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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.。
威廉森《宏观经济学》（第3版）模拟试题及详解（一）一、名词解释（每小题5分，共计20分）1．IS LM-模型答：IS LM-模型是由英国经济学家希克斯和美国经济学家汉森在凯恩斯宏观经济理论基础上概括出的一个经济分析模式，即“希克斯—汉森模型”，也称“希克斯—汉森综合”或“希克斯—汉森图形”。
IS LM-模型是宏观经济分析的一个重要工具，是描述产品市场和货币市场之间相互联系的理论结构。
在产品市场上，国民收入取决于消费、投资、政府支出和净出口加起来的总支出或者说总需求水平，而总需求尤其是投资需求要受到利率影响，利率则由货币市场供求情况决定，就是说，货币市场要影响产品市场；另一方面，产品市场上所决定的国民收入又会影响货币需求，从而影响利率，这又是产品市场对货币市场的影响。
可见，产品市场和货币市场是相互联系、相互作用的，而收入和利率也只有在这种相互联系、相互作用中才能决定。
IS曲线是描述产品市场达到均衡，即I S=时，国民收入与利率之间存在着反向变动关=时，国民收入和利率之间存在着同系的曲线。
LM曲线是描述货币市场达到均衡，即L M向变动关系的曲线。
把IS曲线和LM曲线放在同一个图上，就可以得出说明两个市场同时均衡时，国民收入与利率决定的IS LM-模型。
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一般通过支出法和收入法两种方法进行核算。
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。
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。
第七单元经济周期理论本单元所涉及到的主要知识点：1．经济周期的含义、阶段与种类； 2．经济周期的原因；3．卡尔多经济周期模型； 4．乘数－加速数模型一、单项选择1．经济周期中的两个主要阶段是（）。
a．繁荣和萧条； b．繁荣和衰退； c．萧条和复苏； d．繁荣和复苏。
2．下列对经济周期阶段排序正确的是（）。
a．复苏，繁荣，衰退，萧条； b．复苏，繁荣，萧条，衰退；c．复苏，萧条，衰退，繁荣； d．复苏，衰退，萧条，繁荣。
3．由于经济衰退而形成的失业属于：（）。
a．摩擦性失业； b．结构性失业；c．周期性失业； d．自然失业。
4．下列哪种说法表达了加速原理（）。
a．消费支出随着投资支出增长率的变化而变化；b．投资支出随着国民收入增量的变化而变化；c．国民收入随着投资支出的变化而变化；d．投资支出的减少会造成消费支出一轮一轮地减少。
5．下列哪种说法没有表达加速原理（）。
a．国民收入增长率的变化将导致投资支出的变化；b．消费支出的变化会引起投资支出更大的变化；c．投资支出的减少会造成消费支出一轮一轮地减少；d．投资支出随着国民收入增量的变化而变化。
6．加速原理发生作用的条件是（）。
a．投资的增加会导致国民收入增加；b．消费品的生产需要有一定数量的资本品，因而消费支出的增加会导致投资支出的增加；c．投资的增加会导致消费支出的持续增加；d．投资支出的减少会造成消费支出地减少。
7．经验统计资料表明，在经济周期里，波动最大的一般是（）。
a．资本品的生产； b．农产品的生产； c．日用消费品的生产； d．a和c。
8．所谓资本形成是指（）。
a．净投资； b．总投资； c．更新投资； d．存货的投资。
9．假定某经济连续两年的国民收入都是1200亿美元，在资本－产量比率等于2的条件下，净投资等于（）。
a．1200亿美元； b．2400亿美元； c．2000亿美元； d．0。
10．已知某经济某一年的国民收入是1000亿美元，净投资为零；第二年国民收入增至1200亿美元。
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3章经济周期的衡量一、复习题1．经济周期的主要明显特征是什么？答：经济周期的明显特征是：经济周期围绕着实际GDP的趋势波动。
用与现实的实际GDP非常吻合的平滑曲线来表示实际GDP的趋势，这种趋势意味着部分实际GDP可归因于长期增长因素。
其余未分析的，即对趋势的偏离，则用经济周期活动来表示。
表示实际GDP的增长趋势的曲线绕着趋势上下变动，波谷是对趋势的最大负偏离，波峰是对趋势的最大正偏离，从而形成衰退与繁荣的经济周期波动。
2．除持续性外，偏离GDP趋势的三个重要特征是什么？答：偏离GDP趋势的三个重要特征是：（1）偏离实际GDP趋势的时间序列很不稳定。
（2）实际GDP围绕趋势波动的幅度没有规律性。
一些波峰和波谷意味着对趋势的巨大偏离，而另一些波峰和波谷则意味着对趋势的小幅偏离。
（3）实际GDP围绕趋势波动的频率没有规律性。
实际GDP中波峰和波谷之间的时间跨度变化很大。
3．解释预测长期GDP为何困难。
答：预测长期GDP困难的原因：（1）实际GDP围绕趋势波动的幅度没有规律性，一些波峰和波谷意味着对趋势的巨大偏离，而另一些波峰和波谷则意味着对趋势的小幅偏离。
（2）实际GDP围绕趋势波动的频率没有规律性。
实际GDP中波峰和波谷之间的时间跨度变化很大。
（3）偏离实际GDP趋势的时间序列很不稳定。
总之，实际GDP波动的不稳定使这些波动难以预测，而且不稳定性也使得转折点何时发生难以预测，而波幅和频率的无规律则意味着难以预测衰退和繁荣的强度和时间长短。
4．总体经济活动变量的联动为何重要？答：尽管实际GDP波动具有不规律的形式，但宏观经济诸变量一起波动的格局显示出了较强的规律性，这些波动格局称为联动。
通过以时间序列图或散点图的形式为两个经济变量偏离其趋势的百分比作图，或通过计算偏离趋势的百分比标准差，就可判别联动。
联动性很重要，因为联动性的规律表明，经济周期是大同小异的。
经济周期的这一性质可能产生分析经济周期的一般理论，这一可能的新理论不同于以往的理论，即：将每一个经济周期都看作是一系列独特条件的结果再进行经济周期的研究。
宏观经济学-课后思考题答案_史蒂芬威廉森010Chapter 10A Monetary Intertemporal Model: Money, Prices,and Monetary PolicyTeaching GoalsAnalysis of a monetary economy can become quite complex. Modern economies require significant specialization to function well. Such specialization requires a commonly accepted medium of exchange. Money serves this function. Although it matters quite a lot that we have money, the actual quantity of money in circulation is not very important. This fact emerges because the quantity of money is neutral, if not in the very short run, certainly in the long run.In the monetary intertemporal model, changes in the money supply affect the level of prices, but do not otherwise affect economic outcomes; money is neutral. Real factors may also affect the price level. The price level adjusts to keep money demand and money equal. Disturbances that change the equilibrium levels of output and the real interest rate therefore change the price level. Shifts in preferences for money holding also affect the price level.The principle role of monetary policy in the monetary intertemporal model is to control the level of prices.A popular goal of policy is to stabilize the price level in response to shocks to the economy. However, the central bank’s ability to stabilize prices may be compromised if money demand does not behave in a predictable manner. It is also important for policy to set targets and adhere to particular policy rules.Classroom Discussion TopicsThe payments technology has continually advanced over time, but the rate of advance has acceleratedin the era of computer technology. Ask the students for examples of advances in this technology beyond the routine use of cash and the writing of paper checks. Some obvious possibilities include the use of ATMs, computer and telephone banking, the