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1、全球视角宏观经济学课件,The approach of MacroeconomicsThe basic approach of Macroeconomics is to look at the overall trends in the economy. Special summary measures of economic activity -GNP, the saving rate, or the consumer price index- give the “big picture” of changes and trends.These overall macroeconomic m
2、easures provide the basic equipment that allows macroeconomists to focus on the dominant changes in the economy.,How do economists do their job? First, try to understand on a theoretical level the decision processes of individual firms and households.Second, try to explain the overall behavior of th
3、e economy by aggregating, or adding up, all the decisions of the individual households and firms in the economy.Third, giving empirical content to theory by collecting and analyzing actual macroeconomic data.,Some of the key questions addressed by macroeconomics,The most important single measure of
4、production in the economy is the GNP. Economic growth and business cyclesUnemployment is a second key variable that macroeconomics investigates.A third key variable that interests macroeconomists is the inflation rate.The fourth major variable that macroeconomists look at is the trade balance.,Macro
5、economics in historical perspective,The creation of macroeconomics Economic statisticians began to collect and systematize aggregate data which provided the scientific basis for macroeconomic investigations. The careful identification of business cycle as a recurrent economic phenomenon. The Great D
6、epression A new theoretical framework to explain the Great Depression proposed by Keynes.,The development of macroeconomics Keynesian and neo-Keynesian Main idea Keyness policy recommendation is the major tool of promoting economic growth. Non- Keynesian In fact, to many economists, it began to appe
7、ar that stabilization policies were actually a major source of renewed instability. A “counterrevolution” began. Monetarism and its central idea. New classical macroeconomics: Lucas and Barro. Advocates of the real business-cycle theory.,Providing a broader framework for macroeconomic analysis,The g
8、eneral theory is limited to short-term economic fluctuations and stabilization policies.Our analysis is pushed further by providing an especially broad view of macroeconomics. Beside the attention on short-term economic fluctuations and stabilization policies, we focus more attention on other centra
9、l concerns of macroeconomics,such as the determination of economic growth rate, or balance of payment, etc. Considerable attention has been given to the differences in economic institutions in different countries in order that we discover a more general macroeconomic theory.,Chapter 2 Basic Concepts
10、 in Macroeconomics,Looking at different measures of aggregate income and outcome and their interrelationship.The process of aggregating across many different goods and services requires some common unit of measure: the role of price and price indexes.A subject that permeates much of discussion in ma
11、croeconomics:Flows and Stocks Two factors that influence the Intertemporal decisions of economic agents:Interest Rates and Present Value.Another factor that is vital in understanding decision making across time periods: expectations,GDP and GNP,What are GDP and GNP?How to calculate them? interrelati
12、onship of them GNP = GDPNFPGNP per capita and economic well-being,Real Versus Nominal Variables,The construction of price indexes Consumer price index or consumer price deflator Pct = w1(P1tP10) + w2(P2t P20) + + WN(PNt PN0) Ct = nominal consumption expenditure Pct = Pct Ct Pct Deflator for investme
13、nt spending (PI), government spending (PG), exports (PX), and imports (Pm),Real GDPTo calculate real production, we think of the GDP of the economy as equal to the product of “average” price level in the economy, multiplied by the level of real production in the economy. GDP = PQHow to calculate Q ?
