最新巴罗宏观经济学：现代观点第16章PPT课件.ppt

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1、巴罗宏观经济学：现代观点第巴罗宏观经济学：现代观点第16章章The New Keynesian Model2 Extensions:lImperfect competition:the typical producer actively sets its price.lSticky prices:nominal goods prices that do not react rapidly to changed circumstances.menu costJournal price2Macroeconomics Chapter 16 Extra:Price Setting Under Impe

2、rfect Competition9Macroeconomics Chapter 16 Extra:Price Setting Under Imperfect CompetitionUnder imperfect competition,each firm can set P(j)above its nominal marginal cost.The ratio of P(j)to the nominal marginal cost is called the markup ratiofirm j s markup ratio =P(j)/MC(j)10Macroeconomics Chapt

3、er 16 Extra:Price Setting Under Imperfect CompetitionP(j)=(markup ratio)MC(j)The production function for firm j looks like the function we have used before:Y(j)=F(j)K(j),L(j)MPL(j)=Y(j)/L(j)11Macroeconomics Chapter 16 MC(j)=w/MPL(j)P(j)=(markup ratio)w/MPL(j)Extra:Price Setting Under Imperfect Compe

4、tition12Macroeconomics Chapter 16 The New Keynesian ModelShort-Run Responses to a Monetary ShocklImagine M doubles.In this setting,each nominal price,P(j),doubles when M doubles.The average price,P,doublesThe economy-wide nominal wage rate,w,also doubles as before.These changes leave unchanged the r

5、eal variables in the economy.The real variables now include not only the economy-wide real wage rate,w/P,but also the ratio of each firms price to the average price,P(j)/P.13Macroeconomics Chapter 16 The New Keynesian ModelShort-Run Responses to a Monetary Shock with Sticky PriceslThe average price,

6、P,would then also be fixed.lIf P is constant and M doubles,each household would have twice as much real money,M/P,as before.lHowever,nothing has changed to motivate households to hold more money in real terms.Each household would therefore try to spend its excess money,partly by buying the goods pro

7、duced by the various firms.lEach firm j would then experience an increase in the quantity demanded of its goods,Yd(j).14Macroeconomics Chapter 16 The New Keynesian ModellTo raise its production,Y(j),firm j has to increase its quantity of labor input,L(j).lTherefore,the quantity of labor demanded,Ld(

8、j),rises by the amount:Ld(j)=Y(j)/MPL(j)lWith a fixed price P(j),an increase in the nominal quantity of money,M,leads to an expansion of labor demand by each firm j.15Macroeconomics Chapter 16 The New Keynesian Model16Macroeconomics Chapter 16 The New Keynesian ModellAn increase in the nominal quant

9、ity of money from M to M raises the market-clearing labor input from L to(L)on the horizontal axis.lWith the increase in labor input,each firm produces more goods.Thus,real GDP increases.lWe therefore have that a monetary expansion is non-neutral.An increase in the nominal quantity of money raises r

10、eal GDP.Moreover,labor input,L,moves in a procyclical mannerit rises along with Y.17Macroeconomics Chapter 16 The New Keynesian ModelNew Keynesian PredictionslThe predictions from the new Keynesian model are similar to those from the price-misperceptions model.lThat model also gave the result that a

11、 monetary expansion raised real GDP,Y,and labor input,L.18Macroeconomics Chapter 16 The New Keynesian ModelDifference between the two models:w/Plthe price-misperceptions model,an expansion of L had to be accompanied by a fall in w/P in order to induce employers to use more labor input.that model pre

12、dictedcounterfactuallythat w/P would be countercyclical.lthat a monetary expansion increases the market-clearing real wage rate from(w/P)to(w/P)on the vertical axis.Therefore,the model generates a procyclical pattern for w/P.19Macroeconomics Chapter 16 The New Keynesian ModelNew Keynesian Prediction

13、slKeynesian model predicts,counterfactually,that Y/L would be countercyclical.lKeynesian economists have used the idea of labor hoarding to improve the models predictions about labor productivity.20Macroeconomics Chapter 16 The New Keynesian ModelPrice Adjustment in the Long RunlIn the long run,the

14、prices adjust,and tend to undo the real effects from a change in M.lP(j)=(markup ratio)w/MPL(j)lThe real effect of a monetary shock in the new Keynesian model is a short-run result that applies only as long as prices fail to adjust to their equilibrium levels.21Macroeconomics Chapter 16 The New Keyn

