宏观经济学 斯蒂芬威廉森chap11

1 / 205第11章 包含投资的实际跨期模型11.1 复习笔记一、典型消费者1．基本分析典型消费者在当期和未来的每一时期作出工作-闲暇决策，在当期作出消费-储蓄决策。

（1）典型消费者预算约束①基本假定a ．典型消费者在每一时期有h 单位的时间，并在每一时期都将该时间划分为工作时间和闲暇时间；b ．w 表示当期实际工资，w ′表示未来实际工资，r 表示实际利率，消费者当期和未来向政府缴纳的一次总付税，分别为T 和T ′；c ．把w 、w ′和r 视为给定，该典型消费者是价格接受者。

从消费者的角度看，税收也是给定的。

2 / 205②预算约束a ．当期预算约束当期，典型消费者挣得实际工资收入w （h －l ），从典型企业那里获得股息收入π，纳税T ，当期可支配收入是w （h －l ）＋π－T 。

当期可支配收入被划分为消费和储蓄，储蓄的表现形式是债券，获取的一时期实际利率为r 。

在这种情形下，消费者通过发行债券来借款。

于是，消费者的当期预算约束是：C ＋S P ＝w （h －l ）＋π－Tb ．未来预算约束未来，典型消费者获取的实际工资收入w ′（h －l ′），从典型企业那里获得股息收入π′，向政府纳税T ′，并获得当期储蓄的本息（1＋r ）S p 。

由于未来是最后时期，又由于假定消费者没有留下遗产，因此未来消费者的全部财富都用于消费，于是，消费者的未来预算约束是：C ′＝w′（h －l ′）＋π′－T ′＋（1＋r ）S pc ．一生预算约束把S p 代入当期预算约束，可以得到典型消费者的一生预算约束3 / 205该预算约束表明，消费的现值（等式左边）等于一生可支配收入的现值（等式右边）。

（2）典型消费者的最优决策典型消费者的问题是，选择未来消费C ′、当期消费C 、当期闲暇时间l 和未来闲暇时间l ′，使其境况尽可能改善，同时又满足一生预算约束。

消费者的最优决策的三个边际条件：①消费者在当期作出工作—闲暇决策，因此，当消费者实现最优时，有： MRS l ，c ＝w亦即消费者通过选择当期闲暇和消费，使闲暇对消费的边际替代率等于当期实际工资，就可以实现最优。

