巴罗 宏观经济学

1、整理课件1Inflation, Money Growth, and Interest RatesC h a p t e r 1 1整理课件2Cross-Country Data on Inflation and Money GrowthKey equation: Ms = P L(Y, i)Two possible reasons of inflation:lDecrease of real demand for moneylIncrease of money supply整理课件3Cross-Country Data on Inflation and Money GrowthInflatio

2、n rates and money growth rates for 82 countries from 1960 to 2000. We measure the price level, P, by the consumer price index (CPI). We use the CPI, rather than the GDP deflator, because of data availability.整理课件4整理课件5整理课件6整理课件7Cross-Country Data on Inflation and Money GrowthHighlightslThe inflation

3、 rate was greater than 0 for all countries from 1960 to 2000lThe growth rate of nominal currency was greater than 0 for all countries from 1960 to 2000.lThere is a broad cross-sectional range for the inflation rates and the growth rates of money.整理课件8Cross-Country Data on Inflation and Money GrowthH

4、ighlightslThe median inflation rate from 1960 to 2000 was 8.3% per year, with 30 countries exceeding 10%. lFor the growth rate of nominal currency, the median was 11.6% per year, with 50 above 10%整理课件9Cross-Country Data on Inflation and Money GrowthHighlightslIn most countries, the growth rate of no

5、minal currency, M, exceeded the growth rate of prices.lFor a country that has a high inflation rate in one period to have a high inflation rate in another period.lStrong positive association between the inflation rate and the growth rate of nominal currency.整理课件10Cross-Country Data on Inflation and

6、Money Growth整理课件11Cross-Country Data on Inflation and Money GrowthOne lesson from the cross-country data is that, to understand inflation, we have to include money growth as a central part of the analysis.lMilton Friedmans famous dictum: “Inflation is always and everywhere a monetary phenomenon.” 整理

7、课件12Inflation and Interest RatesActual and Expected InflationlLet be the inflation rate. The inflation rate from year 1 to year 2, 1, is the ratio of the change in the price level to the initial price level.l1 = ( P2 P1)/ P1l1 = P1/ P1整理课件13Inflation and Interest RatesActual and Expected Inflationl1

8、 = ( P2 P1)/ P1l1 = P1/ P1l1 P1 = P2 P1lP2 = ( 1 +1) P1整理课件14Inflation and Interest RatesActual and Expected InflationlSince the future is unknown, households have to form forecasts or expectations of inflation. lDenote by e1 the expectation of the inflation rate 1.lThe actual inflation rate, 1, wil

9、l usually deviate from its expectation, e1, and the forecast erroror unexpected inflationwill be nonzero.整理课件15Inflation and Interest RatesActual and Expected InflationlHouseholds try to keep the errors as small as possible. Therefore, they use available information on past inflation and other varia

10、bles to avoid systematic mistakes. lExpectations formed this way are called rational expectations.整理课件16Inflation and Interest RatesReal and Nominal Interest RateslThe dollar value of assets held as bonds rises over the year by the factor 1 + i1. The interest rate i1 is the dollar or nominal interes

11、t rate because i1 determines the change over time in the nominal value of assets held as bonds.整理课件17Inflation and Interest Rates整理课件18Inflation and Interest RatesReal and Nominal Interest RateslThe Real interest rate to be the rate at which the real value of assets held as bonds changes over time.l

12、dollar assets in year2 = ( dollar assets in year1)(1+ i1)lP2 = P1 ( 1 + 1)整理课件19Inflation and Interest RatesReal and Nominal Interest Ratesl(dollar assets in year2/P2 )= (dollar assets in year1/P1) (1+i1)/(1+1)lreal assets in year2 = (real assets in year1) (1+i1)/(1+1)整理课件20Inflation and Interest Ra

13、tesReal and Nominal Interest RateslSince the real interest rate, denoted by r1, is the rate at which assets held as bonds change in real value:l(1+r1) = (1+i1)/(1+1)整理课件21Inflation and Interest RatesReal and Nominal Interest Rateslr1 = i1 1 r11the cross term, r1 1, which tends to be small;lreal inte

