国际经济学ch-04

nullChapter 3Chapter 3Specific Factors and Income DistributionChapter OrganizationChapter OrganizationIntroduction The Specific Factors Model International Trade in the Specific Factors Model Income Distribution and the Gains from Trade The Political Economy of Trade: A Preliminary View Summary Appendix: Further Details on Specific FactorsIntroductionIntroductionTrade has substantial effects on the income distribution within each trading nation. There are two main reasons why international trade has strong effects on the distribution of income: Resources cannot move immediately or costlessly from one industry to another. Industries differ in the factors of production they demand. The specific factors model allows trade to affect income distribution.The Specific Factors ModelThe Specific Factors ModelAssumptions of the Model Assume that we are dealing with one economy that can produce two goods, manufactures and food. There are three factors of production; labor (L), capital (K) and land (T for terrain). Manufactures are produced using capital and labor (but not land). Food is produced using land and labor (but not capital). Labor is therefore a mobile factor that can be used in either sector. Land and capital are both specific factors that can be used only in the production of one good. Perfect Competition prevails in all markets. The Specific Factors ModelThe Specific Factors ModelHow much of each good does the economy produce? The economy’s output of manufactures depends on how much capital and labor are used in that sector. This relationship is summarized by a production function. The production function for good X gives the maximum quantities of good X that a firm can produce with various amounts of factor inputs. For instance, the production function for manufactures (food) tells us the quantity of manufactures (food) that can be produced given any input of labor and capital (land). The Specific Factors ModelThe Specific Factors ModelThe production function for manufactures is given by QM = QM (K, LM) (3-1) where: QM is the economy’s output of manufactures K is the economy’s capital stock LM is the labor force employed in manufactures The production function for food is given by QF = QF (T, LF) (3-2) where: QF is the economy’s output of food T is the economy’s supply of land LF is the labor force employed in foodThe Specific Factors ModelThe Specific Factors ModelThe full employment of labor condition requires that the economy-wide supply of labor must equal the labor employed in food plus the labor employed in manufactures: LM + LF = L (3-3) We can use these equations and derive the production possibilities frontier of the economy.The Specific Factors ModelThe Specific Factors ModelProduction Possibilities To analyze the economy’s production possibilities, we need only to ask how the economy’s mix of output changes as labor is shifted from one sector to the other. Figure 3-1 illustrates the production function for manufactures. The Specific Factors ModelThe Specific Factors ModelFigure 3-1: The Production Function for ManufacturesThe Specific Factors ModelThe Specific Factors ModelThe shape of the production function reflects the law of diminishing marginal returns. Adding one worker to the production process (without increasing the amount of capital) means that each worker has less capital to work with. Therefore, each additional unit of labor will add less to the production of output than the last. Figure 3-2 shows the marginal product of labor, which is the increase in output that corresponds to an extra unit of labor.The Specific Factors ModelThe Specific Factors ModelFigure 3-2: The Marginal Product of LaborThe Specific Factors ModelThe Specific Factors ModelEconomy’s production possibility frontier (PP)Production function for manufacturesEconomy’s allocation of labor (AA)Production function for foodFigure 3-3: The Production Possibility Frontier in the Specific Factors Model边际报酬递减是特定要素模型和李嘉图模型的关键区别The Specific Factors ModelThe Specific Factors ModelPrices, Wages, and Labor Allocation How much labor will be employed in each sector? To answer the above question we need to look at supply and demand in the labor market. Demand for labor: In each sector, profit-maximizing employers will demand labor up to the point where the value produced by an additional person-hour equals the cost of employing that hour. The Specific Factors ModelThe Specific Factors ModelThe demand curve for labor in the manufacturing sector can be written: MPLM x PM = w (3-4) The wage equals the value of the marginal product of labor in manufacturing. The demand curve for labor in the food sector can be written: MPLF x PF = w (3-5) The wage rate equals the value of the marginal product of labor in food.The Specific Factors ModelThe Specific Factors ModelThe wage rate must be the same in both sectors, because of the assumption that labor is freely mobile between sectors. The wage rate is determined by the requirement that total labor demand equal total labor supply: LM + LF = L (3-6) The Specific Factors ModelThe Specific Factors ModelFigure 3-4: The Allocation of LaborThe Specific Factors ModelThe Specific Factors ModelAt the production point the production possibility frontier must be tangent to a line whose slope is minus the price of manufactures divided by that of food. Relationship between relative prices and output: -MPLF/MPLM = -PM/PF (3-7) The Specific Factors ModelThe Specific Factors ModelSlope = -(PM /PF)1Figure 3-5: Production in the Specific Factors ModelThe Specific Factors ModelThe Specific Factors ModelWhat happens to the allocation of labor and the distribution of income when the prices of food and manufactures change? Two cases: An equal proportional change in prices A change in relative pricesThe Specific Factors ModelThe Specific Factors ModelPF increases 10%10% wage increasePM increases 10%Figure 3-6: An Equal Proportional Increase in the Prices of Manufactures and FoodThe Specific Factors ModelThe Specific Factors ModelWhen both prices change in the same proportion, no real changes occur. The wage rate (w) rises in the same proportion as the prices, so real wages (i.e. the ratios of the wage rate to the prices of goods) are unaffected. The real incomes of capital owners and landowners also remain the same.The Specific Factors ModelThe Specific Factors ModelWhen only PM rises, labor shifts from the food sector to the manufacturing sector and the output of manufactures rises while that of food falls. The wage rate (w) does not rise as much as PM since manufacturing employment increases and thus the marginal product of labor in that sector falls.The Specific Factors ModelThe Specific Factors Model7% upward shift in labor demandFigure 3-7: A Rise in the Price of ManufacturesThe