国际贸易国贸课第1章

1、CHAPTER 1比较优势理论THEORY OF COMPARATIVE ADVANTAGEKEY WORDS:Mercantilism重商主义absolute advantage绝对优势classic theory spelization古典理论专业化假定amptioncomparative advantage比较优势price ratios equilibrium价格比率均衡opportunity cost机会成本productionsibilities curve 生产可能性曲线marginal rate of substitution边际替代率slope斜率to be tangent切

2、线, 正切increasing opportunity cost 机会成本递增demand preference需求偏好indifference curve无差异曲线1.41.5roductionThe Mercantilists Views on TradeTrade Based on Absolute Advantage: Adam Smith Trade Bases on Comparative Advantage: David Ricardo Ricardos Constant Opportunity Costs AndThe Production-sibilitie

3、s Curve1.6Increasing Opportunity Costs AndThe Production-sibilities Curve一.二.三.四.国际贸易理论的分析思路重商主义理论.的绝对优势理论的比较优势理论五.六.机会成本不变条件下的贸易利益机会成本递增条件下的贸易利益一.国际贸易理论的分析思路国际贸易理论包括两个基本部分：国际贸易产生的原因和结果。或者：国际贸易利益是如何产生的，又是如何分配的。We can easily find of the same products bett the main cause of IT is the price difference

4、n two countries. It is profitable.两个国家生产同样产品存在价格差异。国际贸易理论就是价格差异产生的原因，供求分析是基本方法。From the poof supply, the price difference isresulted from thedifferent opportunity costs.Productive technology Factor endowment Economies of scale costs priFrom the poof demand, the price differencedepends on bothdemand

5、preference ande.二. The Mercantilists Views on Trade重商主义理论（观点）三.的绝对优势理论Trade Based on Absolute Advantage: Adam SmithIn his Wealth of Nations (1776), he said:It isof every prudent master of a family, never to attemptto make at home what it will cost him more to maken to buy. Thetailor does notempt to

6、make his own shoes, but buy them from theshoemaker.What is prudencehe conduct of every private family, can scarcebe follyhat of a great kingdom. If a foreign country can supply uswicommodity chern we ourselves can make it, better buy itof them with some part of the product of our own industry, emplo

7、yedin a way in which wee some advantage.“每一个精明的家长都会遵循以下准则：从不在家里生产那些比还贵的产品。裁缝不会试图自己做鞋，而是从鞋匠哪里买鞋在每一个私人家庭的行为中是精明的事，在一个大国的行为中不大会是荒唐的。如果外国能以比自己制造还便宜的商品供应，那么，最好就用。”具有某些优势的行业中生产出来的部分产品来向他们The law of absolute advantage: absolute advantage comes from theabsolute difference of productivities based on the abso

8、lute difference of technologies. A nation should produce and export the commodities ofabsoluteadvantage,andimportthecommoditiesofabsolutedisadvantage.“绝对优势”理论（原因和结论）：各国间存在的生产技术上的差别，以及由此造成的劳动生产率和生产成本的绝对差别，是国际分工和国际贸易的基础。各国应集中生产并出口具有“绝对优势”的产品，进口其不具有“绝对优势”的产品，其结果比自己什么都生产更有利。下面分析“绝对优势”是如何产生的：How to deter

9、mine the absolute advantage in productive technology? The direct way is “productivity”.在劳动是唯一投入的情况下，生产技术的优劣可以用劳动生产率来衡量。The A.A theory is based on the following amptions:1.There are two nations (Nation 1 and Nation 2), two commodities(commodity X and commodity Y).2.3.4.Lathe only input.Nations use th

10、e different technology in production.Both commodities are produced under constant returns to scale in both nations.Tastes are equal in both nations.There is perfect competition in both commodities in both nations.5.6.7.There is perfect mobility within each nation but nofactor mobility.ernational8.Th

11、ere are no transporion costs, tariffs, or other obstructions tothe free flow ofernational trade.9.All resourare fully employed in both nations.10.ernational trade betn the two nations is balanced.Table1-1Case of Absolute Advantagehe U.S.In China11小麦布2 hours4 hours2.5 hours 1 hours在封济中，价格是两种商品的比价。Tab

12、le 1-2he U.S.In ChinaWithout Trade Price of wheat Price of cloth0.5 布/1 麦2.0 麦/1 布2.5 布/1 麦0.4 麦/1 布商人在国内以 0.5 的布换得的小麦到中国换的了一个的同成类产品，2.5 布，然后把布运回本为零）。，可以换 5 个小麦。（假定So, countries would spelizeheir production.So, both countries can gain from spelizing and trading.注意：此处的贸易利益是指的静态利益，是指贸易国在既定的要素供给下或在资源不变

13、的条件下所能获得的产出和福利的增长情况。包括两方面：1. 来自于专业化的利益，指各国通过参与国际分工，专门从事其效率相对最高的生产来获得额外的利益，提高的利用效率。2.来自于交换的利益。指通过贸易可买到本国不能生产或生产成本太高的产品，使消费的选择性增加，福利改善。四.的比较优势理论Trade Bases on Comparative Advantage: David Ricardo的比较优势理论解决了这个问题。他认为，如同一个人，一个国家通过在生产率方面具有最大比较优势的商品或服务的出口以及进口其比较优势较小的商品而从贸易中获利。下面分析比较优势如何产生的：Comparativeadvant