Macroeconomics, 3e (Williamson)Chapter 4 C onsumer and Firm Behavior: The Work-Leisure Decision and Profit Maximization1) A dynamic decision is one thatA) i s made very quickly.B) i nvolves only the present.C) i nvolves only the future.D) i nvolves planning over more than one time period.Answer: DQuestion Status: P revious Edition2) A static decision is one thatA) i s made very slowly.B) i nvolves planning over one time period.C) i nvolves planning over exactly two time periods.D) i nvolves planning over more than one time period.Answer: BQuestion Status: P revious Edition3) W e typically assume thatA) b oth consumption and leisure are normal goods.B) c onsumption is a normal good and leisure is an inferior good.C) c onsumption is an inferior good and leisure is a normal good.D) b oth consumption and leisure are inferior goods.Answer: AQuestion Status: P revious Edition4) T he principle that consumers and firms optimizeA) i s not helpful because some economic agents may behave irrationally.B) i s helpful because it allows us to analyze how economic agents respond to changes intheir environment.C) o nly applies to perfectly competitive markets.D) i s helpful because it determines the available technology.Answer: BQuestion Status: P revious Edition5) T he consumer's work-leisure choice problem focuses on how a consumer's work-leisuredecision is affected by the consumer'sA) p references and productivity.B) p roductivity and psychology.C) p sychology and preferences.D) p references and constraints.Answer: DQuestion Status: P revious Edition6) L eisure includes all of the following exceptA) s leep.B) h ome yardwork.C) m arket work.D) r ecreational activities.Answer: CQuestion Status: P revious Edition7) I n macroeconomic analysis, the representative consumerA) d enotes the consumer with the average amount of income.B) p lays the role of a stand-in for all consumers in the economy.C) i s the consumer who bargains with firms for all workers in the economy.D) i s always a misleading fiction.Answer: BQuestion Status: P revious Edition8) A utility functionA) i s a stand-in for a more complicated function.B) i s useful only in microeconomics, not macroeconomics.C) c aptures the preferences of the representative household over consumption andleisure.D) c aptures the representative firm's ability to produce goods and services.Answer: CQuestion Status: P revious Edition9) W e use the concept of a representative agent becauseA) w e live in a democracy.B) t here is no taxation without representation.C) d istribution does not matter for our purposes.D) t here is not that much variation across agents anyway.Answer: CQuestion Status: N ew10) A consumption bundleA) i s a particular combination of consumption and leisure.B) o nly measures a quantity of goods and services, but not the amount of leisure.C) i s a method of bringing home consumption goods.D) m easures the quality of a particular good.Answer: AQuestion Status: P revious Edition11) A utility functionA) n eeds to measure the absolute level of happiness.B) n eeds to measure relative amounts of happiness for a single individual.C) h elps compare the relative happiness of two separate consumers.D) i s most useful if it can be influenced by others.Answer: BQuestion Status: P revious Edition12) W e use indifference curves becauseA) h ouseholds on average do not care.B) t hey help represent preferences.C) h ouseholds sometimes make mistakes.D) t hey formalize the production process.Answer: BQuestion Status: N ew13) T he preferences of the representative consumer over consumption and leisure arerepresented by use of aA) p roduction function.B) u tility function.C) b enefit function.D) p reference function.Answer: BQuestion Status: P revious Edition14) W e assume that the representative consumer's preferences exhibit the properties thatA) t hey evolve over time and that more is always preferred to less.B) m ore is preferred to less and that the consumer prefers diversity.C) t he consumer likes diversity and that more is sometimes preferred to less.D) m ore is sometimes preferred to less and that consumption and leisure are both normalgoods.Answer: BQuestion Status: P revious Edition15) W hat did we assume about household preferences?A) H ouseholds prefer more to less.B) H ouseholds like money.C) H ouseholds dislike taxes.D) H ouseholds care about others.Answer: AQuestion Status: N ew16) A consumer is said to be indifferent between two consumption bundlesA) w hen the consumer doesn't care about his or her consumption bundle.B) w hen the two bundles provide equal amounts of utility.C) w hen the consumer chooses the bundles equally often.D) w hen the consumer is indecisive.Answer: BQuestion Status: P revious Edition17) W e assume that the representative consumer's preferences exhibit the properties thatA) t hey are convex and that more is always preferred to less.B) m ore is always preferred to less and that each consumer has one strictly favorite good.C) e ach consumer has one strictly preferred good and that consumption and leisure areboth normal goods.D) c onsumption and leisure are both normal goods and that the consumer likes diversityin his or her consumption bundle.Answer: DQuestion Status: P revious Edition18) I n the (consumption,leisure) space, indifference curves as we have assumed them areA) d ownward sloping and bowed out of the origin.B) d ownward sloping and bowed towards the origin.C) u pward sloping and bowed out of the origin.D) u pward sloping and bowed towards the origin.Answer: BQuestion Status: N ew19) I n the (consumption,leisure) space, indifference curves as we have assumed them have theproperty of presenting the highest levels of satisfactionA) i n the north-east corner.B) i n the south-east corner.C) i n the north-west corner.D) i n the south-west corner.Answer: AQuestion Status: N ew20) A good is normal for a consumer ifA) i t is always consumed in a consistent quantity.B) i ts consumption rises when income rises.C) i ts consumption falls when income rises.D) s ome minimal level of the good must be consumed to assure the consumer's survival.Answer: BQuestion Status: P revious Edition21) W e assume leisure is a normal good. This implies thatA) a n increase in taxes decreases the demand for leisure.B) h ouseholds maximize utility.C) p references over consumption are well defined.D) a n increase in the wage increases demand for leisure.Answer: AQuestion Status: N ew22) A good is inferior for a consumer ifA) i t is never included in his or her consumption bundle.B) i ts consumption rises when income rises.C) i ts consumption falls when income rises.D) s ome minimal level of the good must be consumed to assure the consumer's survival.Answer: CQuestion Status: P revious Edition23) A consumption bundleA) i s a particular combination of consumption and leisure.B) o nly measures a quantity of goods and services, but not the amount of leisure.C) i s a method of bringing home consumption goods.D) m easures the quality of a particular good.Answer: AQuestion Status: N ew24) A n indifference curveA) c onnects a set of consumption bundles among which the consumer is indifferent.B) i s only useful in analyzing apathetic consumers.C) c onnects a set of consumers who each have the same preferences.D) i s only useful in microeconomics.Answer: AQuestion Status: P revious Edition25) T wo key properties of indifference curves are that an indifference curve slopesA) u pward and is bowed out from the origin.B) d ownward and is bowed out from the origin.C) u pward and is bowed in toward the origin.D) d ownward and is bowed in toward the origin.Answer: DQuestion Status: P revious Edition26) T he fact that indifference curves are downward slopingA) i s not true.B) f ollows from the fact that more is preferred to less.C) f ollows from the property that the consumer likes diversity in his or her consumptionbundle.D) f ollows from the property that consumption and leisure are normal goods.Answer: BQuestion Status: P revious Edition27) T he fact that indifference curves are bowed in toward the originA) i s not true.B) f ollows from the fact that more is preferred to less.C) f ollows from the property that the consumer likes diversity in his or her consumptionbundle.D) f ollows from the property that consumption and leisure are normal goods.Answer: CQuestion Status: P revious Edition28) T he marginal rate of substitutionA) c an be computed by measuring the slope of the indifference curve.B) c an be computed by measuring the curvature of the indifference curve.C) c annot be deduced from the properties of the indifference curve.D) c an only be computed if we know the prices of all goods.Answer: AQuestion Status: P revious Edition29) T he property of diminishing marginal rate of substitution follows from the property that theindifference curve isA) d ownward sloping.B) u pward sloping.C) b owed in toward the origin.D) b owed out from the origin.Answer: CQuestion Status: P revious Edition30) T he representative consumer acts competitivelyA) w hen he or she can haggle for a lower price.B) w hen he or she is a price-taker.C) w hen he or she is a price-maker.D) i f the consumer is large relative to the size of the market.Answer: BQuestion Status: P revious Edition31) W hen consumers act as price-takers, we say that they behaveA) c ooperatively.B) c ompetitively.C) m onopsonistically.D) i rrationally.Answer: BQuestion Status: P revious Edition32) A barter economyA) c annot be a market economy.B) i s an economy without monetary exchange.C) i s an economy with no business firms.D) i s not a competitive economy.Answer: BQuestion Status: P revious Edition33) A n economy without monetary exchange is calledA) a primitive economy.B) a barter economy.C) a socialist economy.D) a n autarky economy.Answer: BQuestion Status: P revious Edition34) T he time constraint for the consumer isA) t he amount of time for decision making.B) e xpressed as leisure time - time spent working = total time available.C) e xpressed as leisure time - sleep time = time spent working.D) e xpressed as leisure time + time spent working = total time available.Answer: DQuestion Status: P revious Edition35) T he real wage denotesA) t he number of units of consumption goods that can be exchanged for one unit of labortime.B) t he number of units of labor time that can be exchanged for one unit of consumptiongoods.C) t he number of units of labor time that can be exchanged for one unit of leisure time.D) t he number of units of leisure time that can be exchanged for one unit of labor time.Answer: AQuestion Status: P revious Edition36) A lump-sum tax is a tax thatA) c an be avoided by strategic behavior.B) d oes not depend on the actions of the economic agent being taxed.C) d oes not depend on the actions of the government.D) d istorts economic decisions.Answer: BQuestion Status: P revious Edition37) I n a one-period economyA) c onsumption equals disposable income.B) c onsumption equals disposable income plus the value of non-market work.C) s avings is always positive.D) c onsumers may increase their consumption by borrowing.Answer: AQuestion Status: P revious Edition38) A consumer's real disposable income equalsA) w age income plus consumption expenditures.B) w age income plus profit income minus taxes.C) t otal income minus profit income minus taxes.D) t otal income minus wage income minus taxes.Answer: BQuestion Status: P revious Edition39) I n a one-period economy, real consumptionA) i s always less than disposable income.B) i s typically greater than disposable income.C) i s exactly equal to disposable income.D) c an be greater than, less than, or equal to disposable income.Answer: CQuestion Status: P revious Edition40) I n a one-period economy, all of the following are equivalent expressions of the budgetconstraint exceptA) C= w(N S+l) +π-T.B) C=wN S+π-T.C) C=w(h - l)+π-T.D) C=wl=wh+π-T.Answer: AQuestion Status: P revious Edition41) W ith consumption on the vertical axis and leisure on the horizontal axis, the slope of thebudget line is equal toA) w.B) -w.C) π.D) -π.Answer: BQuestion Status: P revious Edition42) T he vertical intercept of the consumer's budget line is equal toA)h+()Twπ−.B) w h +π-T.C) c+ w(l - h).D) π- T.Answer: BQuestion Status: P revious Edition43) A n increase in taxes has the following impact on the budget constraintA) a parallel move down.B) a parallel move up.C) a tilting to the left.D) a tilting to the right.Answer: AQuestion Status: N ew44) T he household budget constraint may have a kink becauseA) t here is uncertainty.B) h ouseholds prefer