巴罗宏观经济学：现代观点第16章.ppt

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1、Macroeconomics Chapter 16,1,Money and Business Cycles II:Sticky Prices and Nominal Wage Rates,C h a p t e r 1 6,Macroeconomics Chapter 16,2,The New Keynesian Model,2 Extensions:Imperfect competition:the typical producer actively sets its price.Sticky prices:nominal goods prices that do not react rap

2、idly to changed circumstances.menu costJournal price,Macroeconomics Chapter 16,3,The New Keynesian Model,Price Setting Under Imperfect CompetitionLet P(j)be the price charged for a good by firm j.the quantity demanded of firm j s goods is q(j),Macroeconomics Chapter 16,4,The New Keynesian Model,Pric

3、e Setting Under Imperfect CompetitionTypically,q(j)depends on relative price P(j)/P andthe income of consumers,Macroeconomics Chapter 16,5,Extra:Price Setting Under Imperfect Competition,Pure MonopolyA single seller,who chooses price and quantity to maximize profits.Entry into the market is complete

4、ly blocked by technological or legal barriers.,The monopolists profit-maximization problem:,Macroeconomics Chapter 16,6,Extra:Price Setting Under Imperfect Competition,FOC:,is the elasticity of market demand at output.,Macroeconomics Chapter 16,7,Extra:Price Setting Under Imperfect Competition,Courn

5、ot Oligopoly:,The choice variable is the quantity.All firms choose simultaneously.,J identical firms produce a homogeneous good.,Their cost function is same:,The inverse market demand is:,Macroeconomics Chapter 16,8,Extra:Price Setting Under Imperfect Competition,The profit function of firm j is:,FO

6、C:,Macroeconomics Chapter 16,9,Extra:Price Setting Under Imperfect Competition,Macroeconomics Chapter 16,10,Extra:Price Setting Under Imperfect Competition,Under 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 ma

7、rkup ratiofirm j s markup ratio=P(j)/MC(j),Macroeconomics Chapter 16,11,Extra:Price Setting Under Imperfect Competition,P(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),Macroeconomics Chapter 16,12,MC(j)=w/MPL(j

8、)P(j)=(markup ratio)w/MPL(j),Extra:Price Setting Under Imperfect Competition,Macroeconomics Chapter 16,13,The New Keynesian Model,Short-Run Responses to a Monetary ShockImagine M doubles.In this setting,each nominal price,P(j),doubles when M doubles.The average price,P,doublesThe economy-wide nomina

9、l wage rate,w,also doubles as before.These changes leave unchanged the real 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.,Macroeconomics Chapter 16,14,The New Keynesian Model,Sh

10、ort-Run Responses to a Monetary Shock with Sticky PricesThe average price,P,would then also be fixed.If P is constant and M doubles,each household would have twice as much real money,M/P,as before.However,nothing has changed to motivate households to hold more money in real terms.Each household woul

11、d therefore try to spend its excess money,partly by buying the goods produced by the various firms.Each firm j would then experience an increase in the quantity demanded of its goods,Yd(j).,Macroeconomics Chapter 16,15,The New Keynesian Model,To raise its production,Y(j),firm j has to increase its q

12、uantity of labor input,L(j).Therefore,the quantity of labor demanded,Ld(j),rises by the amount:Ld(j)=Y(j)/MPL(j)With 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.,Macroeconomics Chapter 16,16,The New Keynesian Model,Macroecono

13、mics Chapter 16,17,The New Keynesian Model,An increase in the nominal quantity of money from M to M raises the market-clearing labor input from L to(L)on the horizontal axis.With the increase in labor input,each firm produces more goods.Thus,real GDP increases.We therefore have that a monetary expan

14、sion is non-neutral.An increase in the nominal quantity of money raises real GDP.Moreover,labor input,L,moves in a procyclical mannerit rises along with Y.,Macroeconomics Chapter 16,18,The New Keynesian Model,New Keynesian PredictionsThe predictions from the new Keynesian model are similar to those

15、from the price-misperceptions model.That model also gave the result that a monetary expansion raised real GDP,Y,and labor input,L.,Macroeconomics Chapter 16,19,The New Keynesian Model,Difference between the two models:w/Pthe price-misperceptions model,an expansion of L had to be accompanied by a fal

16、l in w/P in order to induce employers to use more labor input.that model predictedcounterfactuallythat w/P would be countercyclical.that 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.

