯曲线向上移动.从B点到C点移动。 -The economy ends up at a point with higher inflation and with the same level of unemployment. From B to point C. 最后经济移动到C点，通货膨胀上升，失业率不变。Shifts in the Phillips Curve Inflation rateACBUnemployment ra

15、te 预期通货膨胀上升，短期菲利普斯曲线向右移动。 预期通货膨胀减少，短期菲利普斯曲线向左移动。货币政策对菲利普斯曲线的影响 当货币供给上升时，总需求提高，经济会沿着一条菲利普斯曲线向左移动。通货膨胀上升，失业率降低。经济从A点向上移动到B 点。 当货币供给下降时， 经济会沿着菲利普斯曲线向右边移动，使失业上升，通货膨胀降低。 当公众提高了预期通胀，菲利普斯曲线将向右移动。经济达到C 点位置。选择题1 1.According to the Phillips curve, policymakers would reduce inflation but raise unemployment if

16、they a. decreased the money supply. b. increased government expenditures. c.decreased taxes. d. None of the above is correct. 2. If policymakers decrease aggregate demand, then in the long run a. prices will be lower and unemployment will be higher. b. prices will be lower and unemployment will be u

17、nchanged. c.prices and unemployment will be unchanged. d. None of the above is correct. 3.Friedman and Phelps argued a.that in the long run, monetary growth did not influence those factors that determine the economys unemployment rate. b.that the Phillips curve could be exploited in the long run by

18、using monetary, but not fiscal policy. c.that the short-run Phillips curve was very steep, but not vertical. d.that there was neither a short-run nor long-run tradeoff between inflation and unemployment. 4. If the Federal Reserve increases the rate at which it increases the money supply, then unempl

19、oyment is lower a. in the long run and the short run. b. in the long run but not the short run. c.in the short run but not the long run. d. in neither the short run nor the long run. 5. How would a decrease in the natural rate of unemployment affect the long-run Phillips curve? a. It would shift the

20、 long-run Phillips curve right. b. It would shift the long-run Phillips curve left. c.There would be an upward movement along a given long-run Phillips curve. d. There would be a downward movement along a given long-run Philips curve. 6. If expected inflation increases, which of the following shifts

21、 right? a. both the short-run and the long-run Phillips curves b. the short-run but not the long-run Phillips curve c.the long-run but not the short-run Phillips curve d. neither the long-run nor the short-run Phillips curveThe Natural Experiment The Phillips Curve in the 1960s Beginning in the late

22、 1960s, the government followed policies that increased aggregate demand. a.Increased government spending because of the Vietnam War. 越南战争使政府赤字增加。 b. Increases in the money supply to try to keep interest rates down.货币供应上升 As a result of these policies, the inflation rate remained fairly high. Howeve

23、r, even though inflation remained high, unemployment did not remain low. 但政策并没有使失业减少。 Policymakers had learned that Friedman were right: there is no tradeoff between inflation and unemployment in the long run. 所以，现实证明在长期中并不存在失业和通货膨胀间的取舍关系。Shifts in the Phillips Curve Friedman had suggested in 1968 t

24、hat changes in expected inflation shift the short-run Phillips curve . 预期物价引起短期曲线移动。Shifts in the Phillips Curve: The Role of Supply Shocks Supply Shock:供给冲击 an event that directly alters firms costs and prices, shifting the economys aggregate-supply curve and thus the Phillips curve. In 1974, OPEC

25、increased the price of oil sharply. 石油危机This increased the cost of producing many goods and services and therefore resulted in higher prices.供给冲击We could represent this supply shock as a shift in the short-run aggregate supply curve to the left.供给冲击使短期总供给曲线左移.The decrease in equilibrium output and t

26、he increase in the price level left the economy with stagflation.经济产生滞胀.菲力普斯曲线右移 Given this turn of events, policymakers are left with a less favorable short-run tradeoff between unemployment and inflation. The Philips curve shifts to the right. 预期物价上升使菲力普斯曲线右移。经济中的失业和通货膨胀的短期取舍变坏了。AS curve shifts to

