勞動生產(chǎn)率和比較優(yōu)勢：李嘉圖模型

1、YOU ARE WELCOME !.International Economics國際經(jīng)濟(jì)學(xué)主講：余道先ydxdhyhotmail.Chapter 3Labor Productivity and Comparative Advantage:The Ricardian Model勞動消費(fèi)率和比較優(yōu)勢：李嘉圖模型.PreviewIntroductionThe Concept of Comparative Advantage比較優(yōu)勢A One-Factor Economy單一要素經(jīng)濟(jì)Trade in a One-Factor World單一要素世界的貿(mào)易Comparative Advantage w

2、ith Many Goods多種產(chǎn)品的比較優(yōu)勢Adding Transport Costs and Nontraded Goods引入運(yùn)輸本錢和非貿(mào)易品Empirical Evidence on the Ricardian ModelSummary.Countries engage in international trade for two basic reasons:They are different from each other in terms of climate, land, capital, labor, and technology.They try to achieve

3、scale economies 規(guī)模經(jīng)濟(jì)in production.The Ricardian model is based on technological differences across countries.These technological differences are reflected in differences in the productivity of labor.Introduction.The Ricardian model uses the concepts of opportunity cost and comparative advantage.The

4、Concept of Comparative Advantage.For example，On Valentines Day the U.S. demand for roses is about 10 million roses.Growing roses in the U.S. in the winter is difficult.Heated greenhouses should be used.The costs for energy, capital, and labor are substantial.Resources for the production of roses cou

5、ld be used to produce other goods, say computers.The Concept of Comparative Advantage.Opportunity Cost時機(jī)本錢The opportunity cost of roses in terms of computers is the number of computers that could be produced with the same resources as a given number of roses.Comparative Advantage比較優(yōu)勢A country has a

6、comparative advantage in producing a goods if the opportunity cost of producing that goods in terms of other goods is lower in that country than it is in other countries. 假設(shè)一個國家在本國消費(fèi)某種產(chǎn)品的時機(jī)本錢用其他產(chǎn)品來衡量低于在其他國家消費(fèi)該種產(chǎn)品的時機(jī)本錢的話，那么這個國家在該種產(chǎn)品的消費(fèi)上具有比較優(yōu)勢。The Concept of Comparative Advantage.Suppose that in the U

7、.S. 10 million roses can be produced with the same resources as 100,000 computers.Suppose also that in South America 10 million roses can be produced with the same resources as 30,000 computers.This example assumes that South American workers are less productive than U.S. workers.The Concept of Comp

8、arative Advantage.If each country specializes in the production of the goods with lower opportunity costs, trade can be beneficial for both countries.Roses have lower opportunity costs in South America.Computers have lower opportunity costs in the U.S.The benefits from trade can be seen by consideri

9、ng the changes in production of roses and computers in both countries.The Concept of Comparative Advantage.Table 3-1: Hypothetical Changes in ProductionThe Concept of Comparative Advantage.The example in Table 3-1 illustrates the principle of comparative advantage: If each country exports the goods

10、in which it has comparative advantage (lower opportunity costs), then all countries can in principle gain from trade.假設(shè)每個國家都出口本國具有比較優(yōu)勢的商品低的時機(jī)本錢，那么每個國家都會從貿(mào)易中受害What determines comparative advantage? Answering this question would help us understand how country differences determine the pattern of trade

11、 (which goods a country exports).The Concept of Comparative Advantage.A One-Factor Economy 單一要素經(jīng)濟(jì)Assume that we are dealing with an economy (which we call Home). In this economy:Labor is the only factor of production.Only two goods (say wine and cheese) are produced.The supply of labor is fixed in e

12、ach country.The productivity of labor in each goods is fixed.Perfect competition prevails in all markets.The technology of Homes economy can be summarized by labor productivity in each industry, expressed in terms of unit labor requirements:The unit labor requirement is the number of hours of labor

13、required to produce one unit of output.Denote with aLW the unit labor requirement for wine (e.g. if aLW = 2, then one needs 2 hours of labor to produce one gallon of wine).Denote with aLC the unit labor requirement for cheese (e.g. if aLC = 1, then one needs 1 hour of labor to produce a pound of che