diversity.C) h ouseholds may substitute consumption for leisure, or the reverse.D) l eisure is limited by the number of available hours.Answer: DQuestion Status: N ew45) T he optimal consumption bundle is the point representing a consumption-leisure pair thatis on theA) l owest possible indifference curve and is on or outside the consumer's budgetconstraint.B) l owest possible indifference curve and is on or inside the consumer's budgetconstraint.C) h ighest possible indifference curve and is on or outside the consumer's budgetconstraint.D) h ighest possible indifference curve and is on or inside the consumer's budgetconstraint.Answer: DQuestion Status: P revious Edition46) A t the optimal consumption bundle, the marginal rate of substitution of leisure forconsumption is equal toA) t he real wage and the budget line is tangent to an indifference curve.B) m inus the real wage and the budget line is tangent to the indifference curve.C) t he real wage and the budget line intersects the indifference curve.D) m inus the real wage and the budget line intersects the indifference curve.Answer: AQuestion Status: P revious Edition47) A defense for the assumption that consumers maximize is thatA) c onsumers never make mistakes.B) m istakes by the consumer are not likely to last for a long time.C) i t allows for many possible outcomes.D) m istaken consumers may receive counseling from the government.Answer: BQuestion Status: P revious Edition48) A n increase in real dividend income minus taxes representsA) a pure substitution effect.B) a pure income effect.C) a combination of income and substitution effects.D) n either a pure income effect nor a pure substitution effect.Answer: BQuestion Status: P revious Edition49) A pure positive income shock leads toA) a n increase in leisure and consumption.B) a n increase in leisure and work.C) a n increase in work and consumption.D) a n increase in leisure and taxes.Answer: AQuestion Status: N ew50) W hen consumption and leisure are both normal goods, after an increase in real dividendincome minus taxation, the rational consumerA) i ncreases consumption and increases leisure.B) i ncreases consumption and reduces leisure.C) r educes consumption and increases leisure.D) r educes consumption and reduces leisure.Answer: AQuestion Status: P revious Edition51) W hen consumption and leisure are both normal goods, after an increase in real dividendincome minus taxation, the rational consumerA) i ncreases consumption and increases labor supply.B) i ncreases consumption and reduces labor supply.C) r educes consumption and increases labor supply.D) r educes consumption and reduces labor supply.Answer: BQuestion Status: P revious Edition52) A n increase in the real wageA) r epresents a pure substitution effect.B) r epresents a pure income effect.C) r epresents a combination of income and substitution effects.D) c auses a parallel shift in the consumer's budget line.Answer: CQuestion Status: P revious Edition53) A n increase in the real wageA) u nambiguously increases consumption and increases labor supply.B) i ncreases consumption and has an ambiguous effect on labor supply.C) h as an ambiguous effect on consumption and increases labor supply.D) h as an ambiguous effect on both consumption and labor supply.Answer: BQuestion Status: P revious Edition54) W hen the wage increases, the substitution effect in the household's choices leads toA) a decrease in consumption and leisure.B) a decrease in consumption and an increase in leisure.C) a n increase in consumption and a decrease in leisure.D) a n increase in consumption and leisure.Answer: CQuestion Status: N ew55) W hen the wage increases, the income effect on the household's choices leads toA) a decrease in consumption and leisure.B) a decrease in consumption and an increase in leisure.C) a n increase in consumption and a decrease in leisure.D) a n increase in consumption and leisure.Answer: DQuestion Status: N ew56) I n the United States during the period 1980-2006, there wasA) a n upward trend in both the real wage and average hours worked.B) a n upward trend in real wages, and a downward trend in average hours worked.C) a downward trend in real wages, and an upward trend in average hours worked.D) a downward in both real wages and average hours worked.Answer: BQuestion Status: R evised57) T he substitution effect measuresA) t he responses of quantities to changes in the relative prices of goods.B) t he responses of relative prices to changes in the demand for goods.C) h ow two goods can be used for the same purpose.D) t he responses of quantities to changes in the relative qualities of goods.Answer: AQuestion Status: N ew58) T he labor supply is increasing in the wage becauseA) t he substitution effect is larger than the income effect.B) t he income effect is larger than the substitution effect.C) t he production function is increasing in labor.D) t he marginal product of labor is decreasing.Answer: AQuestion Status: N ew59) A production function describes theA) t echnological possibilities for converting factor inputs into outputs.B) i ntellectual possibilities for converting factor inputs into outputs.C) a mount of resources available to the representative firm.D) a ctual process of converting factor inputs into outputs.Answer: AQuestion Status: P revious Edition60) In the production function, Y = zF(K, N d), total factor productivity isA) Y/K.B) Y/ N d.C) F/Y.D) z.Answer: DQuestion Status: P revious Edition61) C apital, K, encompassesA) m oney.B) m achinery.C) r esidential housing.D) k now-how.Answer: CQuestion Status: N ew62) T he marginal product of a factor of productionA) i s equal to the ratio of the amount of that factor of production to the amount of outputproduced.B) i s equal to the amount of additional output that can be produced with one additionalunit of each factor input.C) i s equal to the amount of additional output that can be produced with one additionalunit of that factor input, holding constant the quantities of the other factor inputs.D) a lways exceeds the average product of that factor input, holding constant thequantities of the other factor inputs.Answer: CQuestion Status: P revious Edition63) C onstant returns to scale means that, given any constant x > 0A) xY = zF(xK, xN d).B) xY > zF(xK, xN d).C) xY < zF(xK, xN d).D) xY = Z x F(K, N d).Answer: AQuestion Status: P revious Edition64) T he construct of a representative firm is most helpful in describing the behavior of all of thefirms in the economy whenA) t here are constant returns to scale.B) t here are increasing returns to scale.C) t here are decreasing returns to scale.D) t he marginal product of labor is increasing in the amount of labor input.Answer: AQuestion Status: P revious Edition65) A s the quantity of labor increases, the marginal product of laborA) i s constant.B) i ncreases.C) d ecreases.D) m ay either increase or decrease.Answer: CQuestion Status: P revious Edition66) A s the quantity of capital increases, the marginal product of capitalA) i s constant.B) i ncreases.C) d ecreases.D) m ay either increase or decrease.Answer: CQuestion Status: P revious Edition67) A s the quantity of capital increases, the marginal product of laborA) i s constant.B) i ncreases.C) d ecreases.D) m ay either increase or decrease.Answer: BQuestion Status: P revious Edition68) T he assumption that labor has a decreasing marginal return to production means that aslabor increasesA) o utput increases.B) t he wage increases.C) t he production function is concave.D) t he production function shifts upward.Answer: CQuestion Status: N ew69) T he production function is concave in labor becauseA) t he contribution to production of each additional unit of labor decreases.B) t he marginal product of labor is increasing.C) t he marginal product of capital is decreasing.D) t he labor demand is downward sloping.Answer: AQuestion Status: N ew70) A n increase in total factor productivity shifts the production functionA) u pward and increases the marginal product of labor.B) u pward and decreases the marginal product of labor.C) d ownward and increases the marginal product of labor.D) d ownward and decreases the marginal product of labor.Answer: AQuestion Status: P revious Edition71) O f the following, which is the least likely example of an increase in total factor productivity?A) t he introduction of the assembly lineB) t he invention of the personal computerC) g ood weatherD) a reduction in the relative price of energyAnswer: BQuestion Status: P revious Edition72) L ook at the production schedule of the Widget Company below:Number of workers 0 1 2 3 4 5Number of widgets 0 12 22 30 36 40What is the marginal product of the second worker?A) 8B) 10C) 12D) 22Answer: BQuestion Status: N ew73) L ook at the production schedule of the Widget Company below:Number of workers 0 1 2 3 4 5Number of widgets 0 12 22 30 36 40If the real wage is 7, how many workers should Widget Company hire?A) n oneB) 2C) 3D) 4Answer: CQuestion Status: N ew74) L ook at the production schedule below:Workers 0 1 2 3 4 5Output 0 45 80 100 130 165Which property of a standard production function does it violate?A) c onstant returns to scaleB) d ecreasing marginal product of capitalC) d ecreasing marginal product of laborD) p roduction increasing in laborAnswer: CQuestion Status: N ew75) L ook at the production schedule below:Workers 0 1 2 3 4 5Output 0 45 80 100 130 165Which worker violates a property of the standard production function?A) 1B) 2C) 3D) 4Answer: DQuestion Status: N ew76) W hich is a good example of an increase in total factor productivity?A) a tax cutB) g ood weatherC) a company reducing its workforceD) b etter credit conditionsAnswer: BQuestion Status: N ew77) T otal factor productivity encompassesA) l abor.B) c apital.C) o utput.D) k now-how.Answer: DQuestion Status: N ew78) A n increase in total factor productivityA) c hanges neither the slope nor the position of the production function.B) c hanges the slope but not the position of the production function.C) c hanges the position but not the slope of the production function.D) c hanges both the slope and the position of the production function.Answer: DQuestion Status: P revious Edition79) T he Solow residual is a measure ofA) a verage labor productivity.B) a verage capital productivity.C) t otal factor productivity.D) t he rate of growth of real GDP.Answer: CQuestion Status: P revious Edition80) T he profit-maximizing quantity of labor equates the marginal product of labor withA) t otal factor productivity.B) t he marginal product of capital.C) t he real wage.D) t he average product of labor.Answer: CQuestion Status: P revious Edition81) W hen the representative firm maximizes profits,A) i t sells as much as possible.B) t he wage equals average labor productivity.C) t he wage equals marginal labor productivity.D) b usiness taxes must be zero.Answer: CQuestion Status: N ew82) W hen the representative firm maximizes profitsA) p roduction is at its maximum.B) t he slope of the production function is at its flattest.C) l abor costs are minimized.D) t he marginal product of labor equals the wage.Answer: DQuestion Status: N ew83) S uppose the representative firm suddenly has less capital at its disposal. What happens tolabor demand?A) I t increases.B) I t stays the same.C) I t decreases.D) W e cannot tell.Answer: CQuestion Status: N ewThe questions below deal with the Widget Company, which produces widgets according to the following table.84) T he marginal product of the second widget worker hired isA) 2.B) 8.C) 10.D) 12.Answer: CQuestion Status: P revious Edition85) I f the real wage is equal to 7 widgets, and only an integer number of workers can be hired,the Widget company should hireA) 2 workers.B) 3 workers.C) 4 workers.D) 5 workers.Answer: BQuestion Status: P revious EditionThe questions below deal with the Gizmo Company, which has the following production function.86) T he marginal product of the fourth gizmo worker hired isA) 1.B) 3.C) 5.D) 10.Answer: CQuestion Status: P revious Edition87) I f the real wage is equal to 8 widgets, and only an integer number of workers can be hired,the Gizmo company should hireA) 2 workers.B) 3 workers.C) 4 workers.D) 5 workers.Answer: AQuestion Status: P revious Edition88) L abor demand is decreasing in the wage becauseA) t he substitution effect is larger than the income effect.B) t he income effect is larger than the substitution effect.C) t he production function is concave.D) t he marginal product of labor is increasing in labor.Answer: CQuestion Status: N ew。