use of prepaid phone cards and other forms of smartcard technologies. Students are also likely to discuss the existence of credit cards and the ever more sophisticated ways to use credit cards and protect against fraud. As one example, there is the use of credit cards to pay for purchases over the Internet. In discussing these possibilities, it is also important to distinguish the payments technology from the proper measurement of the money supply. For example, it is important to distinguish between payment arrangements that are uses of credit, like the use of credit cards, from uses of money, like cash and transaction deposits.Standard macroeconomic analysis, like that of this chapter, emphasizes central banks’ control of the quantity of money in circulation. However, most contemporary discussions of U.S. monetary policy focus on the Federal Reserve’s control of “interest rates.” This chapter offers plenty of opportunities to discuss real life events. For example, discuss the upcoming meeting of the FOMC, what it decides on, what information it uses, and what it may do.102 Williamson ? Macroeconomics, Third EditionIn the monetary intertemporal model, the real interest rate is market determined and cannot be influenced by central bank behavior. Ask the students whether they believe a simplistic view of popular press coverage that seems to refute the notion that the interest rate is market determined. Note the importance of the distinction between the federal funds rate and the sort of real interest rates that motivate saving and investment choices. Is it possible that the Fed adjusts the federal funds rate to more closely resemble other market interest rates? Is it possible to control the nominal interest rate while being unable to influence the real interest rate? Even if the Fed is able to control one very narrowly defined real interest rate, does this mean that models like those in this chapter are not useful descriptions of reality?OutlineI. Functions of MoneyA. Medium of ExchangeB. Store of ValueC. Unit of AccountII. Measuring the Money SupplyA. The Monetary Base1. Currency Outside the Fed2. Depository Institution Deposits at the FedB. M11. Currency Held by the Public2. Traveler’s Checks3. Demand Deposits4. Other Checkable DepositsC. M21. Savings Deposits2. Small-Denomination Time Deposits3. Retail Money Market Mutual FundsD. M31. Large-Denomination Time Deposits2. Institutional Money Market Mutual Funds3. Repurchase Agreements4. EurodollarsIII. Introduction to the Monetary Intertemporal ModelA. The Need for Money1. Single Coincidence of Wants2. Double Coincidence of Wants3. The Cash-in-Advance ModelB. Real and Nominal Interest Rates1. Nominal Bonds2. The Nominal Interest Rate3. The Fisher RelationshipChapter 10 A Monetary Intertemporal Model: Money, Prices, and Monetary Policy 103C. Representative Consumer1. The Cash-in-Advance Constraint2. Banking Service Cost Function3. Optimal Choice of Banking ServicesD. Representative Firm1. The Cash-in-Advance Constraint2. Banking Service Cost Function3. Optimal Choice of Banking Services E. Money and the Government Budget ConstraintIV. Competitive Equilibrium in the Monetary Intertemporal ModelA. Graphical ApparatusB. A Change in the Level of the Money Supply1. Sources of Changes in the Money Supply a. Helicopter Drops: Taxes/Transfersb. Open-Market Operationsc. Seigniorage2. Classical Dichotomy3. Neutrality of MoneyC. A Change in Current Total Factor Productivity1. Real Effects2. Price-Level EffectsD. Shifts in Money Demand1. Sourcesa. Information Technology and Banking Costsb. New Financial Instrumentsc. Government Regulationsd. Perceived Riskiness of Bankse. Changes in Circumstances in the Banking System2. Neutrality vis-à-vis Real Variables3. Price-L evel EffectsE. Monetary Policy Rules1. Under Perfect Information2. Money Supply Targeting3. Nominal Interest Rate Targeting4. The Taylor RuleTextbook Question SolutionsQuestions for Review1. Money serves as a medium of exchange, a store of value, and a unit of account.2. Measures of the money supply include M 0, M 1, and M 2. The monetary base, M 0, includes all currency outside of currency held by the Federal Reserve, and deposits of depositary institutions at the FederalReserve. M 1 includes all currency held by the public (as opposed to bank vaults, the Fed, and the U.S. Treasury), plus travelers’ checks, demand deposits, and other checkable deposits. M 2 