15、esian ModellData do reveal stickiness of some prices.lHowever,a tentative conclusion from empirical research with these new data is that price stickiness is insufficient to explain a major part of economic fluctuations.22Macroeconomics Chapter 16 The New Keynesian ModelComparing Predictions for Econ

16、omic FluctuationslThe new Keynesian model correctly predicts a procyclical pattern for the real wage rate,w/P,and a countercyclical pattern for the price level,P.lThe new Keynesian model errs by predicting a countercyclical pattern for Y/L,although the idea of labor hoarding might fix this problem.2

17、3Macroeconomics Chapter 16 The New Keynesian Model24Macroeconomics Chapter 16 The New Keynesian ModelShocks to Aggregate DemandlEach firm j experienced an increase in the demand for its goods,Yd(j),while its price,P(j),was held fixed.The same results apply if Yd(j)rises for each firm j for reasons h

18、aving nothing to do with money.The essential ingredient is an increase in the aggregate demand for goods.25Macroeconomics Chapter 16 The New Keynesian ModelShocks to Aggregate DemandlOne way for aggregate demand to rise is for households to shift exogenously away from current saving and toward curre

19、nt consumption,C.lAnother possibility is that the government could boost the aggregate demand for goods by increasing its real purchases,G.26Macroeconomics Chapter 16 The New Keynesian ModelShocks to Aggregate DemandlAn increase in the aggregate demand for goods may end up increasing real GDP,Y,by e

20、ven more than the initial expansion of demand.lThat is,there may be a multiplier in the modelthe rise in Y may be a multiple greater than one of the rise in demand.27Macroeconomics Chapter 16 Money and Nominal Interest RatesIn practice,central bankssuch as the Federal Reservetend to express monetary

21、 policy as targets for short-term nominal interest rates,rather than monetary aggregates.In the United States,especially since the early 1980s,the Fed focuses on the Federal Funds ratethe overnight nominal interest rate in the Federal Funds market,which comprises financial institutions,such as comme

22、rcial banks.28Macroeconomics Chapter 16 Money and Nominal Interest RatesThe Federal Reserves Federal Open Market Committee(FOMC)meets eight or more times a year.At each meeting,the FOMC adopts a target for the Federal Funds rate.29Macroeconomics Chapter 16 Money and Nominal Interest RatesThe central

23、 idea is that,in the short run with sticky prices,open-market operations affect nominal interest ratesthe Federal Funds rate in the United States and the nominal interest rate,i,in our model.30Macroeconomics Chapter 16 Money and Nominal Interest RatesM=P L(Y,i)In the new Keynesian model,P is fixed i

24、n the short run.Thus,if M increases,equilibrium requires some combination of higher Y or lower i to raise the nominal quantity of money demanded by the same amount.For a given Y,a higher M has to match up with a lower i 31Macroeconomics Chapter 16 Money and Nominal Interest RatesIn our previous anal

25、ysis,we thought of an expansionary monetary shock as an increase in the nominal quantity of money,M.Now we can think of an expansionary monetary action as a decrease in the nominal interest rate,i.32Macroeconomics Chapter 16 Money and Nominal Interest RatesIt nearly impossible for the Fed to designa

26、te in advance the precise time path for the monetary base or some other monetary aggregate needed to achieve a desired part for i.Central banks have rejected proposals,originally put forward by Milton Friedman,to have a constant-growth-rate rule for a designated monetary aggregate.33Macroeconomics C

27、hapter 16 Money and Nominal Interest RatesBecause of the shortcomings in rules based on monetary aggregates,the Fed and other central banks tend to frame their policies in terms of targeted adjustments in nominal interest rates,iAn important point is that the Fed does not have to know the exact spec

28、ification for L(Y,i).The Fed just keeps raising M until it sees the nominal interest rate that it wants.34Macroeconomics Chapter 16 Money and Nominal Interest Rates35Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage RatesSticky nominal wage rates that is,a failure of nominal wage rate

29、s to react rapidly to changed circumstances.Perfect competition.In this setting,the single nominal price,P,applies to all goods.36Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage RatesKeynes focused on a case in which w was higher than its market-clearing level.This assumption will i