Chapter 13International Trade in Goods and AssetsTeaching GoalsThere are two basic aspects to international trade. Trade in goods and services allows a nation to benefit from comparative advantage. In the absence of trade, competitive markets allow the economy to reach a Pareto optimum. At this optimum, the marginal rate of substitution for consumers is equal to the marginal rate of transformation in production. These marginal rates are reflected in market prices. If we open up an economy to trade, the country can improve its welfare as long as closed economy relative prices differ from the relative prices in the rest of the world. It does not matter in which direction this difference works. In either case, the representative consumer can reach an indifference curve that lies beyond the one reached in the absence of trade. This is the essence of gains to trade.The second aspect of trade involves trade in financial assets. A closed economy is required to exactly exhaust its total output in each period between consumption, investment, and government spending. An open economy can use either more or less than the output it produces in each period. Differences between production and absorption can occur when the current account is either in surplus or deficit. A common misimpression for students is to think of the current account balance as reflecting competition for sales by firms in different countries. A better insight into the current account balance comes from considering the additional option for consumption smoothing that comes from borrowing and lending activities with those in other countries. One clear case for the benefits of running a current account deficit is for a country that wants to increase its capital stock more quickly than would be possible in the absence of foreign borrowing. Classroom Discussion TopicsSupport for protectionist trade policies comes to the forefront from time to time. Ask students for arguments they have heard that rationalize tariffs or quotas. Ask them if they support such policies, or find the reasons given for protectionist sentiment compelling. What does fair trade as opposed to free trade mean? Guide them in the direction of finding market failures in international trade. Distinctions between free and fair trade only have meaning if there is monopoly power in the markets for traded goods, or if there are externalities that are complicated by the differing rules of different sovereign nations. Monopoly power may be involved in the steel and automotive industries. Is this a concern for students? Trade protection is also proposed because other nations have more lax environmental restrictions. Don’t we benefit from the decision of other countries to specialize in dirty industries?Trade policies usually boil down to attempts by those who are hurt by trade to seek compensation from those who benefit from trade. What are the likely differences in relative prices between a closed United States and the rest of the world? Much of recent concern has its roots in the fact that the value of skilled labor relative to unskilled labor is much higher in the rest of the world than it would be in a closed United States. Are trade policies a relatively efficient or inefficient means to affect the distribution of income? Are students able to see trade policy issues as economists see them? Encourage the students to couch their views of trade policies in the language of economics.Chapter 13 International Trade in Goods and Assets 129Another concern voiced in the popular press relates to the fact that the United States has been running consistent deficits in the current account balance. Are students concerned about the balance of payments? Why or why not? Remind the students that current account surpluses and deficits are equivalent tointernational borrowing and lending. Is it ever a good idea to try to prevent markets from functioning in a competitive manner? Be sure that they understand that encouraging exports and discouraging importscannot solve the problems inherent in the desire to smooth consumption and expand investment as long as the marginal product of capital exceeds the world real interest rate.Regarding modeling strategies, ask students how a closed economy differs from an open economy. With the representative agent construct, just splitting an economy in two would not yield anything interesting. There needs to be something different in the two parts: different realizations of shocks, differencecurrencies, different policies, etc. Also, discuss the distinction between a small open economy and a large open economy (à la two-country model).OutlineI. A Two-Good Model of a Small Open EconomyA. Introduction1. The Small Open Economy Assumption2. Terms of Trade3. The Real Exchange Rate4. The PPFB. Competitive Equilibrium without Trade1. Pareto Optimality: ,,a b a b MRS MRT =2. Efficiency in Consumption: ,,a b a b MRS p =3. Efficiency in Production: ,,a b a b MRT p =C. Effects of Trade1. International Price-Taking2. Efficiency in Consumption: ,a b ab MRS TOT =3. Efficiency in Production: ,a b ab MRT TOT =4. Comparative Advantage5. Trade and WelfareD. A Change in the Terms of Trade1. Trade Effects when Good a Is Imported2. Trade Effects when Good b Is ImportedII. A Two-Period Small Open EconomyA. The Intertemporal Budget ConstraintB. Response of the Current Account to Disturbances1. Current-Period Income and the Current Account2. Current Government Spending and the Current Account3. Taxes and the Current Account4. The Real Interest Rate and the Current AccountC. The Current Account and Consumption SmoothingD. The Twin Deficits130 Williamson • Macroeconomics, Third EditionIII. Production, Investment, and the Current AccountA. Output Supply and Output DemandB. Effects of Disturbances1. An Increase in the World Interest Rate: ,Y CA ↑↑2.A Temporary Increase in Government Spending: ,Y CA ↑↓ 3.A Permanent Increase in Government Spending: ,Y CA ↑↑ 4.An Increase in Current Total Factor Productivity: ,Y CA ↑↑ 5. An Increase in Future Total Factor Productivity: 0,Y CA Δ=↓C. Consumption, Investment, and the Current AccountTextbook Question SolutionsQuestions for Review1. A small open economy is an economy that does not affect the world price of goods.2. The small open economy model is useful in explaining events in the United States because it isrelatively simple, many of the conclusions drawn from the small open economy model are identical to those obtained from more complicated models, and the size of the U.S. economy as a fraction of worldwide GDP is shrinking.3. In the closed economy, the marginal rate of substitution between the two goods must equal themarginal rate of transformation between the two goods. Furthermore, consumption of each individual good must be equal to production of that good.4. In the open economy, the marginal rates of substitution and transformation between the two goodsmust equal the given terms of trade.5. The residents of an open economy must be better off. An open economy has all of the possibilities ofa closed economy, and its options are expanded with the opportunity to trade.6. Production of good a rises and production of good b falls. Consumption of good a falls, butconsumption of good b may either rise or fall.7. Production of good a rises and production of good b falls. Consumption of good b rises, butconsumption of good a may either rise or fall.8. The current account surplus depends upon current period income, current government spending,taxes, and the real interest rate.Chapter 13 International Trade in Goods and Assets 131 9. A current account deficit may help an economy to grow over time if the deficit is used to financeinvestment spending.10. The twin deficits refer to the simultaneous deficits in the government budget and the current account.The large government budget deficit was the result of a simultaneous increase in governmentspending and a reduction in taxes. Unless the reduction in government savings is matched by an equal or larger increase in private savings, the current account deficit must increase.11. An increase in the world real interest rate increases output, reduces absorption, and increases thecurrent account surplus.12. A temporary increase in government spending increases output, increases absorption, and decreasesthe current account surplus. A permanent increase in government spending increases output, has no effect on absorption, and increases the current account surplus.13. An increase in current total factor productivity increases output, has no effect on absorption, andincreases the current account surplus. An increase in future total factor productivity has no effect on output, increases absorption, and decreases the current account surplus.14. A current account deficit used to finance investment spending provides for a larger future capitalstock. The increased capital stock increases future output, which tends to reduce the future current deficit.Problems1. The change in preferences cannot change the terms of trade for a small open economy. Therefore,production of each good is unchanged. The shift in preferences implies increased consumption of good a, and reduced consumption of good b. If good a is originally imported, then imports andexports both increase. If good a is originally exported, then imports and exports both decrease.2. If the marginal rate of transformation increases for every quantity of good a, then there is a shift inthe production possibilities frontier. In particular, there is no change in the maximum amount of goodb that can be produced, so there is no change in the horizontal intercept. The rest of the PPP becomessteeper and lies everywhere else above the original PPP. Production of good b increases, butproduction of good a may either rise or fall. If the increase in the marginal rate of substitution rotated the original PPP around the original production point, then production of good a would decrease.The outward shift in the PPP produces a positive income effect. However, because there can be no change in the terms of trade, there can be no substitution effect in consumption. Consumption of goods a and b both increase. Suppose that, as a first approximation, that production of good a is unchanged. If good b is originally exported, then exports of good b increase along with imports of good a. If good b is originally imported, then imports of good b decrease along with exports ofgood a.132 Williamson • Macroeconomics, Third Edition3. Suppose that the economy starts out as in the figure below. The economy produces 1a units of good aand 1b units of good b . Consumers consume 2a units of good a and 2b units of good b . The economytherefore exports good b and imports good a . Now assume that a quota is placed on imports of good a , and that this quota is, in fact, a binding constraint. Denote the size of the quota as <32.b bThe budget line now becomes vertical at 3.b The new budget line is depicted in the figure below. Theeconomy continues to produce at point 11(,).a b Consumption is at point 33(,).a b Therefore, less of good a is imported and less of good b is exported. Consumers are definitely worse off. They are no longer able to consume at a point on indifference curve, 1.I They are forced to the less desirableindifference curve, 2.IChapter 13 International Trade in Goods and Assets 1334. Government spending with perfect-complements preferences.(a) The net amount of income available from domestic production net of government spending in thefirst period is equal to 100 − 15 = 85, and the net amount of income available from domesticproduction net of government spending in the second period is equal to 120 − 20 = 100. The budget constraint is given by:100851.1 1.1C C ′+=+ Setting first-period and second-period consumption equal, we find that consumption in bothperiods is equal to 92.14. The current account surplus is equal to domestic income, 100 minus consumption, 92.14, minus government spending, 15, so the current account is equal to –7.14, a deficit. The endowment point, E, and the consumption point, F, are depicted in the first figure below.134 Williamson • Macroeconomics, Third Edition(b) Net first-period income now falls to 75. The budget constraint is given by:100751.1 1.1C C ′+=+ Setting first-period and second-period consumption equal, we find that consumption in bothperiods is equal to 87.86. The current account surplus is equal to domestic income, 100 minus consumption, 87.86, minus government spending, 25, so the current account is equal to –12.86, a larger deficit. The endowment point, E, and the consumption point, F, are depicted in the second figure above.(c) In this problem, the increase in government spending leads to a larger current account deficit.The representative consumer increases her borrowing so that first-period consumption need not fall as much as the temporary increase in government spending.5. Different borrowing and lending rates.(a) For levels of first-period consumption less than Y – T , the consumer lends his private savings,and earns the world real rate of interest, r . For levels of first-period consumption greater thanY – T , the consumer must borrow at the higher real rate of interest, r *. The representativeconsumer’s budget line is bowed out, away from the origin. A change in r * steepens the part of the budget line where C > Y – T . If the consumer was originally a saver, the change in r * has no effect on consumption or the current account surplus. If the consumer was originally a borrower, the budget relevant portion of the line rotates through the point (,).Y T Y'T'−− The substitution effect of the change in r * implies lower first-period consumption and higher second-periodconsumption. The income effect of the change in r* decreases both first-period and second-period consumption. Since first-period consumption unambiguously decreases, the currentaccount surplus must increase.(b) A tax cut financed by government borrowing pushes the kink in the budget constraint to the right.If the representative consumer is a lender, there is no effect. If the representative consumer is a borrower, this represents a pure income effect. Both first-period and second-period consumption increase. If the current account is initially in balance, then the current account goes into deficit. The representative consumer is able to get to a higher indifference curve, so welfare increases. The government is able to pass along the ability to lend at the world real interest rate, so theadditional costs of borrowing are eliminated.6.Current account deficit policies.(a) If Ricardian equivalence holds, then the level of lump-sum taxation has no effect on the currentaccount. The first group of advisors would therefore be wrong. A tax on investment shifts theinvestment demand schedule to the left. The output supply curve is unchanged. The outputdemand curve continues to pass through the original equilibrium position at the given world real interest rate. Because investment has decreased, absorption decreases, so the current accountdeficit declines. Therefore, the best advice to take would be to adopt the investment tax.(b) The concern with the current account deficit is misguided in this instance. The deficit is beingused to finance investment spending. Over time, the increase in investment leads to a larger stock of capital, the output supply curve shifts to the right, and the current account deficit eventually disappears. If the policy is implemented, the stated objective could be met, but welfare would be lower, and the policy would continue to be needed, because it would be difficult for the economy to grow its way out of the situation that caused the deficit.Chapter 13 International Trade in Goods and Assets 135 7. The expected future increase in government spending decreases lifetime wealth. The output supplyschedule shifts to the right. At the unchanged real interest rate, investment is unchanged and both current and future consumption decrease. Absorption decreases and output increases, so the current account must increase.8. A persistent increase in total factor productivity would shift both the output supply curve and theoutput demand curve to the right. The supply curve shifts due to higher employment and higherproductivity. Investment demand increases due to the increase in expected future productivity.Consumption increases due to the increases in current and future income. The analysis of Chapter 11 argued that the shift in the supply curve would be larger than the combined effects of the changes in investment and consumption, so the current account balance would also increase. At the given world real interest rate, investment increases. At the given world real interest rate, the increase in domestic income increases consumption. These predictions are in line with the typical business cycle.However, this scenario is inconsistent with Figure 13.10 in the text. In the data, the current account is negatively correlated with output. In this example, output and the current account move in the same direction.9. The increase in future government spending reduces the present value of lifetime income. Laborsupply increases, so the output supply curve shifts to the right, and so output increases. Consumption spending decreases due the decrease in lifetime wealth. Investment is unchanged. Therefore, the current account surplus increases.。