includes all of M 1 plus savings deposits, small-denomination time deposits, and retail money market mutual funds.104 Williamson ? Macroeconomics, Third Edition3. Use of money, as opposed to barter in goods or credit, solves the problem of the double coincidenceof wants.4. The nominal rate of interest is approximately equal to the real rate of interest plus the rate of inflation. The exact relationship is:(1)1(1)R r i ++=+ 5. The real rate of return on money is approximately equal to minus the rate of inflation. If we define thereal rate of return on money as ,m r then the exact relationship is:11(1)m r i +=+ 6. The demand for money stems from the desire of consumers to hold money to make purchases. Thosecan be made with a debit card as well, but this is costly, so the consumer decides in advance how much money to withdraw from the bank account. In addition, firms demand money in a similar way so that they can purchase investment goods.7. A permanent, once-and-for-all increase in the money supply has no effect on the real economy. Thatis, money is neutral. The only effect of the increase in the money supply is a permanent, proportionate increase in the price level.8. The government can change the money supply through a temporary tax cut (a helicopter drop), anopen-market operation, and seigniorage.9. The steady-state effects of an increase in the money growth rate include an increase in the rate ofinflation, a reduction in output, a reduction in employment, an increase in the real wage, and anincrease in the nominal interest rate.10. A change in the cost of banking services alters the trade-off between withdrawing money inadvance for purchases and using the debit card. For example, if the cost decreases, thenconsumers and firms will use debit cards more and will withdraw less cash, thus reducing thedemand for money.11. Money demand can increase if incomes rise (households then want to consume more and thus needmore cash, firms want to buy more investment goods and also need more cash), if the nominalinterest rate is lower, as then the opportunity cost of holding money is lower, and if prices are higher, as money demand is formulated in nominal terms. Money demand can be shifted by anything that would alter the cost of banking services, such as: new information technologies that lower the cost of accessing bank accounts, new financial instruments that lower the cost of banking, changes in bank regulation, changes in the perceived risk of banks, and changes in various circumstances in thebanking system.12. As money is neutral in this model, there is no real goal of any relevance, only a nominal goal. Thiswould be to keep inflation low in order to achieve nominal interest rates as low as possible to prevent households and firms to be constrained by the cash-in-advance constraint.13. A monetary policy rule establishes the money supply as a function of observable aggregates. Threeexamples are money supply targeting, nominal interest rate targeting, and the Taylor rule.Chapter 10 A Monetary Intertemporal Model: Money, Prices, and Monetary Policy 105 14. Money supply targeting implies no change of money supply in response to any of the three shifts,leading to price changes and the failure of the price stability goal. Nominal interest rate targeting achieves price stability in response to money demand shocks, but not to output demand or supply shocks. The Taylor Rule has ambiguous consequences with the model we have studied so far. Problems1. Bank service function with fixed cost.(a) This fix cost can be interpreted as the cost of obtaining a debit card, which is independent of thecost of using it.(b) None, as HXis unaffected.(c) It will change the level of money demand, but it has no impact on the slope of money demand oron its shifts in reaction to various circumstances. Indeed, the slope of H(X), or J(R), is still thesame.(d) With a higher D, households make the same choice of banking services, as X must be such thatHX = R, and HXhas not changed. The same applies to the firm. Thus, there is change to thedemand for money and no change to the price level.2. Zero nominal interest rate.(a) Now HX=0, which can only be achieved at X =0.(b) None. Banks are not used at all.