Specific Factors ModelThe Specific Factors ModelSlope = - (PM /PF)1Slope = - (PM /PF) 2Figure 3-8: The Response of Output to a Change in the Relative Price of ManufacturesThe Specific Factors ModelThe Specific Factors ModelFigure 3-9: Determination of Relative PricesThe Specific Factors ModelThe Specific Factors ModelRelative Prices and the Distribution of Income Suppose that PM increases by 10%. Then, we would expect the wage to rise by less than 10%, say by 5%. What is the economic effect of this price increase on the incomes of the following three groups? Workers Owners of capital Owners of landThe Specific Factors ModelThe Specific Factors ModelWorkers: We cannot say whether workers are better or worse off; this depends on the relative importance of manufactures and food in workers’ consumption. Owners of capital: They are definitely better off. Landowners: They are definitely worse off. nullAssumptions of the model Assume that both countries (Japan and America) have the same relative demand curve. Therefore, the only source of international trade is the differences in relative supply. The relative supply might differ because the countries could differ in: Technology Factors of production (capital, land, labor) International Trade in the Specific Factors ModelnullResources and Relative Supply What are the effects of an increase in the supply of capital stock on the outputs of manufactures and food? A country with a lot of capital and not much land will tend to produce a high ratio of manufactures to food at any given prices. International Trade in the Specific Factors ModelnullIncrease in capital stock, KInternational Trade in the Specific Factors ModelFigure 3-10: Changing the Capital StocknullAn increase in the supply of capital would shift the relative supply curve to the right. An increase in the supply of land would shift the relative supply curve to the left. What about the effect of an increase in the labor force? The effect on relative output is ambiguous, although both outputs increase.International Trade in the Specific Factors ModelnullTrade and Relative Prices Suppose that Japan has more capital per worker than America, while America has more land per worker than Japan. As a result, the pretrade relative price of manufactures in Japan is lower than the pretrade relative price in America. International trade leads to a convergence of relative prices. International Trade in the Specific Factors ModelnullInternational Trade in the Specific Factors ModelFigure 3-11: Trade and Relative PricesnullThe Pattern of Trade In a country that cannot trade, the output of a good must equal its consumption. International trade makes it possible for the mix of manufactures and food consumed to differ from the mix produced. A country cannot spend more than it earns. International Trade in the Specific Factors ModelnullBudget constraint (slope = -PM/PF)International Trade in the Specific Factors ModelFigure 3-12: The Budget Constraint for a Trading EconomynullQJFQAFDAFDJFJapanese budget constraintAmerican budget constraintInternational Trade in the Specific Factors ModelFigure 3-13: Trading EquilibriumIncome Distribution and the Gains from TradeIncome Distribution and the Gains from TradeTo assess the effects of trade on particular groups, the key point is that international trade shifts the relative price of manufactures and food. Trade benefits the factor that is specific to the export sector of each country, but hurts the factor that is specific to the import-competing sectors. Trade has ambiguous effects on mobile factors.Income Distribution and the Gains from TradeIncome Distribution and the Gains from TradeCould those who gain from trade compensate those who lose, and still be better off themselves? If so, then trade is potentially a source of gain to everyone. The fundamental reason why trade potentially benefits a country is that it expands the economy’s choices. This expansion of choice means that it is always possible to redistribute income in such a way that everyone gains from trade.Income Distribution and the Gains from TradeIncome Distribution and the Gains from TradeFigure 3-14: Trade Expands the Economy’s Consumption PossibilitiesThe Political Economy of Trade: A Preliminary ViewThe Political Economy of Trade: A Preliminary ViewTrade often produces losers as well as winners. Optimal Trade Policy The government must somehow weigh one person’s gain against another person’s loss. Some groups need special treatment because they are already relatively poor (e.g., shoe and garment workers in the United States). Most economists remain strongly in favor of more or less free trade. Any realistic understanding of how trade policy is determined must look at the actual motivations of policy.The Political Economy of Trade: A Preliminary ViewThe Political Economy of Trade: A Preliminary ViewIncome Distribution and Trade Politics Those who gain from trade are a much less concentrated, informed, and organized group than those who lose. Example: Consumers and producers in the U.S. sugar industry SummarySummaryInternational trade often has strong effects on the distribution of income within countries, so that it often produces losers as well as winners. Income distribution effects arise for two reasons: Factors of production cannot move instantaneously and costlessly from one industry to another. Changes in an economy’s output mix have differential effects on the demand for different factors of production.SummarySummaryA useful model of income distribution effects of international trade is the specific-factors model. In this model, differences in resources can cause countries to have different relative supply curves, and thus cause international trade. In the specific factors model, factors specific to export sectors in each country gain from trade, while factors specific to import-competing sectors lose. Mobile factors that can work in either sector may either gain or lose.SummarySummaryTrade nonetheless produces overall gains in the sense that those who gain could in principle compensate those who lose while still remaining better off than before.Appendix: Further Details on Specific FactorsAppendix: Further Details on Specific FactorsFigure 3A-1: Showing that Output Is Equal to the Area Under the Marginal Product CurveAppendix: Further Details on Specific FactorsAppendix: Further Details on Specific FactorsWagesw/PMFigure 3A-2: The Distribution of Income Within the Manufacturing SectorAppendix: Further Details on Specific FactorsAppendix: Further Details on Specific Factors(w/PM)1 (w/PM)2Figure 3A-3: A Rise in PM Benefits the Owners of CapitalAppendix: Further Details on Specific FactorsAppendix: Further Details on Specific Factors(w/PF)2 (w/PF)1Figure 3A-4: A Rise in PM Hurts Landowners