宏观经济学-课后思考题答案_史蒂芬威廉森011Chapter 11Market-Clearing Models of the Business CycleTeaching GoalsPhysics has so far failed to provide a unified theory to explain all physical phenomena. Economics is even further away from achieving such a goal. Keynesian models, while still popular among many policymakers, do not do a very good job of explaining the source and the mechanism by which the typical business cycle comes to pass. Although business cycles are remarkable similar, they are not identical, and they appear to have multiple causes.Equilibrium theorists have proposed a number of business cycle explanations that are based upon microeconomic principles and need not rely on markets failing to equilibrate. Interestingly, in contrastto the most basic of classical models, these models often admit a constructive role for macroeconomic policymaking.The real business cycle model emphasizes the point that shocks to total factor productivity are persistent, and that business cycles may represent the optimal response to such shocks. The segmentation markets model realizes that not everyone participates in financials markets and thus some agents are primarily effected by open market operations. The coordination failure model recognizes the possibility that strategic complementarities generate a kind of externality in production. While all of these considerations may, to a greater or less extent, be important factors in macroeconomic performance, a model that simultaneously considered all of these possibilitieswould be too unwieldy to provide coherent insights. Nevertheless, all of the possibilities of these models shed light on some causes and means of propagating business cycles.Classroom Discussion TopicsThe material in this chapter concludes the study of business cycle phenomena and macroeconomic stabilization policy. At this point it may be useful to revisit students’ original thoughts and prejudices about the proper role of government policy. With so many competing models, how would the students run monetary and fiscal policy if it were their job to do so? Does macroeconomics offer too many competing models and too many points of view? It can be helpful to point out that there is no consensus among macroeconomists on this issue. Should policy be used on a routine basis to fine-tune the economy? Should policymakers simply try to avoid significant fluctuations in the policy instruments? Should aggressive policy measures be employed against very serious shocks like the Great Depression?108 Williamson ? Macroeconomics, Third EditionOutlineI. The Real Business Cycle ModelA. The Workings of the Real Business Cycle Model1. Persistence of the Solow Residual2. Effects of a Persistent Change in Total Factor Productivity3. Qualitative and Quantitative Replication of the Business Cycle FactsB. Real Business Cycles and the Behavior of the Money Supply1. Cyclical Properties of the Money Supplya. Nominal Money Is Procyclicalb. Nominal Money Leads Real GDP2. Endogenous M oneya. Behavior of Bank Deposit Moneyb. Central Banks and Price-Level Stabilization3. Statistical Causality and True CausalityC. Implications of the Real Business Cycle Model for Government Policy1. Money Is Neutral2. Government Spending Based on Optimal Provision of Public Goods3. Other Policy Goalsa. The Friedman Ruleb. The Smoothing of Tax DistortionsD. Critique of the Real Business Cycle Model1. Measurement of Total Factor Productivity2. Labor Hoarding3. Real Business C ycle Theory and the “Volker Recession”II. The Segmented Markets ModelA. Limited Participation in Financial MarketsB. The Workings of the Model1. The Liquidity Effect2. Money Demand as a Function of the Expected Interest Rate3. Money Supply Surprises Are Not NeutralC. Implications1. Real Impact2. Money Injection Increases GDP and Components3. Average Labor Productivity Is Counterfactually Countercyclical4. Central Bank Can Be Welfare Improving: It Alleviates Cash ConstraintsD. Critique1. Relies on Central Bank Fooling Agents2. Relies on Firms Being Cash ConstraintChapter 11 Market-Clearing Models of the Business Cycle 109III. A Keynesian Coordination Failure ModelA. The Workings of the Model1. Coordination Failures2. Strategic Complementarities3.M ultiple Equilibria4. Increasing Returns to ScaleB. The Coordination Failure Model: An Example1. The Downward-Sloping Goods Supply Curve2. Multiple Intersections of Goods Supply and Goods Demand3. SunspotsC. Predictions of the Coordination Failure Model1. Properties of “Good” and “Bad” Equilibria2. The Coordination Failure Model and the Business Cycle FactsD. Policy Implications of the Coordination Failure Model1. Achieving a Single Equilibrium2. Does Policy Improve Performance?E. Critique of the Coordination Failure Model1. Evidence of Increasing Returns2. Unobservable ExpectationsTextbook Question SolutionsQuestions for Review1. Macroeconomic models should be based onmicroeconomic principles. Equilibrium models are the most productive vehicles for studying macroeconomic phenomena.2. Although business cycles are remarkably similar, they may have many causes. Alternative businesscycle models offer insights into one or more key features of the economy and some aspects of the e conomy’s response to macroeconomic shocks. Policymakers need as much insight as possible to guide their actions.3. In the real business cycle model, persistent shocks to total factor productivity cause output tofluctuate.4. Although changes in the money supply change nominal prices in the real business cycle, they changeneither perceived nor actual relative prices. There is therefore no reason for firms or consumers to change their behavior.5. In the real business cycle model, changes in the money supply may be endogenous. In particular,when output increases due to a total factor productivity shock, the banking system is likely toincrease the quantity of deposit money, and the Fed may increase the monetary base in order tostabilize the aggregate price level.6. In the real business cycle model, firms and consumers in the economy make optimal responses tochanges in total factor productivity. Therefore, policy cannot improve matters, and may actually make matters worse.110 Williamson ? Macroeconomics, Third Edition7. The real business cycle provides a good explanation of the business cycle facts, both qualitatively andquantitatively.8. There are some phenomena that the real business cycle model cannot adequately explain. As oneexample, there is good evidence that the U.S. recession of 1981–82 was due to a monetary policy shock. The real business cycle model has no explanation of monetary nonneutrality.9. It is because it affects agents after they have made their money choices and, in this model, allows thefirm to adjust its activities that are cash constrained.10. Only if it does that intelligently. Purely random policy would be detrimental, as it would throw agentsoff their plans. But if it helps them as they face shocks, for example by alleviating cash constraints, then it is good stabilization policy. The central bank, however, needs to have very good information and needs to act quickly.11. Remarkably well, except for the countercyclical average labor productivity.12. Parties are more fun when a lot of people attend. If everyone believes that others will attend,everyone goes to the party and has a good time. However, if most people think that others are not going, they will also choose not to go, few people will show up and the party will be much lesssuccessful. The coordination failure arises because people may not be able to jointly decide whether they will attend.13. In the coordination failure model, business cycles may occur if consumers and firms are alternativelyoptimistic and pessimistic. Aggregate-level increasing returns to scale then set in to amplify the effects of such changes in attitude.14. The coordination failure model is an equilibrium model. In the absence of any other changes inbehavior, changes in the money supply change the aggregate price level, but they do not change relative prices. Therefore, consumers and firms continue to make the same choices.15. The coordination failure model does a very good job in fitting the facts of the typical business cycle.16. The choice of which model is better depends on how we interpret some of the more detailedevidence. However, both models may shed some light on some features of different business cycle events, and both models may offer some insights that may be useful for policymakers.Problems1. The response to a temporary change in government spending in the real business cycle model is thesame as the response to such a disturbance in the monetary intertemporal model, as the two models are equivalent. Government spending shocks in this model wrongly predict that consumption,investment, and the real wage are countercyclical. In response to a temporary increase in government spending, output increases and the real interest rate increases. Because the net effect on moneydemand is ambiguous, the effect on the price level is also ambiguous. Therefore, there can be no contradiction of model’s predictions on the cyclical behavior of the price level.Chapter 11 Market-Clearing Models of the Business Cycle 111 2. We already know that persistent increases in total factorproductivity are consistent with all of thebusiness cycle facts. As developed in the answer to problem 4, above, we noted that temporaryincreases in government spending were not consistent with several of the business cycle facts. If both disturbances are combined, the ability to fit the facts depends on which of the parts of the disturbance are stronger. In particular, if the increase in government spending produces a small increase in total factor productivity, then this type of disturbance will not fit the facts very well. For this type ofdisturbance to fit the business cycle facts, a small increase in government spending would need to generate a large increase in total factor productivity.3. Business optimism about future total factor productivity.(a) First consider the fundamental effects of the increase in expected future total factor productivity.Such a disturbance shifts the aggregate demand curve to the right. In the coordination failuremodel, this results in an increase in output and employment in the good equilibrium and adecrease in output and employment in the bad equilibrium. The increased optimism might alsomove the economy from the original bad equilibrium to the new good equilibrium.(b) Let us focus on the effects of changes in future total factor productivity on the good equilibrium.This disturbance shifts the aggregate demand curve to the right. The good equilibrium is at higher levels of output and employment, and a lower real interest rate. In the labor market, the reduction in the real interest rate also increases the real wagerate. The decrease in the real interest rateincreases consumption spending. The increase in the real interest rate likely mitigates, but doesnot reverse, the direction of the effect of the disturbance on investment. All of these effects areconsistent with the business cycle facts. Finally, the increase in output and the reduction in thereal interest rate both work to increase money demand. The price level therefore decreases, which is also consistent with the business cycle facts.(c) The increased optimism decreases the price level in the good equilibrium. Therefore, themonetary authority should increase the money supply when firms become more optimistic andreduce the money supply when firms become more pessimistic. Note that if the money supply isa sunspot variable, there may be a difficulty with reducing the money supply when firms becomemore pessimistic. This policy response is therefore consistent with the nominal money supplybeing procyclical. Such a change in the money supply may also shift the economy from the good equilibrium to the bad equilibrium, and this factor obviously greatly complicates the analysis.4. Announced policies in the segmented markets model.(a) In this case, the expected real interest rate r e is unaffected, despite the announcement, and moneysupply M s is reduced. This is equivalent to an unexpected decrease of the money supply, and we have the exact opposite situation from what is described in Figure 11.5 of the textbook.Thus, the interest rate and the price level will increase; employment, output, consumption, and investment all decrease.(b) As this announcement is believed, all agents will be able to react to it and there is no marketsegmentation. We are thus back to the monetary model of Chapter 10. Real aggregates areunaffected, only the price level decreases.(c) The price level changes more in the second situation, as there is no real impact that wouldcounterbalance it. Now to make its policy announcements more credible, the central bank would need to show consistently that it is acting like it said it would. This can, for example, be attained by sticking to a well-publicized rule.112 Williamson ? Macroeconomics, Third Edition5. We want to compare here a positive money supply shock as it affects economies a and b that areinitially at steady state. The shock is larger in economy a. The figures below build on Figure 11.5 from the textbook, the only difference being the amplitude of the shocks. The steady states are the same for both countries, with one exception: money demand is lower in country a due to the higher uncertainty about prices. Indeed, households do not like variations, thus all agents will use more banking services to avoid the larger consequences from price variations. The consequence is that all aggregates fluctuate more in country a. While the price level is initially higher in country a, it may fall below the one in the other country, depending on the difference in money demands between the two countries. But the price level fluctuates more for sure in country a. The figures belowillustrate this.Chapter 11 Market-Clearing Models of the Business Cycle 1136. If the money supply were the only variable that shifts the economy between the bad and good states,the monetary authority would need to increase the money supply only if the economy starts out in the bad state. However, once the good state is reached, there is no further need to make any changes in the money supply. Both models are therefore consistent with a predictable money supply as the best way to make consumers better off.On the other hand, if there was a disturbance that shifted the economy into the bad state, it would be optimal for the monetary authority to increase the money supply when output falls. In the money surprise model, changes in the money supply in response to disturbances can only make consumers worse off.7. The reduction in the demand for leisure implies a rightward shift in labor supply. This shift in laborsupply implies an equilibrium in the labor market with less employment and a decreased real wage.The aggregate supply curve therefore shifts to the left. The increase in the demand for consumption goods shifts the aggregate demand curve to the right. Therefore, in the good state, output increases and the real interest rate decreases. In the bad state, output decreases and the real interest rate increases.114 Williamson ? Macroeconomics, Third Edition8. The permanent increase in government spending does not affect the aggregate demand curve, becausethe increase in government spending generates an approximately equal decrease in consumption. The implied increase in taxes shifts the labor supply curve to the right. In the coordination failure model this produces a leftward shift in aggregate supply. Recall that the labor demand curve is upward sloping and steeper than the labor supply curve. A leftward shift in aggregate supply is depicted in the figure below.In the “good” equilibrium, output increases and the real interest rate decreases. That output increases requires that employment increase. The increase in employment moves the economy along the labor demand curve, so that the real wage rate must also increase. Finally, the increase in output combined with the decrease in the real interest rate implies that money demand shifts to the right, and so the price level decreases.In the “bad” equilibrium, output decreases and the real interest rate increases. That output decreases requires that employment decrease. The decrease in employment moves theeconomy along the labor demand curve, so that the real wage rate must also decrease. Finally, the decrease in output combined with the decrease in the real interest rate implies that money demand shifts to the left, and so the price level increases.Chapter 11 Market-Clearing Models of the Business Cycle 115 9. The effects of the decrease in the capital stock depend on the specific model we are working with.The effect of the decrease in capital in the real business cycle is depicted in the figure below.116 Williamson ? Macroeconomics, Third EditionThe real interest rate unambiguously increases. The diagramdepicts a case in which real outputdecreases. In this case, the demand for money unambiguously decreases, and so a decrease in the money supply is required to maintain price stability. If, on the other hand, the increase in investment demand is strong enough, then the aggregate demand curve may shift to the right by more than the shift to the left in aggregate supply. In this case, real output increases. If real output increases enough, then the demand for money may increase. This case would require an increase in the money supply.In the coordination failure model, the situation is more complex. The decrease in the capital stock shifts the aggregate production function downward, as in the figure below. The new aggregateproduction function is flatter, so that the aggregate labor demand curve shifts downward. Employment would therefore increase. The increase in employment coupled with the decrease in the capital stock, may either increase or decrease the level of output. If, as depicted in the figure below, output on net decreases, then the aggregate supply curve shifts to the left.Chapter 11 Market-Clearing Models of the Business Cycle 117 The decrease in the capital stock also shifts the aggregate demand curve to the right. If the aggregate supply curve shiftsto the left, then the situation is as depicted in the figure below. In the bad equilibrium, output decreases and the real interest rate increases. Money demand would therefore decrease, and the money supply would need to decrease to maintain price stability. In the good equilibrium, output increases and the real interest rate decreases. Money demand would increase, and so the money supply would need to increase to maintain price stability.。