14、rest rate= nominal interest rate inflation rater1 = i1 1整理课件22Inflation and Interest RatesFisher Equationi = r +Fisher Effect i 整理课件23Inflation and Interest RatesThe Real Interest Rate and Intertemporal SubstitutionlWhen the inflation rate, , is not zero, it is the real interest rate, r, rather than

15、 the nominal rate, i, that matters for intertemporal substitution.整理课件24Inflation and Interest RatesActual and Expected Real Interest RateslThe expected inflation rate determines the expected real interest rate, ret lret = it etlexpected real interest rate= nominal interest rate expected inflation r

16、ate整理课件25Inflation and Interest RatesMeasuring expected inflationlAsk a sample of people about their expectations.lUse the hypothesis of rational expectations, which says that expectations correspond to optimal forecasts, given the available information. Then use statistical techniques to gauge thes

17、e optimal forecasts. lUse market data to infer expectations of inflation整理课件26Inflation and Interest RateslMeasuring expected inflationLivingston SurveyAsk a sample of people（50 economists） about their expectations.整理课件27Inflation and Interest Rates整理课件28Inflation and Interest Rates整理课件29Inflation a

18、nd Interest RateslMeasuring expected inflationIndexed bonds, real interest rates, and expected inflation ratesIndexed government bonds, which adjust nominal payouts of interest and principal for changes in consumer-price indexes. These bonds guarantee the real interest rate over the maturity of each

19、 issue. 整理课件30Inflation and Interest Rates整理课件31Inflation and Interest Rates整理课件32Inflation and Interest RatesInterest Rates on Moneylreal interest rate on money= nominal interest rate on money tlreal interest rate on money = t整理课件33Inflation in the Equilibrium Business-Cycle ModelGoalslTo see how i

20、nflation affects our conclusions about the determination of real variables, including real GDP, consumption and investment, quantities of labor and capital services, the real wage rate, and the real rental price.lTo understand the causes of inflation.整理课件34Inflation in the Equilibrium Business-Cycle

21、 ModelAssume fully anticipated inflation, so that the inflation rate, t, equals the expected rate, et .Extend the equilibrium business-cycle model to allow for money growth.整理课件35Inflation in the Equilibrium Business-Cycle ModelAssume the government prints new currency and gives it to people.lThey r

22、eceive a transfer payment from the government.lThe payments are lump-sum transfers, meaning that the amount received is independent of how much the household consumes and works, how much money the household holds, and so on.整理课件36Inflation in the Equilibrium Business-Cycle ModelIntertemporal-Substit

23、ution EffectslThe expected real interest rate, ret , has intertemporal-substitution effects on consumption and labor supply. lTherefore, for given it, a change in t will have these intertemporal-substitution effects.整理课件37Inflation in the Equilibrium Business-Cycle ModelBonds and Capitalli = (R/P) (

24、)lReplace the nominal interest rate on bonds, i, by the real rate, r,lr = (R/P) ()整理课件38Inflation in the Equilibrium Business-Cycle ModelInterest Rates and the Demand for MoneylThe tradeoff between earning assets and holding money is( i ) () = ilTherefore, the nominal interest rate, i, still determi

25、nes the cost of holding money rather than earning assets. We can therefore still describe real money demand by the functionMd / P = L( Y, i )整理课件39Inflation in the Equilibrium Business-Cycle ModelInterest Rates and the Demand for MoneylIt is the real interest rate, r, that has intertemporal-substitu

26、tion effects on consumption and labor supply.lIt is the nominal interest, i, that influences the real demand for money, Md/P.整理课件40Inflation in the Equilibrium Business-Cycle Model整理课件41Inflation in the Equilibrium Business-Cycle Model整理课件42Inflation in the Equilibrium Business-Cycle ModelInflation

27、and the Real EconomylA change in the inflation rate, , does not shift the demand or supply curve for capital services. Therefore, ( R/P) * and (K) * do not change.lA change in the inflation rate, , does not shift the demand or supply curve for labor. Therefore, ( w/ P) * and L* do not change.整理课件43I

28、nflation in the Equilibrium Business-Cycle ModelInflation and the Real EconomylReal GDP, Y, is determined by the production functionY= A F( K, L)lWe conclude that a change in does not influence real GDP, Y.整理课件44Inflation in the Equilibrium Business-Cycle ModelInflation and the Real EconomylThe real