14、ese).A One-Factor Economy.The economys total resources are defined as L, the total labor supply. e.g. if L = 120, then this economy is endowed with 120 hours of labor or 120 workers.A One-Factor Economy.Production PossibilitiesThe production possibility frontier (PPF) 消費(fèi)能夠性邊境of an economy shows the

15、maximum amount of a goods (say wine) that can be produced for any given amount of another (say cheese), and vice versa. Or illustrates the different mixes of goods the economy can produce.The PPF of our economy is given by the following equation: aLCQC + aLWQW = L (3-1)From our previous example, we

16、get:QC + 2QW = 120A One-Factor Economy.L/aLWL/aLCFigure 2-1: Homes Production Possibility FrontierA One-Factor EconomyAbsolute value of slope equalsopportunity cost of cheese interms of wineFPHome wine production, QW, in gallonsHome cheese production, QC, in poundso.Relative Prices and SupplyThe par

17、ticular amounts of each goods produced are determined by prices.The relative price of goods X (cheese) in terms of goods Y (wine) is the amount of goods Y (wine) that can be exchanged for one unit of goods X (cheese).產(chǎn)品X對產(chǎn)品Y的相對價錢是用多少單位的Y能換回一單位的XA One-Factor Economy.Relative Prices and SupplyExamples

18、 of relative prices:If a price of a can of Coke is $0.5, then the relative price of Coke is the amount of $ that can be exchanged for one unit of Coke, which is 0.5.The relative price of a $ in terms of Coke is 2 cans of Coke per dollar.A One-Factor Economy.Denote with PC the dollar price of cheese

19、and with PW the dollar price of wine. Denote with wW the dollar wage in the wine industry and with wC the dollar wage in the cheese industry.There are no profits in our one-factor model,the hourly wage rate in the cheese sector will equal the value of what a worker can produce in an hour, PC/aLC.奶酪部

20、門的單位工資率等于一個工人在一個小時內(nèi)消費(fèi)的價值 The hourly wage rate in the wine sector will be PW/aLW.A One-Factor Economy.The above relations imply that if the relative price of cheese (PC / PW ) exceeds its opportunity cost (aLC / aLW), then the economy will specialize in the production of cheese.Or PC/aLCPW/aLW.In the

21、 absence of trade, both goods are produced, and therefore PC / PW = aLC /aLW. 在沒有國際貿(mào)易時，產(chǎn)品的相對價錢等于它們的相對單位產(chǎn)品勞動投入。A One-Factor Economy.Trade in a One-Factor WorldAssumptions of the model:There are two countries in the world (Home and Foreign).Each of the two countries produces two goods (say wine and ch

22、eese).Labor is the only factor of production.The supply of labor is fixed in each country.The productivity of labor in each goods is fixed.Labor is not mobile across the two countries.Perfect competition prevails in all markets.All variables with an asterisk refer to the Foreign country.Absolute Adv

23、antage絕對優(yōu)勢A country has an absolute advantage in a production of a goods if it has a lower unit labor requirement than the foreign country in this goods.Assume that aLC a*LC and aLW a*LWThis assumption implies that Home has an absolute advantage in the production of both goods. Another way to see th

24、is is to notice that Home is more productive in the production of both goods than Foreign.Even if Home has an absolute advantage in both goods, beneficial trade is possible.The pattern of trade will be determined by the concept of comparative advantage比較優(yōu)勢.Trade in a One-Factor World.Comparative Adv

25、antageAssume that aLC /aLW a*LC /a*LW(3-2)This assumption implies that the opportunity cost of cheese in terms of wine is lower in Home than it is in Foreign.In other words, in the absence of trade, the relative price of cheese at Home is lower than the relative price of cheese at Foreign.Home has a

26、 comparative advantage in cheese and will export it to Foreign in exchange for wine.Trade in a One-Factor World.F*P*L*/a*LWL*/a*LCForeign wine production, Q*W, in gallonsForeign cheese production, Q*C , in pounds+1Figure 3-2: Foreigns Production Possibility FrontierTrade in a One-Factor World.Determ