Chapter 5A Closed-Economy One-PeriodMacroeconomic ModelTeaching GoalsThere are three key points to be learned from this chapter. The first point is that when we allow the consumers and firms that we studied in Chapter 4 to interact with each other and with the government, the economy is able to achieve equilibrium through price adjustment. In this particular case, the “price” is the relative price of leisure, the real wage. The second important point is that the equilibrium that markets settle upon is a favorable one, in the sense of Pareto optimality. This point is in keeping with Adam Smith’s notion that the “invisible hand” of self-interested individuals, meeting in a competitive market, can work for the common good. The third point is that we can directly discover the equilibrium position of a market economy by solving an economic planner problem. Although students may find this point to be somewhat arcane, stress the point that it will be much simpler to solve problems (e.g., exam problems) by working with a planner problem as opposed to directly solving general equilibrium problems. The students, however, need to be aware when this solution method is not applicable. The new section about the Laffer curve is a good way to show when social and private optima do not coincide.Once students have mastered the mechanics of the model, the two problems for which this model is best suited are the analyses of changes in government spending and total factor productivity. In working these problems, stress the applicability of these results to historical applications and as a guide to understanding current events.A key tactic of the textbook’s approach is the critical assessment of the usefulness and credibility of competing models. Therefore, it is important to stress the extent to which models fit the facts. Does this model fit the facts of long-run growth? Does this model fit the facts of the typical business cycle? These kinds of questions come up again and again in the course of macroeconomic study. Stress again and again that scientific study needs to relate to observations, in our case the stylized facts of Chapter 2.Classroom Discussion TopicsAn alternative approach to this material is to start with the example of Robinson Crusoe (or Castaway, Gilligan’s Island, etc.). Does an isolated individual have any economic choices? What would guide these choices? Would you rather be on an island with a more plentiful food supply? A pure income effect can then be presented in the form of extra food (or a volleyball) washing up on shore, or in the form of “pirates” (government?) demanding tribute. An increase in total factor productivity can be in the form of obtaining a fishing net or a ladder to climb coconut trees. A change in capital can be the consequence of a hurricane, etc.The next step would be to ask the students about the likely consequences of additional individuals on the island. If they are all identical, and there are no economies to team production, will there be any reason for markets to exist? Could a market improve things? How and why? Typically, markets improve things only to the extent that people are different. However, these types of differences are what we are willing to ignore when we adopt the fiction of a representative consumer.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 43OutlineI. Com p etitive EquilibriumA. A One-Period Model1. No Borrowing or Lending2. G = TB. Equilibrium M odeling1. Endogenous Variables2. Exogenous Variables3. Hypothetical ExperimentsC. Properties of a Competitive Equilibrium1. Representative Consumer Maximizes Utility Subject to Budget Constraint2. Representative Firm Maximizes Profits3. M arkets Clear4. Government Budget Constraint Satisfied5. ,,l C l C N w MRS MRT MP ===II. O p timalityA. Pareto OptimalityB. Welfare Theorems1. 1st Theorem: A Competitive Equilibrium Can Be Pareto Optimal2. 2nd Theorem: A Pareto Optimum Can Be a Competitive EquilibriumC. Inefficiencies1. Externalities2. Distorting Taxes3. M onopoly PowerD. Using the Second Theorem1. Pareto Optima Are Easier to Identify2. Effects of Disturbances on Pareto OptimaIII. Effects of an Increase in Government SpendingA. Impact Effect1. Parallel Downward Shift in PPF2. Pure Income EffectB. Equilibrium Effects1. Reduced Consumption2. Reduced Leisure and Increased Hours of Work3. Increased Output4. Lower Real WageC. Crowding-OutD. Government Spending a Source of Business Cycles?1. Government Spending Shocks Wrongly Predict Countercyclical Consumption2. Government Spending Shocks Wrongly Predict Countercyclical Real Wages44 Williamson • Macroeconomics, Third EditionIV. Effects of an Increase in Total Factor ProductivityA. Impact Effect1. Upward Shift in PPF2. Steeper PPF3. Income and Substitution EffectsB. Equilibrium Effects1. Increased Consumption2. Leisure and Hours Worked May Rise or Fall3. Increased Output4. Higher Real WageC. Productivity and Long-Run Growth1. Consumption Grows over Time2. Hours Worked Remain about Constant3. Output Increases over Time4. Real Wages Rise over TimeD. Productivity as Source of Business Cycles?1. Consumption Is Procyclical2. Cyclical Properties of Hours Workeda. Procyclical Hours Worked Is a Business Cycle Factb. Need Strong Substitution Effect to Predict Procyclical Hoursc. Intertemporal Substitution of Leisure3. Increased Output Defines the Cycle4. Procyclical Real Wage RateV. Income Tax Revenue and the Laffer CurveA. Tax Revenue1. The Tax Base Depends on the Proportional Tax Rate2. The Laffer Curve Measures Tax Revenue as a Function of the Tax Rate3. Unless the Tax Rate Is Optimal, Two Tax Rates Yield the Same Tax Revenue4. Supply-Side Economists Claim the U.S. Economy Is at the Bad Tax Rate5. Empirical Evidence Tends to Prove Supply-Side Economists WrongTextbook Question SolutionsQuestions for Review1. A closed economy is easier to work with. Opening the economy does not change most of theproperties of an economy. The closed economy is the correct model for the world as a whole.2. Government levies taxes and purchases consumption goods.3. In a one-period model, there can be no borrowing or lending. There is therefore no way to finance agovernment deficit.4. Endogenous variables: C, N s, N d, T, Y, and w.5. Exogenous variables: G, z, K.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 456. The representative consumer chooses C and N s to maximize utility.The representative firm chooses N d to maximize profits.M arket-clearing: .s d N N N == Government budget constraint: T = G .7. The slope of the production possibilities frontier is equal to .N MP − The slope of the productionpossibilities frontier is also identified as ,,l C MRT − where ,l C MRT is identified as the marginal rate oftransformation between leisure and consumption.8. The competitive equilibrium is Pareto optimal because it lies at a tangency point between theproduction possibilities frontier and a representative consumer’s indifference curve.9. The first theorem: A competitive equilibrium can be Pareto optimal. This theorem assures us that thecompetitive equilibrium is a good outcome. The second theorem: A Pareto optimum is a competitive equilibrium. This theorem allows us to directly analyze Pareto optima with the assurance that these points are also competitive equilibriums. The second theorem is useful because Pareto Optima are often easier to work with than competitive equilibriums.10. Externalities, noncompetitive behavior, and distorting taxes.11. , ,, , and .G Y C N l w ↑⇒↑↓↑↓↓ 12. Government competes with the private sector in buying goods. An increase in government spendingimplies a negative wealth effect, which results in lower consumption.13. , , and .z Y C w ↑⇒↑↑↑ The sign of the effects on N and l are ambiguous.14. The substitution effect of an increase in z is that the representative consumer works more hours. Theincome effect of an increase in z is that the representative household works more hours. The sign of the net effect is ambiguous.15. A distorting tax makes that households equalize their marginal rate of substitution between leisureand consumption to the after tax wage, which is different from the before tax wage that firms equalize their marginal rate of transformation to. Thus, one cannot achieve the Pareto optimum where the same wage (before tax) is equal to both marginal rates above.16. The Laffer curve takes into account that higher proportional tax rates give incentives to households towork less. While tax revenue increases with the tax rate for a given tax base, that tax base is reduced by the tax rate.17. When the income tax rate falls, households are willing to supply additional labor more in suchquantities that the tax base increases more than what the tax rate decreases, thus increasing taxrevenue.46 Williamson • Macroeconomics, Third EditionProblems1. Although we often think about the negative externalities of congestion and pollution in cities, theremay also be some positive externalities. A concentrated population is better able to support the arts and professional sports; cities typically have a greater variety of good restaurants, etc. Perhaps a more basic issue is that there may be some increasing returns to scale at low output levels that makeindustrial production more costly in small towns. There may also be externalities in production in being located close to other producers. One example would be the financial industry in financial centers like New York, London, Tokyo, etc. Another example would be large city medical centers that enhance coordination between primary physicians and specialists.One market test of whether productivity is higher in cities would be to look at the wages in cities versus the wages in smaller towns and rural areas. Wages are often higher in cities for individuals of comparable skills. Market efficiency suggests that the higher wages be reflective of a higher marginal product of labor, and that the higher wages compensate those choosing to live in cities for thenegative externalities that they face.2. In a one period model, taxes must be exactly equal to government spending. A reduction in taxes istherefore equivalent to a reduction in government spending. The result is exactly opposite of the case of an increase in government spending that is presented in the text. A reduction in governmentspending induces a pure income effect that induces the consumer to consume more and work less. At lower employment, the equilibrium real wage is higher because the marginal product of labor rises when employment falls. Output falls, consumption rises, employment falls and the real wage rises.3. The only impact effect of this disturbance is to lower the capital stock. Therefore, the productionpossibility frontier shifts down and the marginal product of labor falls (PPF is flatter).(a) The reduction in the capital stock is depicted in the figure below. The economy starts at point Aon PPF1. The reduction in the capital stock shifts the production possibilities frontier to PPF2.Because PPF2 is flatter, there is a substitution effect that moves the consumer to point D. Theconsumer consumes less of the consumption good and consumes more leisure. Less leisure also means that the consumer works more. Because the production possibilities frontier shifts down, there is also an income effect. The income effect implies less consumption and less leisure (more work). On net, consumption must fall, but leisure could decrease, remain the same, or increase, depending on the relative strengths of the income and substitution effect. The real wage must also fall. To see this, we must remember that, in equilibrium, the real wage must equal the marginal rate of substitution. The substitution effect implies a lower marginal rate of substitution. The income effect is a parallel shift in the production possibilities frontier. As the income effect increases the amount of employment, marginal product of labor must fall from point D topoint B. This reinforces the reduction in the marginal rate of substitution from point A to point D.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 47(b) Changes in the capital stock are not likely candidates for the source of the typical business cycle.While it is easy to construct examples of precipitous declines in capital, it is more difficult toimagine sudden increases in the capital stock. The capital stock usually trends upward, and thisupward trend is important for economic growth. However, the amount of new capital generatedby a higher level of investment over the course of a few quarters, of a few years, is very small in comparison to the existing stock of capital. On the other hand, a natural disaster that decreasesthe stock of capital implies lower output and consumption, and also implies lower real wages,which are all features of the typical business cycle contraction.4. Government Productivity. First consider the benchmark case in which 1,z= and there is no effect of changes in z on government activities. Now suppose that z increases. This case of an increase in z isdepicted in the figure below. The original production possibilities frontier is labeled PPF1 and thecompetitive equilibrium is at point A. If the increase in z only affects the economy through thechange in (,),zF K N then the new production possibilities frontier is PPF2. The diagram shows acase in which the income and substitution effects on leisure exactly cancel out, and the economy moves to point B. The equation for the production possibilities frontier is (,).C zF K h l T=−− In the benchmark case, T G= and so we have (,).C zF K h l G=−− For this problem, /T G z=, and so the production possibilities frontier is given by (,)/.C zF K h l G z=−− When 1,z= the two PPFs coincide. When z increases, the vertical intercept of the PPF increases by /.G zΔ Therefore, the newPPF is PPF3 in the figure below. The competitive equilibrium is at point C. There is an additionalincome effect that provides an additional increase in equilibrium consumption, and a reinforced income effect that tend to make leisure increase. Therefore, relative to the benchmark case, there is a larger increase in consumption, and either a smaller decrease in leisure or a larger increase in leisure.48 Williamson • Macroeconomics, Third Edition5. Change in preferences.(a) At the margin, the consumer decides that leisure is more preferred to consumption. That is, theconsumer now requires a bigger increase in consumption to willingly work more (consume lessleisure). In more intuitive language, the consumer is lazier.(b) To work out the effects of this change in tastes, we refer to the figure below. The productionpossibility frontier in this example is unchanged. The consumer now picks a new point at which one of the flatter indifference curves is tangent to the production possibilities frontier. That is,equilibrium will shift from point A to point B. Consumption falls and leisure rises. Therefore, the consumer works less and produces less. Because employment has fallen, it also must be the case that the real wage increases.(c) This disturbance, which some might characterize as a contagious outbreak of laziness, wouldhave the appearance of a recession, as output and employment both fall. The consequentreduction in consumption is also consistent with a typical recession. However, in this case thereal wage would rise, which is inconsistent with the business cycle facts. Therefore, this type ofpreference change is not a cause of recessions.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 496. Production-enhancing aspects of government spending.(a) The increase in government spending in this example has two separate effects on the productionpossibilities frontier. First, the increase in government spending from G1 to G2implies a paralleldownward shift in the production possibilities frontier. Second, the productive nature of government spending is equivalent to an increase in total factor productivity that shifts the production possibilities frontier upward and increases its slope. The figure below draws theoriginal production possibilities frontier as PPF1 and the new production possibilities frontier asPPF2. If the production-enhancing aspects of the increase in government spending are largeenough, representative consumer utility could rise, as in this figure.(b) There are three effects at work in this example. First, there is a negative income effect from theincrease in taxes needed to pay for the increased government spending. This effect tends to lower both consumption and leisure. Second, there is a substitution effect due to the productive effect of the increase in G, which is drawn as the movement from point A to point D. This effect tends to increase both consumption and leisure. Third, there is a positive income effect from theincrease in G on productivity. This effect tends to increase both consumption and leisure. In the figure above, the movement from point D to point B is the net effect of the two income effects. In general, consumption may rise or fall, and leisure may rise or fall. The overall effect on output is the same as in any increase in total factor productivity. Output surely rises.50 Williamson • Macroeconomics, Third Edition7. The fact that government spending make firms more productive is similar to adding G to theproduction function. There are now two effects to an increase in government expenses: the standard crowding out of consumption, and now also an efficiency effect on production.(a) The figure below illustrates a particular situation where the welfare of the household is improved,as illustrated by a shift to the north-east of the indifference curve. The equilibrium shifts fromA toB as the PPF is lowered by the additional government expenses but is also getting steeperthanks to the same government expenses.(b) From previous results, we know that output increases with the increase in government expenses.This is now reinforced as G increases production efficiency. Regarding consumption and leisure, without this new effect, we obtained that an increase in G lead to a negative income effect andthus to decreases in both consumption and leisure. But as the real wage went down, there wasalso a substitution effect leading to an additional decrease in consumption and increase in leisure.The new effect on the production function adds opposite effects: a positive income effect and awage increase, thus possibly reversing, or not, anything that was concluded without the impact ofG on production.Chapter 5 A Closed-Economy One-Period Macroeconomic Model 51 8. We need to analyze each case separately. Start with the good equilibrium. As government expensesincrease, more tax revenue needs to be raised, and thus the tax rate needs to be increased. As shown in the figure below, this tilts down the linear PPF. The new equilibrium leads to a lower indifferencecurve. This leads to a negative income effect and a lower wage (remember, it is z(1 − t)), thus a substitution effect. The income effect lowers consumption and leisure, the substitution effectdecreases consumption and increases leisure. All in all, consumption is lower and leisure is higher, as we know that the substitution effect dominates the income effect. This means that the labor supply is reduced, and thus equilibrium labor and output.The story is different in the bad equilibrium. To increase tax revenue, one needs to reduce the tax rate. Then all the changes discussed above are exactly in the opposite direction.9. We know from previous analysis that an improvement in total factor productivity pushes up the PPF,and thus leads to an increase in consumption, a decrease in leisure, and thus an increase in thequantity of labor supplied. This increases the tax base, and thus allows to reduce the tax rate toachieve the same tax revenue, or in other words, it pushes the left portion of the Laffer curve to the left. The reduction in the tax rate has then a further impact on the variables of interest: as we saw in question 7, first part with a reversal of all signs: consumption increases even more and leisure decrease yet more, leading to an even higher quantity of labor. All in all, as both labor and total factor productivity increase, output increases.。