27、 the left, StagflationPrice levelOutputAS1The Phillips curve shifts to the rightPC2PC1Inflation rate The Phillips curve shifts to the rightShort run AS curve Shift leftPhillips curveShift rightExpected inflation increasesAdverseSupply shock不利的冲击 Is the adverse shift in the Phillips curve temporary o

28、r permanent? 菲力普斯曲线右移是暂时还是持久的？ If people expect the rise in inflation as a temporary event, expected inflation does not change, and the Phillips curve will soon move to its former position.当预期通货膨胀不变时，菲力普斯曲线回到原位。判断题练习 1。According to the natural rate hypothesis, the unemployment rate should equal 0 pe

29、rcent in the long run. F 2。The long-run Phillips curve is a upward-sloping line at the natural rate of unemployment. F 3。A decrease in the growth rate of the money supply eventually causes the short-run Phillips curve to shift right. F 4。An adverse supply shock shifts the short-run Phillips curve ri

30、ght and the short-run aggregate-supply curve left. T 5。An increase in inflation expectations shifts the short-run Phillips curve right and has no effect on the long-run Phillips curve. T 6。A policy change that reduces the natural rate of unemployment shifts both the long-run aggregate-supply curve a

31、nd the long-run Phillips curve left. F 7。In the long run people come to expect whatever inflation rate the Fed chooses to produce, so unemployment returns to its natural rate. T 8。In the Friedman-Phelps analysis, when inflation is less than expected, the unemployment rate is less than the natural ra

32、te. F 9。Fiscal policy cannot be used to move the economy along the short-run Phillips curve. F 10。If the Fed were to increase the money supply, inflation would increase and unemployment would decrease in the short run. T 11。 The proliferation of Internet usage serves as an example of a favorable sup

33、ply shock. T选择题2 1. According to Friedman and Phelpss analysis of the Phillips curve, a.the unemployment rate will be below its natural rate whenever inflation is negative. b.the unemployment rate will be below its natural rate whenever inflation is positive. c.the unemployment rate will be below it

34、s natural rate only if inflation is less than expected. d.the unemployment rate will be below its natural rate only if inflation is greater than expected. 2. A policy intended to reduce unemployment by taking advantage of a tradeoff between inflation and unemployment leads to a.both higher inflation

35、 and higher unemployment in the long run. b.higher inflation and no change in unemployment in the long run. c.the same inflation rate and lower unemployment in the long run. d.higher inflation and lower unemployment in the long run3. In the long run, a decrease in the money supply growth rate a. shi

36、fts the short-run Phillips curve left so inflation returns to its original rate. b. shifts the short-run Phillips curve left so unemployment returns to its natural rate. c.Both A and B are correct. d. None of the above is correct. 4. Which of the following is correct if there is a favorable supply s

37、hock? a.the short-run aggregate supply curve and the short-run Phillips curve both shift right. b.the short-run aggregate supply curve and the short-run Phillips curve both shift left. c.the short-run aggregate supply curve shifts right and the short-run Phillips curve shifts left. d.the short-run a

38、ggregate supply curve shifts left and the short-run Phillips curve shifts right.The Costs of Reducing Inflation 治理通货膨胀的成本。 To reduce the inflation rate, the Fed has to pursue contractionary monetary policy. 政府采取紧缩的货币政策，治理通货膨胀。 When money supply is growing slower, it reduces the aggregate demand and

39、leads to a fall in employment. 紧缩的货币政策，将导致经济衰退，使产量下降，通货膨胀降低，失业率增加。The Costs of Reducing Inflation Sacrifice Ratio: 牺牲比率 the number of percentage points of annual output lost in the process of reducing inflation by 1 percentage point. A typical estimate of the sacrifice ratio is 5. This implies that

40、for each percentage point inflation is decreased, output falls by 5 percen牺牲率t.一般是5，物价水平每减少1%，产量下降5%。 sacrifice ratio= % Fall in output/ % Fall in inflation Sacrifice ratio= (-30%)/(-6%)=5 In order to reduce inflation by 6%, the annual GDP would be falling by 30%. 假设物价下降6%，那么产量将减少30%。The Possibility