17、,Macroeconomics Chapter 16,20,The New Keynesian Model,New Keynesian PredictionsKeynesian model predicts,counterfactually,that Y/L would be countercyclical.Keynesian economists have used the idea of labor hoarding to improve the models predictions about labor productivity.,Macroeconomics Chapter 16,2

18、1,The New Keynesian Model,Price Adjustment in the Long RunIn the long run,the prices adjust,and tend to undo the real effects from a change in M.P(j)=(markup ratio)w/MPL(j)The 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

19、 adjust to their equilibrium levels.,Macroeconomics Chapter 16,22,The New Keynesian Model,Data do reveal stickiness of some prices.However,a tentative conclusion from empirical research with these new data is that price stickiness is insufficient to explain a major part of economic fluctuations.,Mac

20、roeconomics Chapter 16,23,The New Keynesian Model,Comparing Predictions for Economic FluctuationsThe new Keynesian model correctly predicts a procyclical pattern for the real wage rate,w/P,and a countercyclical pattern for the price level,P.The new Keynesian model errs by predicting a countercyclica

21、l pattern for Y/L,although the idea of labor hoarding might fix this problem.,Macroeconomics Chapter 16,24,The New Keynesian Model,Macroeconomics Chapter 16,25,The New Keynesian Model,Shocks to Aggregate DemandEach firm j experienced an increase in the demand for its goods,Yd(j),while its price,P(j)

22、,was held fixed.The same results apply if Yd(j)rises for each firm j for reasons having nothing to do with money.The essential ingredient is an increase in the aggregate demand for goods.,Macroeconomics Chapter 16,26,The New Keynesian Model,Shocks to Aggregate DemandOne way for aggregate demand to r

23、ise is for households to shift exogenously away from current saving and toward current consumption,C.Another possibility is that the government could boost the aggregate demand for goods by increasing its real purchases,G.,Macroeconomics Chapter 16,27,The New Keynesian Model,Shocks to Aggregate Dema

24、ndAn increase in the aggregate demand for goods may end up increasing real GDP,Y,by even more than the initial expansion of demand.That is,there may be a multiplier in the modelthe rise in Y may be a multiple greater than one of the rise in demand.,Macroeconomics Chapter 16,28,Money and Nominal Inte

25、rest Rates,In practice,central bankssuch as the Federal Reservetend to express monetary 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 interes

26、t rate in the Federal Funds market,which comprises financial institutions,such as commercial banks.,Macroeconomics Chapter 16,29,Money and Nominal Interest Rates,The Federal Reserves Federal Open Market Committee(FOMC)meets eight or more times a year.At each meeting,the FOMC adopts a target for the

27、Federal Funds rate.,Macroeconomics Chapter 16,30,Money and Nominal Interest Rates,The central 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.,Macroeconomics

28、Chapter 16,31,Money and Nominal Interest Rates,M=P L(Y,i)In the new Keynesian model,P is fixed in 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

29、 with a lower i,Macroeconomics Chapter 16,32,Money and Nominal Interest Rates,In our previous analysis,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.,Macr

30、oeconomics Chapter 16,33,Money and Nominal Interest Rates,It nearly impossible for the Fed to designate 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 Milto

31、n Friedman,to have a constant-growth-rate rule for a designated monetary aggregate.,Macroeconomics Chapter 16,34,Money and Nominal Interest Rates,Because of the shortcomings in rules based on monetary aggregates,the Fed and other central banks tend to frame their policies in terms of targeted adjust

32、ments in nominal interest rates,iAn important point is that the Fed does not have to know the exact specification for L(Y,i).The Fed just keeps raising M until it sees the nominal interest rate that it wants.,Macroeconomics Chapter 16,35,Money and Nominal Interest Rates,Macroeconomics Chapter 16,36,

33、The Keynesian ModelSticky Nominal Wage Rates,Sticky nominal wage rates that is,a failure of nominal wage rates to react rapidly to changed circumstances.Perfect competition.In this setting,the single nominal price,P,applies to all goods.,Macroeconomics Chapter 16,37,The Keynesian ModelSticky Nominal