第1章导论一、名词解释1．宏观经济学（macroeconomics）答：宏观经济学是与“微观经济学”相对而言的，指研究整体经济现象，包括通货膨胀、失业和经济增长的经济学。

宏观经济学以国民经济总体作为考察对象，研究经济生活中有关总量的决定与变动，解释失业、通货膨胀、经济增长与波动、国际收支与汇率的决定与变动等经济中的宏观整体问题，所以又称之为总量经济学。

宏观经济学的中心和基础是总供给—总需求模型。

具体来说，宏观经济学主要包括总需求理论、总供给理论、失业与通货膨胀理论、经济周期与经济增长理论、开放经济理论、宏观经济政策等内容。

对宏观经济问题进行分析与研究的历史十分悠久，但现代意义上的宏观经济学直到20世纪30年代才得以形成和发展起来。

宏观经济学诞生的标志是凯恩斯于1936年出版的《就业、利息和货币通论》。

宏观经济学在20世纪30年代奠定基础，二战后逐步走向成熟并得到广泛应用，20世纪60年代后的“滞胀”问题使凯恩斯主义的统治地位受到严重挑战并形成了货币主义、供给学派、理性预期学派对立争论的局面，20世纪90年代新凯恩斯主义的形成又使国家干预思想占据主流。

宏观经济学是当代发展最为迅猛，应用最为广泛，因而也是最为重要的经济学学科之一。

2．国内生产总值（gross domestic product，GDP）答：国内生产总值指一个国家（地区）领土范围内，本国（地区）居民和外国居民在一定时期内（通常为一年）所生产和提供的最终物品和劳务的市场价值。

GDP一般通过支出法、收入法、生产法三种方法进行核算。

用支出法计算的国内生产总值等于消费、投资、政府支出和净出口之和；用收入法计算的国内生产总值等于工资、利息、租金、利润、间接税和企业转移支付和折旧之和。

用生产法计算的国内生产总值等于一个国家在一定时期内所生产的所有产出和服务的价值总和减去生产过程中所使用的中间产品的价值总和。

GDP是一国范围内生产的最终产品的市场价值，因此是一个地域概念，而与此相联系的国民生产总值（GNP）则是一个国民概念，乃指某国国民所拥有的全部生产要素所生产的最终产品的市场价值。

1 / 37第1章 导 论1.1 复习笔记一、宏观经济学1．宏观经济学的研究对象宏观经济学的研究对象是众多经济主体的行为。

它关注的是消费者和企业的总体行为、政府的行为、单个国家的经济活动总水平、各国间的经济影响，以及财政政策和货币政策的效应。

2．宏观经济学与微观经济学的联系与区别（1）联系微观经济学家与宏观经济学家都在使用非常相似的研究工具。

宏观经济学家用来描述消费者与企业的行为、目标与约束，以及他们之间如何相互影响的经济模型，是根据微观经济学原理建立起来的，而且在分析这些模型和拟合数据时通常都用微观经济学家所用的方法。

2 / 37（2）区别宏观经济学的研究对象有别于微观经济学，宏观经济学侧重于总量研究，强调的问题主要是长期增长和经济周期。

微观经济学主要针对单个消费者或者企业的行为选择。

二、国内生产总值、经济增长与经济周期1．国内生产总值（gross domestic product ，GDP ）国内生产总值是一国在某一特定时期在境内生产的产品和服务的数量。