14、agecomesfromtherelativedifferenceoftechnology, and it is measured by relative productivity.产品的比较优势来自于生产技术的相对差别，可以用产品的相对劳动生产率来衡量。相对劳动生产率是不同产品的劳动生产率的比率。产品 A 的相对劳动生产率=产品 A 的人均产量其他产品的人均产量产品 A 的相对生产成本=产品 A 的成本其他产品的成本So,evenif onenation were themost productiveat producing everything and another were the l

15、east, they would both gain by tradingwith each other as long as theye comparative advantage.The law of comparative advantage: comparative advantage comes from the relative difference of productivities based on the relative difference of technologies. A nation should produce and export the commoditie

16、s of comparative advantage, and import the commodities of comparative disadvantage.比较优势理论：如果各国之间存在着劳动生产率的相对差别，就会出现生产成本的相对差别，从而使各国在不同的产品上具有比较优势。各国应该集中生产并出口其具有比较优势的产品，进口其具有比较劣势的产品。（原因和结论）。Table 1-3 Labor costhe U.S.In China1 wheat1 cloth2 hours1.5 hours4 hours1hour在封济中，价格是两种商品的比价。Table 1-4he U.S.InChi

17、naWith no trade Price of wheat Price of cloth0.5 布/1 麦2.0 麦/1 布1.5 布/1 麦0.67 麦/1 布贸易的结果，益。获得 1 个布的净收益，中国获得 1.33 的小麦的净收Both counties gain from trade and from spelization. (贸易的静态利益)。（please see the example, lawyer and secretaryextbook）.五. 机会成本不变条件下的贸易利益Ricardos Constant Opportunity CostsAnd The Produc

18、tion-sibilities Curve定义：机会成本是生产某种产品而必须放弃的能够生产除此以外最大可获收益的产品的代价。尽管机会成本不变是不现实的，从理论分析的逻辑来说，要求先分析机会成本不变条件下如何通过国际贸易获利；然后分析机会成本递增时如何从贸易中获利。Table 1-5Units of beef 100Units of wine 50U. S.France50150Figure 1.1U.S. PP curveFigure 1.2 France PP curve:beef452527.5wine751 个酒的机会成本是 2 个牛肉；法国是 1/3 个牛肉。由图可知，在生产可能性曲线

19、的斜率是 -2，法国是 1/3。由于机会成本不变，Now, we get a key word: Marginal rate of substitution in production (MRSp). 生产的边际替代率。在完全竞争下，交换的边际替代率（MRSt）等于生产的边际替代率(MRSp)。由于两国 MRSp 不同，存在价格差异，这就是贸易的基础。Figure 1.3U.S. GainsFigure 1.4 France Gains604040110结果，两国专业化生产，然后交换，其消费都超出封闭生产时的生产可能性曲线。dcIn, both countries gain from trad

20、e; because of spelization,their total output of beef and wine is highern before, and the extraoutput of production is shared by consumers in both countries.六.机会成本递增条件下的贸易利益Increasing Opportunity Costs AndThe Production-sibilities Curve机会成本递增的两个原因：不同的产品需要不同的要素密度；而且各种要素只能部分地互相替代。现在假定机会成本递增。We can see

21、it clearly. From N to M, the curve slope will and flatter.斜率的绝对值越来越小，价格曲线越来越平缓。e flatter开始时，酒的机会成本大，牛肉的机会成本小；随着生产点的移动，牛肉的机会成本越来越大，价格越来越高，而酒的机会成本却越来越小。在机会成本递增条件下，是什么费者的需求偏好。决定了酒和肉的价格比率？是消假定愿意消费酒和较少肉，选择 C 点。均衡的条件：生产可能性曲线、价格交换线和无差异曲线相切。因为无差异曲线的任何一点都是消费的边际替代率(MRSc)，所以，三条线相切，就是：MRSp = MRSc = MRSt .Figure

22、 1.5Increasing Opportunity CostsMbeef0wN假定消费者改变了偏好，愿意消费较多的肉和较少的酒，一条新的无差异曲线将在 D 点与 PP 曲线相切。与 C 点相比，消费了较多的肉和较少的酒。现在分析在机会成本递增条件下，和法国如何通过贸易获利。贸易之前，肉价低，酒价高。开展贸易之后，法国的情况则相反。出口肉，进口酒。为了多出口牛肉，必须多生产牛肉，生产从 C 点贸易开始以后，移到 A 点。出口 DC牛肉，进口 AD 酒。消费点在 C，高于贸易之前的无差异曲线。DTCwineFigure 1.6U.S. Gains from Trade: Increasing Opportunity CostsbeefADCCwineFigure 1.7France Gains from Trade: Increasing Opportunity CostsKJKH法国的情况刚好相反，同学自己分析。最后满足均衡