14、 We start with the definition of Nominal GDP as the sum of final expenditures throughout the economy. Then, we use the price indexes for consumption, investment, government spending, exports and imports to calculate a time series of real expenditures for each of these categories. Finally, we can get
15、 Q by adding up the sum of final expenditures of these categories.,How can we get P ? Once getting real GDP, Q, then we can compute the GDP price deflator P using the formula as follow: P = GDPQGenerally, we get Real GDP by using the formula as follow: Q = GDP P,Flows and Stocks in Macroeconomy,A fl
16、ow is an economic magnitude measured as a rate per unit of time.A stock is an economic magnitude measured at a point of time. Investment and the capital stockSaving and wealthThe current account and net international investment positionDeficit and the stock of public debt,Some Intertemporal Aspects
17、of Macroeconomics: Interest Rates and Present Values,Many key macroeconomics issues involve choices that not only take place in time but that involve decisions about timing. We call the choices involve later as intertemporal choice.Two crucial elements in the analysis of intertemporal decisions Inte
18、rest rates and net present valuesUsing interest rates, we can translate a given time path of money in the future into a present value today. an economic magnitude measured,The Role of Expectation,At the time that economic agents make intertemporal choices, they are generally uncertain about the futu
19、re, so they have to formulate some expectations about the future.How do economic agents actually formulate their expectations ?Static expectations Next year is going to be like this year. Adaptive expectations Individuals update their expectations about future depending on the extent to which their
20、expectations about present period turned out to be wrong. Rational expectation Individuals make efficient use of all available information. What economic model the individuals is using and just what economic information he or she has at hand.,Chapter 3 Output Determination: Introducing Aggregate Sup
21、ply and Aggregate Demand,Macroeconomics as the study of economic fluctuationsThe Determination of aggregate supplyThe classical approach to aggregate supplyThe Keynesian approach to aggregate supplyThe determination of aggregate demandEquilibrium of aggregate supply and aggregate demandAggregate sup
22、ply and demand in the short run and the long run,Macroeconomics as the study of economic fluctuations,Economic fluctuations have been a central concern of macroeconomicsEconomic fluctuations: output and employment fluctuations Unemployment ratePotential output, current output and output gap When emp
23、loyment fluctuates, so does output, since output is produced using labor inputs. Just as we measure the extent to which employment falls short of the full-employment level, we also can measure the extent to which output falls short of the level that would be produced if all labor were fully employed
24、.,Economic performance is not only measured in terms of the general trend of output, but also in terms of whether the output gap is increasing or decreasing. Okuns law There is a great regularity that a reduction of unemployment of 1 percent of labor force in the US was associated with a rise in GNP
25、 and fall in the output gap of 3 percent.Business cycle Unlike periods of sustained unemployment, business cycles represent shorter-term fluctuations of output and employment, typically lasting 3-4 years. A key feature of business cycles is that important macroeconomic variables-output, prices, inve
26、stment, business profits, and various monetary variables-tend to move together in a systematic fashion.,The Determination of aggregate supply,Aggregate supply Definition Aggregate supply is the total amount of output that firms and households choose to provide, given the pattern of wages and prices
27、in the economy. Optimal supply decision In fact, supply decision bases not only on current wages and prices, but also on expectations about future wages and prices.,Formulation of aggregate supplyThe Formulation of aggregate supply is complicated by the fact that there are many kinds of goods in the
28、 economy, produced by a very large number of firms and households.Our theoretical framework ignores these complications and assumes that the economy produces a single output.The production Function QQ (K, L, ) In the equation, output is a function of the capital and labor used in production and of t
29、he state of technology.,The production function has two characteristics: An increase in the amount of any input will make output go up. We assume that the marginal productivity of each factor declines as more of that factor is used with a fixed amount of the other factor.,B,Q=(K0,L),Q,L,Q,Q(K1K0),Q(
30、K1),L,MPL,L,MPL(K0),MPL(K1 K0),(a) Production function,(b) Marginal productivity of labor,The demand for labor and the output supply function The firm should hire labor until the marginal product of labor input equals the real wage.,w/p, MPL,(w/p)a,(w/p)b,La,Lb,L,We can summarize these findings by w
31、riting the demand for labor as a function of real wage and the levels of capital and technology: LD = LD(w/P, K, ) Using the labor-demand schedule. We can now derive an output supply schedule which shows the amount of output the profit-maximizing firm will supply at each level of w/p, K, and . QS =