GDP 也表示那些对国内产出作出贡献的人挣得的收入总量。

实际GDP 是针对通货膨胀进行调整后的总产出衡量指标。

2．经济增长（long-run growth ）经济增长率是一个国家当年国内生产总值对比往年的增长率。

经济正增长一般被认为是整体经济景气的表现。

长期增长是指一国长期的生产能力和平均生活水平的提高。

3．经济周期（business cycles ）经济周期是指总体经济的短期上下波动，或经济的繁荣与衰退。

3 / 37三、宏观经济模型1．宏观经济模型及其假设宏观经济模型是用来解释长期经济增长、经济周期存在的原因、以及经济政策在宏观经济中应发挥的作用的模型。

确切的说，宏观经济模型的基本构造是用来描述下列特征的：（1）经济中相互影响的消费者与企业。

（2）消费者希望消费的一组商品。

（3）消费者对商品的偏好。

（4）企业生产商品可采用的技术。

（5）可利用的资源。

Chapter 6Economic Growth: Malthus and SolowTeaching GoalsStudents easily take for granted the much more abundant standard of living of today as opposed to 20, 50, or 100 years ago. Sometimes it is easier to remind students of what their ancestors had to do without, rather than simply referring to per capita income levels over time. Recessions come and go, and yet economic growth swamps the lost output we endure during hard times.The typical student begins study of economic growth against the backdrop of the recent growth experience of the United States. The current standard of living in the United States vastly surpasses the current standard of living in most countries and would have been unimaginable anywhere in the world before the advent of the industrial revolution. Until about 1800, the world economy produced little more than a subsistence level of income for any but the richest individuals. Growth in per capita income was nonexistent. The Malthusian model of growth explains the tendency of increases in population to dilute any gains in productivity.The industrial revolution introduced the possibility of sustained growth in per capita income through the accumulation of physical capital. However, growth experience has varied widely around the world. The richer countries have a sustained record of growth. Per capita income in the United States has proceeded at an average rate of about 2% per year. While 2% growth may seem small, it is important for students to realize that such growth transforms into a more than doubling of per capita GDP per generation. Unfortunately, the poorer countries have remained poor. Furthermore, their growth rates have not generally matched growth rates in the richer countries, so that the poor countries fall farther and farther behind. Such differences in standards of living and growth prospects present puzzles that the study of economic growth hopes to solve.Classroom Discussion TopicsGetting students to relate to differences in standards of living can sometimes be difficult. It is easy to take one’s own standard of living for granted. An interesting discussion topic is whether students would be willing to travel back in time to 100 or 200 years ago, if they could be one of the richest people of those earlier times. Would the tradeoff be worthwhile? While students typically stress factors like antiquated view about freedom of choice, and racial and gender issues, try to encourage students to divide their concerns into those that are more economic as opposed to social. Also point out that higher standards of living allow societies to be more concerned about issues of equality when mere survival is no longer precarious.Chapter 6 Economic Growth: Malthus and Solow 53Students often view population growth as the result of cultural factors and personal preferences. Against the abundance of daily living, it is easy to forget economic factors. Ask the students for examples ofeconomic factors that might impact on fertility decisions. The Malthusian model suggests that growth may only be achieved through population control. In the modern economy, the costs of raising children can be formidable, and so there is tendency for such costs to be a disincentive to fertility. Such costs may attribute to the tendency for low fertility rates in advanced economies. In more primitive societies, having a large family can be a private form of Social Security. The more children a family has, the more family members there will be to provide for the parents in old age. Poor public health conditions may actually enhance fertility. If each child has a small chance for survival to adulthood, more births are required to produce a given-sized family.OutlineI. Economic Growth FactsA. Pre-1800: Constant Per Capita Income across Time and SpaceB. Post-1800: Sustained Growth in the Rich CountriesC. High I nvestment ↔ High Standard of LivingD. High Population Growth ↔ Low Standard of LivingE. Divergence of Per Capita Incomes: 1800–1950F. No Conditional Convergence amongst All CountriesG. Conditional Convergence amongst the Rich CountriesII. The Malthusian ModelA. Production Determined by Labor and Fixed Land SupplyB. Population Growth and Per Capita ConsumptionC. Steady-state Consumption and Population1. Effects of Technological Change2. Effects of Population ControlD. Malthus: Theory and EvidenceIII. Solow’s Model of Exogenous GrowthA. The Representative ConsumerB. The Representative FirmC. Competitive EquilibriumD. Steady-State Growth1. The Steady-State Path2. Adjustment toward EquilibriumE. Savings and Growth1. Equilibrium Effects2. The Golden Rule: K MP n d =+F. Labor Force Growth and Output Per CapitaG. Total Factor Productivity and Output Per CapitaH. Solow: Theory and Evidence54 Williamson • Macroeconomics, Third EditionIV. Growth AccountingA. Solow ResidualsB. The Productivity Slowdown1. Measurement of Services2. The Relative Price of Energy3. Costs of Adopting New TechnologyC. Cyclical Properties of Solow ResidualsTextbook Question SolutionsQuestions for Review1. In exogenous growth models, growth is caused in the model by forces not explained by the modelitself. Endogenous growth models examine the economic factors that cause growth.2. Pre-1800: Constant Per Capita Income across Time and SpacePost-1800: Sustained Growth in the Rich CountriesHigh Investment ↔ High Standard of LivingHigh Population Growth ↔ Low Standard of LivingDivergence of Per Capita Incomes: 1800–1950No Conditional Convergence amongst All CountriesConditional Convergence amongst the Rich Countries3. An increase in total factor productivity increases the size of the population, but has no effect on theequilibrium level of consumption per capita.4. Only a downward shift in the population growth function can increase the standard of living.5. Malthu’s model is quite successful in explaining economic growth prior to the industrial revolution.Malthu’s model has little relevance for more recent growth experience.6. In the steady state, all variables stay constant: per capita capital, output, consumption, savings. Also,this steady state is stable: whatever the initial capital (except zero), the economy will converge to this steady state.7. With an increase in the saving rate, it becomes possible to sustain a higher level of per capita capital,and thus higher output and consumption. With an increase in the population rate, the contraryhappens, as one needs to provide more newborns with the going per capita capital. A higher total factor productivity improves all per capita variables in the steady state.8. To maximize steady-state per capita consumption, the saving rate must be such that the marginalproduct of capital (the slope of the per capita production function) equals the population growth rate plus the depreciation rate.9. The Malthusian model gave no way out of misery, except for measures that reduce the population.Even technological advances would not raise the standard of living. The Solow model shows that it is possible to obtain a stable standard of living with growing population. And if total factor productivity increases, one can even obtain improvements in the standard of living despite population growth.Chapter 6 Economic Growth: Malthus and Solow 55 10. The Cobb-Douglas production function permits a simple decomposition of economic growth into itscomponent sources.11. In a competitive equilibrium, the parameter a is equal to the share of capital income in total income.12. The Solow residual measures increases in real GDP that are not accounted for by increases in capitaland labor. The Solow residual is highly procyclical as it explains the great majority of the cyclical component in GDP.13. The productivity slowdown could be explained by underestimates of output in the growing servicessector, increases in the relative price of energy, and the costs of adopting new technologies.14. American workers then knew how to incorporate the new technologies, in particular informationtechnology. These efficiency gains may have been realized by 2000, which explains the newslowdown, along with higher energy prices.15. Growth in capital, employment, and total factor productivity account for growth in GDP.16. During this period, growth in these countries was much larger than average. Growth rates for thesecountries were about three times as fast as growth in the United States. However, most of this growth can be attributed to increases in the capital stocks in these countries, and such rapid rates of growth of capital cannot be sustained for long periods of time.Problems1. The amount of land increases, and, at first, the size of the population is unchanged. Therefore,consumption per capita increases. However, the increase in consumption per capita increases the population growth rate, see the figure below. In the steady state, neither *c nor *l are affected by the initial increase in land. This fact can be discerned by noting that there will be no changes in either of the panels of Figure 6.8 in the textbook.56 Williamson • Macroeconomics, Third Edition2. A reduction in the death rate increases the number of survivors from the current period who will stillbe living in the future. Therefore, such a technological change in public health shifts the function ()g cupward. In problem #1 there were no effects on the levels of land per capita and consumption per capita. In this case, the ()g c function in the bottom figure below shifts upward. Equilibriumconsumption per capita decreases. From the top figure below, we also see that the decrease inconsumption per capita requires a reduction in the equilibrium level of land per capita. The size of the population has increased, but the amount of available land is unchanged.Chapter 6 Economic Growth: Malthus and Solow 57 3. For the marginal product of capital to increase at every level of capital, the shift in the productionfunction is equivalent to an increase in total factor productivity.(a) The original and new production functions are depicted in the figures below.(b) Equilibrium in the Solow model is at the intersection of ()n d k+szf k with the line segment ().The old and new equilibria are depicted in the bottom panel of the figure above. The newequilibrium is at a higher level of capital per capita and a higher level of output per capita.(c) For a given savings rate, more effective capital implies more savings, and in the steady state thereis more capital and more output. However, if the increase in the marginal product of capital were local, in the neighborhood of the original equilibrium, there would be no equilibrium effects. A twisting of the production function around its initial point does not alter the intersection point.4. An increase in the depreciation rate acts in much the same way as an increase in the populationgrowth rate. More of current savings is required just to keep the amount of capital per capita constant.In equilibrium output per capita and capital per capita decrease.58 Williamson • Macroeconomics, Third Edition5. A destruction of capital.(a) The long-run equilibrium is not changed by an alteration of the initial conditions. If the economystarted in a steady state, the economy will return to the same steady state. If the economy wereinitially below the steady state, the approach to the steady state will be delayed by the loss ofcapital.(b) Initially, the growth rate of the capital stock will exceed the growth rate of the labor force. Thefaster growth rate in capital continues until the steady state is reached.(c) The rapid growth rates are consistent with the Solow model’s predictions about the likelyadjustment to a loss of capital.6. A reduction in total factor productivity reduces the marginal product of capital. The golden rule levelof capital per capita equates the marginal product of capital with .n d + Therefore, for given ,n d + the golden rule amount of capital per capita must decrease as in the figure below. Therefore the golden rule savings rate must decrease.7. Government spending in the Solow model.(a) By assumption, we know that T = G, and so we may write:()(1)(1)K's Y G d K sY gN d K =−+−=−+−Now divide by N and rearrange as:(1)()(1)k'n szf k sg d k +=−+−Divide by (1 + n ) to obtain:()(1)(1)(1)(1)szf k sg d k k'n n n −=−++++Chapter 6 Economic Growth: Malthus and Solow 59Setting k = k ′, we find that:**()().szf k sg n d k =++This equilibrium condition is depicted in the figure below.(b) The two steady states are also depicted in the figure above.(c) The effects of an increase in g are depicted in the bottom panel of the figure above. Capital percapita declines in the steady state. Steady-state growth rates of aggregate output, aggregate consumption, and investment are all unchanged. The reduction in capital per capita isaccomplished through a temporary reduction in the growth rate of capital.8. The golden rule quantity of capital per capita, *,k is such that *().K MP zf k n d ′==+ A decrease in the population growth rate, n , requires a decrease in the marginal product of capital. Therefore, thegolden rule quantity of capital per capita must increase. The golden rule savings rate may either increase or decrease.60 Williamson • Macroeconomics, Third Edition9. (a) First, we need to determine how bN evolves over time:(bN )′ = (1 + f )(1 + n ) bNThen we just need to redo the analysis of the competitive equilibrium and the steady state as inthe book, replacing every N by bN , every (1 + n ) by (1 + f )(1 + n ), and every n by f + n . The new steady-state per efficiency unit capital is then******()(1)(1)(1)(1)(1)szf k d k k f n f n −=+++++ All aggregate variables then grow at the rate of f + n , while per capita aggregates grow at therate f .(b) An increase in f increases the growth rate of per capita income by the same amount, as f is itsgrowth rate. This happens because the exogenous growth in b raises instant capital and income for everyone without a need to invest in capital.10. Production linear in capital:()()Y K z zf k f k k N N==⇒= (a) Recall Equation (20) from the text, and replace ()f k with k to obtain:+−=+((1))(1)sz d k'k n Also recall that 11 and .Y Y Y'zk k k'N z N z N'=⇒== Therefore: ((1))(1)Y'sz d Y N'n N+−=+ As long as((1))1,(1)sz d n +−>+ per capita income grows indefinitely. (b) The growth rate of income per capita is therefore: ((1))1(1)()(1)Y'Y sz d N'N g Y n Nsz n d n −+−==−+−+=+ Obviously, g is increasing in s .(c) This model allows for the possibility of an ever-increasing amount of capital per capita. In theSolow model, the fact that the marginal product of capital is declining in capital is the key impediment to continual increases in the amount of capital per capita.Chapter 6 Economic Growth: Malthus and Solow 6111. Solow residual calculations.(a) To calculate the Solow residuals, we apply the formula, 0.360.64ˆˆˆˆ/,zY K N = to the values in the provided table. Adding a new column for these values, we obtain:Year ˆY ˆK ˆN ˆz 1995 8031.7 25487.3 124.9 9.4781996 8328.9 26222.3 126.7 9.6401997 8703.5 27018.1 129.6 9.8231998 9066.9 27915.9 131.5 10.0191999 9470.3 28899.9 133.5 10.2362000 9817.0 29917.1 136.9 10.3122001 9890.7 30793.4 136.9 10.2822002 10048.8 31599.6 136.5 10.3692003 10301.0 32426.2 137.7 10.4722004 10703.5 33304.9 139.2 10.7032005 11048.6 34191.7 141.7 10.820(b) Next, we compute the percentage changes in each of the table entries. These values arepresented in the table below.Year ˆˆY Y Δ/ (%) ˆˆK K Δ/ (%) ˆˆN N Δ/ (%) ˆˆzz Δ/ (%) 1996 3.70 2.88 1.44 1.71 1997 4.50 3.03 2.29 1.901998 4.18 3.32 1.47 2.001999 4.45 3.52 1.52 2.172000 3.66 3.52 2.55 0.742001 0.75 2.93 0.00 −0.292002 1.60 2.62 −0.29 0.852003 2.51 2.62 0.88 0.992004 3.91 2.71 1.09 2.212005 3.22 2.66 1.80 1.0962 Williamson • Macroeconomics, Third EditionTo compare the contributions to growth, we need to compare the magnitudes,ˆˆˆˆ0.36(/),0.64(/),KKNN ΔΔ and ˆˆ/.z z Δ These values are presented in the table below.Year ˆˆ0.36(Δ/K K) (%) ˆˆ0.64(Δ/N N)(%) ˆˆz z Δ/ (%)1996 1.04 0.92 1.711997 1.09 1.46 1.901998 1.20 0.94 2.001999 1.27 0.97 2.172000 1.27 1.63 0.742001 1.05 0.00 −0.292002 0.94 −0.19 0.852003 0.94 0.56 0.992004 0.98 0.70 2.212005 0.96 1.15 1.09Most often, when output is growing, the biggest contribution to growth comes from increases intotal factor productivity. In 1991 and in 2001, both bad years for growth, total factor productivity decreased. In the other years, growth in total factor productivity is usually the largest contributor to growth, while increases in capital and labor equally share the role of the leading cause of growth in the other years. In the later years, capital growth has come to be relatively more important than in the early years.。

第11章市场出清的经济周期模型11.1 复习笔记一、经济周期理论概述1．经济周期理论的发展进程（1）凯恩斯的经济周期模型货币在短期不是中性的，这种非中性是由工资和价格的短期刚性引起的。

在凯恩斯模型中，价格和工资刚性以及由此造成的所有市场可能无法在每一时点上出清，是经济冲击造成总产出波动的形成机制的关键所在。

价格和工资缓慢向出清的市场变动的事实，意味着货币政策和财政政策在应对总冲击时可以发挥稳定经济的作用。

（2）货币主义的经济周期模型货币主义者往往认为，货币政策是比财政政策更有效的稳定工具，但他们对政府政策微调经济的能力持怀疑态度。

一些货币主义者认为，在短期，政策可能是有效的，但非常短。

（3）理性预期学派的经济周期模型理性预期革命提出的两大原则是：①宏观经济学模型应建立在微观经济学原理的基础上，即这些模型应以对消费者和企业的偏好、禀赋、技术和最优行为的描述为后盾；②均衡模型是研究宏观经济现象的最有成效的工具。

2．分析不同经济周期理论的必要性（1）财政政策和货币政策的决策者能够通过经济周期理论，了解左右经济的宏观经济冲击是什么，它对未来总体经济活动有什么影响。

（2）每一种经济周期模型都能确定经济的一个或几个特征及经济对宏观经济冲击作出反应的一些方面。

如果将所有这些特征纳入一个模型中，将无助于认识经济周期表现的基本规律和政府政策。

二、真实经济周期模型真实经济周期模型由芬恩·基德兰德和爱德华·普雷斯科特于20世纪80年代初首创。

1．全要素生产率持久提高的均衡效应假定货币跨期模型中的全要素生产率是持久提高，即z和z＇分别提高。

（1）全要素生产率z提高的影响①当期z提高会增加每一数量劳动投入的边际劳动产出，劳动需求曲线右移，从而导致产出供给曲线右移。

如图11-1所示。

图11-1 真实经济周期模型中全要素生产率持久提高的影响②预期未来全要素生产率z＇提高的影响：a ．投资品需求会增加，因为典型企业预期未来边际资本产出会增加；b ．典型消费者预期较高的未来全要素生产率会带来较高的未来收入，因此一生财富增加，消费品需求增加。