34、 Wage Rates,Keynes focused on a case in which w was higher than its market-clearing level.This assumption will imply that the real wage rate,w/P,will be above its market-clearing value.,Macroeconomics Chapter 16,38,The Keynesian ModelSticky Nominal Wage Rates,Macroeconomics Chapter 16,39,The Keynesi

35、an ModelSticky Nominal Wage Rates,The excess of the quantity of labor supplied(at the given real wage rate,w/P)over L is called involuntary unemployment.,Macroeconomics Chapter 16,40,The Keynesian ModelSticky Nominal Wage Rates,Suppose,now,that a monetary expansion raises the price level,P.If the no

36、minal 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 labor demanded,Ld,and,thereby,increases labor input on the horizontal axis from L to L.,Macroeconomics Chapter 16,41,The Keynesian ModelSticky Nominal Wage Rates,Macroeconomics Chapt

37、er 16,42,The Keynesian ModelSticky Nominal Wage Rates,With sticky nominal wage rates,a monetary expansion raises labor input,L.The increase in L leads through the production function to an expansion of real GDP,Y.,Macroeconomics Chapter 16,43,The Keynesian ModelSticky Nominal Wage Rates,The Keynesia

38、n model is similar to the new Keynesian model in predicting that M and L would be procyclical.However,unlike the new Keynesian model,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 diff

39、iculty explaining the observed cyclical behavior of w/P.,Macroeconomics Chapter 16,44,Long-Term Contracts and Sticky Nominal Wage Rates,For 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 bet

40、ween firms and labor unions.More commonly,firms and workers have implicit contracts that specify in advance the nominal wage rate over some period,often a fiscal or calendar year.,Macroeconomics Chapter 16,45,Long-Term Contracts and Sticky Nominal Wage Rates,Suppose that an employer and employee agr

41、ee 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-clearing 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.,Macroeconomic

42、s Chapter 16,46,Long-Term Contracts and Sticky Nominal Wage Rates,When the contract expires,the employer and employee agree on a new nominal 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,mistak

43、es in the setting of w for this yeardue perhaps to underestimation of inflationtend not to be repeated the next year.,Macroeconomics Chapter 16,47,Long-Term Contracts and Sticky Nominal Wage Rates,At any point in time,the economy has an array of existing labor contracts,each of which specifies a nom

44、inal wage rate,w,that likely deviates somewhat from the market clearing value,w.Some of these agreements have w greater than w,and others have w less than w.,Macroeconomics Chapter 16,48,Long-Term Contracts and Sticky Nominal Wage Rates,Important empirical works:Ahmed(1987):index contractsOlivei et

45、al.(2007):shocks in different seasons have different effect.,Macroeconomics Chapter 16,49,Long-Term Contracts and Sticky Nominal Wage Rates,An important lesson from the contracting approach:Stickiness of the nominal wage rate,w,need not lead to the unemployment and underproduction that appears in th

46、e Keynesian model.,Macroeconomics Chapter 16,50,Extra:IS-LM model,r,I,S,S(y),I(r),Macroeconomics Chapter 16,51,Extra:IS-LM model,r,Y,Macroeconomics Chapter 16,52,Extra:IS-LM model,i=r,M/P,Assume now that P is fixed,Macroeconomics Chapter 16,53,Extra:IS-LM model,r,Y,Monetary policy:M increases,Macroe

47、conomics Chapter 16,54,Extra:IS-LM model,r,Y,Equilibrium:,Monetary policy:M increases,Macroeconomics Chapter 16,55,Extra:AD-AS model,r,Y,Aggregate Demand:,M fixed and P decreases,LM curve moves down,R decreases andY increases,Macroeconomics Chapter 16,56,Extra:AD-AS model,P,Y,Aggregate Demand:,P decreases andY increases,Macroeconomics Chapter 16,57,Extra:AD-AS model,P,Y,Aggregate Supply:,Long run:Y is fixedShort run:P is fixed,Macroeconomics Chapter 16,58,Extra:AD-AS model,r,Y,Aggregate Supply:,Long run:Y is fixedShort run:P is fixed,Macroeconomics Chapter 16,59,Extra:AD-AS model,P,Y,AD-AS:,