29、 rental price, R/P, and the capital utilization rate, , determine the real rate of return from owning capital, (R/P) (), and therefore the real interest rate, r, r = ( R/ P) () .lSince R/P and are unchanged, we find that a change in the inflation rate, , does not affect the real interest rate, r.整理课

30、件45Inflation in the Equilibrium Business-Cycle ModelInflation and the Real EconomylIf we continue to ignore income effects from inflation, , we know that C does not change.lSince Y is fixed, we conclude that I does not change.整理课件46Inflation in the Equilibrium Business-Cycle ModelWe have found that

31、the time paths of money growth and inflation do not affect a group of real variables. This group comprises real GDP, Y; inputs of labor and capital services, L and K; consumption and investment, C and I; the real wage rate, w/P; the real rental price, R/P; and the real interest rate, r. The neutrali

32、ty of money apply, as an approximation, to the entire path of money growth. 整理课件47Inflation in the Equilibrium Business-Cycle ModelMoney Growth, Inflation, and the Nominal Interest RatelAnalyze how the time path of the nominal quantity of money, Mt, determines the time path of the price level, Pt, a

33、nd, hence, the inflation rate,t.lWe also assume for now that Yt and rt are constant over time.整理课件48Inflation in the Equilibrium Business-Cycle ModelMoney Growth, Inflation, and the Nominal Interest RatelMt =Mt+1Mtlt = Mt/MtlMt+1 = (1+t)Mtlt = Pt/ Ptlt = (Pt+1Pt)/PtlPt+1 = (1+t)Pt整理课件49Inflation in

34、the Equilibrium Business-Cycle ModelMoney Growth, Inflation, and the Nominal Interest RatelShow thatWhen Mt grows steadily at the rate , the price level, Pt, will also grow steadily at the rate . = 整理课件50Inflation in the Equilibrium Business-Cycle ModelMoney Growth, Inflation, and the Nominal Intere

35、st RatelThe real quantity of money demanded, L(Y, i), does not vary over time.real GDP, Y, is fixed.i = r+ i = r+ lSince we assumed that r and are fixed, i is unchanging. Since Y and i are fixed, we have verified that the real quantity of money demanded, L(Y, i), is unchanging.整理课件51Inflation in the

36、 Equilibrium Business-Cycle ModelMoney Growth, Inflation, and the Nominal Interest RatelThe level of real money demanded, L(Y, i), equals the unchanging level of real money balances, Mt/Pt .L(Y, i) and Mt/Pt are both fixed over time. Therefore, if the levels of the two variables are equal in the cur

37、rent year, year 1,they will remain equal in every future year.整理课件52Inflation in the Equilibrium Business-Cycle ModelMoney Growth, Inflation, and the Nominal Interest RatelDetermination of price level:P1 = M1 / L( Y, i)lt, is the constant = .整理课件53Inflation in the Equilibrium Business-Cycle ModelMon

38、ey Growth, Inflation, and the Nominal Interest RatelThe inflation rate, , equals the unchanging growth rate of money, .lReal money balances, Mt/Pt, are fixed over time.lThe nominal interest rate, i, equals r + , where r is the unchanging real interest rate.整理课件54Inflation in the Equilibrium Business

39、-Cycle ModelMoney Growth, Inflation, and the Nominal Interest RatelThe real quantity of money demanded, L(Y, i), is fixed over time, where Y is the unchanging real GDP.lP1 = M1 / L( Y, i)整理课件55Inflation in the Equilibrium Business-Cycle ModelA Trend in the Real Demand for MoneylAssume that L(Y, i) g

40、rows steadily at the constant rate . This growth might reflect long-term growth of real GDP整理课件56Inflation in the Equilibrium Business-Cycle ModelA Trend in the Real Demand for MoneylReal money balances, Mt/Pt, increase because of growth in the numerator, Mt, at the rate , but decrease because of growth in the denominator, Pt, at the rate .lgrowth rate of Mt/ Pt = 整理课件57Inflation in the Equilibrium Business-Cycle ModelA Trend in the Real Demand for MoneylIf L(Y, i) grows at rate , Mt