41、 of Costless Disinflation Rational Expectations: 理性预期 the theory according to which people optimally use all the information they have, including information about government policies, when forecasting the future. This implies that the short-run Phillips curve would shift quickly without any extende

42、d period of high unemployment. 在理性预期下，短期曲线会快速移动，而不会产生长期高失业。 降低通货膨胀的政策可以采取2个方法: 1. 紧缩的货币政策, 但会引起产量下降,经济进入严重衰退.失业增加。 A点到B点。 2. 利用理性预期理论. 紧缩的货币政策, 同时调整预期通货膨胀, 使预期通货膨胀降低，菲利普斯曲线向左移动。会引起产量轻微减少, 经济发展基本稳定. A点到C点。Zero Sacrifice ratio If the government made a commitment to a policy of low inflation, people wo

43、uld be rational enough to lower the expectation of inflation quickly. 当公众降低通货膨胀预期后，短期曲线将向左移动。失业率和物价水平同时下降。 The short run Phillips curve would shift to the left.The Volcker disinflation Inflation Unemployment rate 1979 11.2% 6% 1981 10.4% 7.5% 1983 6.2% 1983 3.2% 9.5% 1987 3.6% 6.1% The fall inflatio

44、n is attributed to the anti-inflation monetary policy by the Fed. Inflation rate fell from 11.2% to 3.6% but unemployment rate was unchanged.The Phillips Curve shifts to the leftInflationPC1PC2The Greenspan Era In 1986, OPECs agreement with its members broke down and oil prices fell. The result of t

45、his favorable supply shock was a drop in both inflation and unemployment. Since then, inflation gradually dropped, approaching zero by the end of the decade. This likely implies that the short-run Phillips curve has drifted leftward, giving the United States a more favorable tradeoff between inflati

46、on and unemployment. What factors should cause the long run Phillips curve shift to the left?Shift of the Long Run Phillips CurveChange in ProductivityShift on the Long RunPhillips CurveChange in the Natural rate of unemployment Causes of this movement in the short-run Phillips curve include:u-reduc

47、tions in expected inflation, 预期通货膨胀降低 -lower commodity prices, 有利的供给冲击 -changes in the stability of the labor force, -technological advancements.科学技术发展Problems in Book 2. A rise in the natural rate of unemployment shifts the long-run Phillips curve to the right. The economy is initially on LRPC1 and

48、 SRPC1 at an inflation rate of 3 percent, which is also the expected rate of inflation. The increase in the natural rate of unemployment shifts the long-run Phillips curve to LRPC2 and the short-run Phillips curve to SRPC2, with the expected rate of inflation remaining equal to 3 percent. B. A decli

49、ne in the price of imported oil shifts the short-run Phillips curve down, as shown in Figure 33-10, from SRPC1 to SRPC2. For any given unemployment rate, the inflation rate is lower, since oil is such a significant aspect of production costs in the economy. C. A rise in government spending represent

50、s an increase in aggregate demand, so it moves the economy along the short-run Phillips curve,. The economy moves from point A to point B, with a decline in the unemployment rate and an increase in the inflation rate. 3. 1 The decline in consumer spending reduces aggregate demand, shifting the aggre

51、gate-demand curve to the left from AD1 to AD2. The economy initially remains on the short-run aggregate-supply curve SRAS1, so the new equilibrium occurs at point B. The movement of the aggregate-demand curve along the short-run aggregate-supply curve leads to a movement along short-run Phillips cur

52、ve SRPC1, from point A to point B. 3.2 As expected inflation rises over time, the short-run aggregate-supply curve shifts down from AS1 to AS2, and the short-run Phillips curve shifts down from SRPC1 to SRPC2. In both diagrams, the economy eventually gets to point C, which is back on the long-run ag

53、gregate-supply curve and long-run Phillips curve. After the recession is over, the economy faces a better set of inflation-unemployment combinations. 4.a.Figure 14 shows the economy in long-run equilibrium at point A, which is on both the long-run and short-run Phillips curves. b. A wave of business pessimism reduces aggrega