32、QS LD(w/P, K, ) ， K, Note that QS is a negative function of w/p for an “indirect” reason.,Note also that QS is a positive function of K and ,for direct and indirect reasons. More simply, output supply is a negative function of w/p and a positive function of K and : QS = QS (w/P, K, )The Supply of La
33、bor The supply schedule for labor, LS Labor-supply decision: Household must choose between supplying labor and enjoying leisure, the so-called Labor-leisure decision.,Assumptions A worker must choose only between labor and leisure and in which he consumes all his wage earnings,which are his only sou
34、rce of income. The worker can choose to work any number of hours per day. UL = UL(C, L),C,L,UL2,UL1,UL0,L,C0,L,C1, C0,A,B,How much labor and consumption workers actually choose depends both on the utility function and on the real wage level.,C0 = (w/p) 0,C1 =3 (w/p) 0,C,L,Z1(w/p) 1 (w/p) 0 ,Z0 (w/p)
35、 0 ,1,2,3,C,L,UL2,UL1,Z1(w/p) 1 ,Z2(w/p) 2 ,C2,C1,(w/p),L,(w/p) 1,(w/p) 2,L 1,L 2,Substitution effect and Income effect Substitution effect means that each hour of leisure represents a greater amount of forgone consumption of goods when the real wage goes up. With leisure more expensive, households
36、“substitute” away from it and choose longer working hours. Income effect works to reduce labor supply when wages increase. The effect of a rise in wages on the supply of labor is theoretically ambiguous: the substitution effect tends to increase L, the income effect tends to decrease L. The relative
37、 influence of these two effects depends on household preferences.,The Classical Approach to Aggregate Supply,We already derived the Aggregate supply function, the demand for labor, and the supply of labor. Now we combine these and summarize the results in an aggregate supply curve.The Main idea of c
38、lassical approach For any price level, the nominal wage is fully flexible and adjusts to keep the supply of labor and the demand for labor equilibrated. Thus, the real wage is determined so as to clear the labor market.,Q,L,Qf,Q(K0, L),(w/p),L,Lf,LD,LS,P,Q,QS,Deriving the aggregate supply curve How
39、does the supply of aggregate output respond when the price level increase?,Q,L,(w/p),L,P,Q,Unemployment in the classical approach Amendments to the basic model One amendment allows for the fact that some people may choose voluntarily to be unemployed, at least for short periods of time. A second ame
40、ndment emphasizes that various forces in the labor market- laws, institutions, traditions- may prevent the real wage from moving to its full-employment level. If the real wage is stuck above the full-employment level, the unemployment results.,The Keynesian approach to aggregate supply Assumption: N
41、ominal wages and prices do not adjust quickly to maintain labor-market equilibrium. Sticky wages Long-term labor contracts As the price level(P) rises, the real wage falls, the desired level of labor input goes up, the desired level of output supply also rises. As a result, the aggregate supply curv
42、e is upward sloping.,Involuntary unemployment Involuntary unemployment is that some people who are willing to work at the wage received by other workers of comparable ability cannot do so. Why does involuntary unemployment arise? Nominal wage rigidity(Keynesian) Real wage rigidity(classical theory)A
43、ggregate Supply: a summary classical aggregate supply Keynesian aggregate supply extreme Keynesian aggregate supply,Qs,Qs,Qs,P,Q,Q,Q,The determination of aggregate demand The equilibrium level of output and the price level over an entire economy is determined by the interaction of aggregate supply a
44、nd aggregate demand. The structure of aggregate demand with a closed economy QD = C + I + G Aggregate demand curve Real Balance Effect One immediate effect of a price increase is to reduce the real value of money held by the public.,If people hold a given amount of currency and bank balances and the
45、 price level rises,they will be able to buy fewer goods with their money.,P,Q,B,A,P1,P0,QD1,QD0,In an open economy, aggregate demand is the total amount of domestic goods demanded at the given level of prices by both domestic and foreign purchasers. The aggregate demand schedule in the open economy
46、is still down-word-slope.In the open economy, as in the closed economy, a rise in the price level tends to cause a fall in aggregate demand. A rise in domestic prices compared with foreign prices makes it more expensive to buy domestic goods and relatively less expensive to buy foreign goods.,The Eq
47、uilibrium of Aggregate Supply And Aggregate DemandThe aggregate supply-aggregate demand framework is useful apparatus for determining the equilibrium of output and the price level. We can use this framework to study the effects of specific economic policies as well as of external shocks on the equil
48、ibrium levels of Q and P. Output market equilibrium is given by the intersection of the aggregate demand curve and aggregate supply schedule. This equilibrium will also determine the level of employment in the economy.,Equilibrated level of output does not signify the optimal level of output. There
49、might by output gap.Change on equilibrium: Demand sideAggregate demand expansion Changes in monetary, fiscal, and exchange-rate policies shift the position of aggregate demand schedule. Expansionary monetary, and fiscal policies and devaluated exchange-rate policy can result in aggregate demand expa
50、nsion,P,A demand expansion in the classical case,Q,QS,QD,QD,P1,P0,Qo,A demand expansion in the Keynesian case,P,Q,QD,QD,P1,P0,QS,Qo,Q1,A demand expansion in the Keynesian extreme case,P,Q,QD,QD,P,QS,Qo,Q1,-,Under classical conditions, a rise in aggregate demand leads only to a rise in prices, with n