(c) Household and firms have no reason to hold any bonds, as their return is the same as money andit costs to use the debit card. So everything is done with cash, and economic agents are notconstrained by the cash-in-advance constraint anymore. However, in order to achieve a zeronominal interest rate, it implies that the inflation rate should be the opposite of the real interestrate, that is negative. This happens only rarely.3. Government spending in the monetary intertemporal model.(a) The real effects of a temporary increase in government spending are the same as those in the realintertemporal model. Output and employment increase, the real interest rate increases, and thereal wage decreases. The new consideration is the effect on the price level. The increase inincome causes money demand to increase. The increase in the real interest rate causes thedemand for money to decrease. With a fixed supply of money, the price level must change tokeep money supply and money demand equal. If the income effect on money demand is stronger, then prices must decrease. If the interest rate effect on money demand is stronger, then pricesmust increase.(b) The real effects of a permanent increase in government spending are the same as those in the realintertemporal model. Output and employment increase, the real interest rate decreases, and thereal wage decreases. In this case the effects of the increase in income and the decrease in theinterest rate both work to increase money demand. In this case, the price level unambiguouslydeclines.4. The real effects of a decrease in the capital stock are the same as those in the real intertemporalmodel. The decrease in K leads to an increase in the real interest rate and a decrease in the real wage.The effects on output and employment are uncertain, although it may be somewhat more likely that output will decrease. A decrease in output along with an increase in the real interest rate both work to decrease money demand. Therefore, the price level would need to increase to keep money supply and money demand equal.5. The current-period real effects of the future increase in total factor productivity are the same as thosepredicted by the real intertemporal model. Output and employment increase, the real wage decreases, and the real interest rate increases. The increase in output increases money demand and the current price level increases.106 Williamson ? Macroeconomics, Third Edition6. The increased presence of ATMs would allow consumers to get by holding less money. Therefore,this disturbance shifts the money demand curve to the left, so the price level would increase to keep money demand and money supply equal.7. Implementing a nominal interest rate rule.(a) This increase in housing construction may arise from household confidence, for example afteran increase in the stock price. Thus we have a temporary increase in money demand with areduction in prices. To lower the nominal interest rate, the monetary authority increases themoney supply, which raises prices to the previous level. Price stabilization is successful.(b) This is like a drop in current total factor productivity with no consequence for future total factorproductivity. Thus, we have a shift to the left of output supply, reducing output and increasingthe real interest rate. Money demand thus drops and prices increase. The monetary authorityshould react by increasing the money supply to reduce the nominal interest rate to the target, but this increases prices further. Prices are then not stable as intended.(c) We learn that total factor productivity is up, and permanently so. This implies that both outputdemand and supply increase, the real interest rate drops, and that money demand shifts to theright leading to lower prices. Under a nominal interest rate target rule, the monetary authoritywould increase the nominal interest rate by reducing the money supply, thus further reducingprices. Prices are then not stable as intended.8. Textbook Chapter 9 discusses the likely effects of a permanent increase in government spending inthe real intertemporal model. As depicted in textbook Figure 9.18, a permanent increase ingovernment spending increases output. This effect works in the direction of increasing the demand for money. In the figure below, the initial price level is P*. With the money supply fixed at M, the price level decreases to ?.P To keep the price level at P*, the money supply must increase to .M If the central bank were pursuing a policy of price-level stabilization, the central bank would find it useful to be able to accurately predict the advent of this disturbance.。