27、ining the Relative Price After TradeWhat determines the relative price (e.g., PC / PW) after trade? To answer this question we have to define the relative supply and relative demand for cheese in the world as a whole.把世界作為一個整體來確定奶酪的相對供應(yīng)和相對需求The relative supply of cheese equals the total quantity of

28、cheese supplied by both countries at each given relative price divided by the total quantity of wine supplied, (QC + Q*C )/(QW + Q*W).The relative demand of cheese in the world is a similar concept.Trade in a One-Factor World.2RDRD1QaLC/aLWa*LC/a*LWRSFigure 3-3: World Relative Supply and DemandTrade

29、 in a One-Factor WorldRelative priceof cheese, PC/PWRelative quantityof cheese, QC + Q*C QW + Q*WL/aLCL*/a*LW.Trade in a One-Factor WorldFirst,the RS curve shows that there is no supply of cheese if the world price drops below aLC/aLW. -Assume aLC/aLWa*LC/a*LW, Home will specialize in the production

30、 of cheese. -Home will specialize in the production of wine whenever PC/PWaLC/aLW , or PC/aLCPW/aLW. -Similarly,Foreign will specialize in wine production whenever PC/PWa*LC/a*LW, both Home and Foreign will specialize in cheese production. There will be no wine production, so that the relative suppl

31、y of cheese will become infinite.Fourth, At PC/PW=a*LC/a*LW, Foreign workers are indifferent between producing cheese and wine. We again have a flat section of the supply curve.Fifth, aLC/aLW PC/PW a*LC/a*LW, the relative supply of cheese is (L/aLC)/(L*/a*LW).The Gains from TradeIf countries special

32、ize according to their comparative advantage, they all gain from this specialization and trade.We will demonstrate these gains from trade in two ways.First, we can think of trade as a new way of producing goods and services (that is, a new technology).Trade in a One-Factor World.Another way to see t

33、he gains from trade is to consider how trade affects the consumption in each of the two countries.The consumption possibility frontier states the maximum amount of consumption of a goods a country can obtain for any given amount of the other commodity.In the absence of trade, the consumption possibi

34、lity curve is the same as the production possibility curve.Trade enlarges the consumption possibility for each of the two countries.Trade in a One-Factor World.Trade in a One-Factor WorldFigure 3-4: Trade Expands Consumption PossibilitiesTFPT *P *F *(a) Home(b) ForeignQuantityof wine, QWQuantityof c

35、heese, QCQuantityof wine, Q*WQuantityof cheese, Q*C.A Numerical ExampleWe must understand two crucial points: When two countries specialize in producing the goods in which they have a comparative advantage, both countries gain from trade. Comparative advantage must not be confused with absolute adva

36、ntage; it is comparative, not absolute, advantage that determines who will and should produce a good. .A Numerical ExampleaLC /aLW = 1/2 a*LC /a*LW = 2Unit labor requirements for domestic and foreign countriesCheeseWineDomesticaLC = 1 hour/kgaLW = 2 hours/LForeigna*LC = 6 hours/kga*LC = 3 hours/L.A

37、Numerical ExampleThe domestic country is more efficient in both industries, but it has a comparative advantage only in cheese production.The foreign country is less efficient in both industries, but it has a comparative advantage in wine production.A Numerical ExampleWith trade, the equilibrium rela

38、tive price of cheese must be between aLC /aLW = 1/2 and a*LC /a*LW = 2Suppose that PC /PW = 1 in equilibrium.In words, one kg of cheese trades for one liter of wine.A Numerical ExampleIf the domestic country does not trade, it can use one hour of labor to produce 1/aLW = 1/2 liter of wine.If the dom

39、estic country does trade, it can use one hour of labor to produce 1/aLC = 1 kg of cheese, sell this amount to the foreign country at current prices to obtain 1 liter of wine.If the foreign country does not trade, it can use one hour of labor to produce 1/a*LC = 1/6 kg of cheese.If the foreign countr

40、y does trade, it can use one hour of labor to produce 1/a*LW = 1/3 liter of wine, sell this amount to the domestic country at current prices to obtain 1/3 kg of cheese.Relative Wages相對工資The relative wage of a countrys workers is the amount they are paid per hour, compared with the amount workers in