30、mply that the real wage rate,w/P,will be above its market-clearing value.37Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage Rates38Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage RatesThe excess of the quantity of labor supplied(at the given real wage rate,w/P)over L

31、 is called involuntary unemployment.39Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage RatesSuppose,now,that a monetary expansion raises the price level,P.If the nominal wage rate,w,does not change,the rise in P lowers the real wage rate,w/P.This fall in w/P raises the quantity of la

32、bor demanded,Ld,and,thereby,increases labor input on the horizontal axis from L to L.40Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage Rates41Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage RatesWith sticky nominal wage rates,a monetary expansion raises labor input,

33、L.The increase in L leads through the production function to an expansion of real GDP,Y.42Macroeconomics Chapter 16 The Keynesian ModelSticky Nominal Wage RatesThe Keynesian model is similar to the new Keynesian model in predicting that M and L would be procyclical.However,unlike the new Keynesian m

34、odel,the Keynesian model predicts that w/P would be countercyclical.We have stressed that w/P typically moves in a procyclical manner.Therefore,the Keynesian model has difficulty explaining the observed cyclical behavior of w/P.43Macroeconomics Chapter 16 Long-Term Contracts and Sticky Nominal Wage

35、RatesFor many workers,nominal wage rates are set for one or more years by the terms of agreements made with employers.These agreements are sometimes formal contracts between firms and labor unions.More commonly,firms and workers have implicit contracts that specify in advance the nominal wage rate o

36、ver some period,often a fiscal or calendar year.44Macroeconomics Chapter 16 Long-Term Contracts and Sticky Nominal Wage RatesSuppose that an employer and employee agree on a fixed nominal wage rate,w,for the next year.A natural choice is to set w equal to the best estimate of the average market-clea

37、ring nominal wage rate,w,that will prevail over the year.Although the chosen w may be a rational expectation of w,unanticipated events lead to mistakes.45Macroeconomics Chapter 16 Long-Term Contracts and Sticky Nominal Wage RatesWhen the contract expires,the employer and employee agree on a new nomi

38、nal wage rate,w,for the next year.This new w takes account of events during the current year,including the inflation rate,.Thus,if expectations are rational,mistakes in the setting of w for this yeardue perhaps to underestimation of inflationtend not to be repeated the next year.46Macroeconomics Cha

39、pter 16 Long-Term Contracts and Sticky Nominal Wage RatesAt any point in time,the economy has an array of existing labor contracts,each of which specifies a nominal wage rate,w,that likely deviates somewhat from the market clearing value,w.Some of these agreements have w greater than w,and others ha

40、ve w less than w.47Macroeconomics Chapter 16 Long-Term Contracts and Sticky Nominal Wage RatesImportant empirical works:lAhmed(1987):index contractslOlivei et al.(2007):shocks in different seasons have different effect.48Macroeconomics Chapter 16 Long-Term Contracts and Sticky Nominal Wage RatesAn i

41、mportant lesson from the contracting approach:lStickiness of the nominal wage rate,w,need not lead to the unemployment and underproduction that appears in the Keynesian model.49Macroeconomics Chapter 16 Extra:IS-LM modelrI,SS(y)I(r)50Macroeconomics Chapter 16 Extra:IS-LM modelrY51Macroeconomics Chap

42、ter 16 Extra:IS-LM modeli=rM/PAssume now that P is fixed52Macroeconomics Chapter 16 Extra:IS-LM modelrYMonetary policy:M increases53Macroeconomics Chapter 16 Extra:IS-LM modelrYEquilibrium:Monetary policy:M increases 54Macroeconomics Chapter 16 Extra:AD-AS modelrYAggregate Demand:M fixed and P decre

43、ases LM curve moves downR decreases andY increases55Macroeconomics Chapter 16 Extra:AD-AS modelPYAggregate Demand:P decreases andY increases56Macroeconomics Chapter 16 Extra:AD-AS modelPYAggregate Supply:Long run:Y is fixedShort run:P is fixed57Macroeconomics Chapter 16 Extra:AD-AS modelrYAggregate Supply:Long run:Y is fixedShort run:P is fixed58Macroeconomics Chapter 16 Extra:AD-AS modelPYAD-AS:59Macroeconomics Chapter 16 结束语结束语谢谢大家聆听！谢谢大家聆听！60