41、another country are paid per hour.This wage rate lies between the ratios of the two countries productivities in the two industries.相對工資率位于兩國的兩個工業(yè)部門的相對勞動消費(fèi)率之間.Relative WagesSuppose that PC = $12/kg and PW = $12/LSince domestic workers specialize in cheese production after trade, their hourly wages wi

42、ll be(1/aLC)PC = (1/1)$12 = $12Since foreign workers specialize in wine production after trade, their hourly wages will be (1/a*LW)PW = (1/3)$12 = $4 The relative wage of domestic workers is therefore$12/$4 = 3.Relative WagesSo the relative wage lies between the ratio of the productivities in each i

43、ndustry.The domestic country is 6/1 = 6 times as productive in cheese production, but only 3/2 = 1.5 times as productive in wine production.The domestic country has a wage rate 3 times as high as that in the foreign country.These relationships imply that both countries have a cost advantage in produ

44、ction.The cost of high wages can be offset by high productivity.The cost of low productivity can be offset by low wages.Relative WagesBecause foreign workers have a wage that is only 1/3 the wage of domestic workers, they are able to attain a cost advantage (in wine production), despite low producti

45、vity.Because domestic workers have a productivity that is 6 times that of foreign workers (in cheese production), they are able to attain a cost advantage, despite high wages.Relative WagesIn the Ricardian model, relative wages reflect relative productivities of the two countries.Is this an accurate

46、 assumption? Some argue that low wage countries pay low wages despite growing productivity, putting high wage countries at a cost disadvantage.But evidence shows that low wages are associated with low productivity.Productivity and WagesSource: International Labor Organization, World Bank, Bureau of

47、Labor Statistics, and Orley Ashenfelter and Stepan Jurajda, “Cross-country Comparisons of Wage Rates, working paper, Princeton University.Relative WagesOther evidence shows that wages rise as productivity rises.In 2000, South Koreas labor productivity was 35% of the U.S. level and its average wages

48、were about 38% of U.S. average wages.After the Korean War, South Korea was one of the poorest countries in the world, and its labor productivity was very low. Even by 1975, average wages in South Korea were still only 5% of U.S. average wages.Disconceptions About Comparative AdvantageProductivity an

49、d CompetitivenessThe Pauper Labor Argument貧民勞動爭論Exploitation剝削.Comparative Advantage with Many Goods多種產(chǎn)品Setting Up the ModelBoth countries consume and are able to produce a large number, N, of different goods.The technology of each country can be described by its unit labor requirement for each good

50、. .Comparative Advantage with Many GoodsRelative Wages and SpecializationThe pattern of trade will depend on the ratio of Home to Foreign wages.Goods will always be produced where it is cheapest to make them.For example, it will be cheaper to produce goods i in Home if waLi w/w*.Comparative Advantag

51、e with Many GoodsTable 3-3: Home and Foreign Unit Labor Requirements.Which country produces which goods?A country has a cost advantage in any good for which its relative productivity is higher than its relative wage.對于一個國家來說，相對消費(fèi)率高于相對工資率的產(chǎn)品具有本錢優(yōu)勢If, for example, w/w* = 3, Home will produce apples, b

52、ananas, and caviar, while Foreign will produce only dates and enchiladas.Both countries will gain from this specialization.Comparative Advantage with Many Goods.Determining the Relative Wage in the Multigood Model相對工資確實定To determine relative wages in a multigood economy we must look behind the relat

53、ive demand for goods (i.e., the relative derived demand).要確定在多種產(chǎn)品經(jīng)濟(jì)中的相對工資，我們必需根據(jù)產(chǎn)品的相對需求來推知隱含的對勞動的相對需求 The relative demand for Home labor depends negatively on the ratio of Home to Foreign wages.Comparative Advantage with Many Goods.310Apples8Bananas4Caviar2Dates0.75EnchiladasRDComparative Advantage

54、with Many GoodsFigure 3-5: Determination of Relative WagesRSRelative wageRate, w/w*Relative quantityof labor, L/L*.Transportation Costs and Non-traded GoodsThe Ricardian model predicts that countries should completely specialize in production.But this rarely happens for primarily three reasons:1. Mo

55、re than one factor of production reduces the tendency of specialization.2. Protectionism.3. Transportation costs reduce or prevent trade, which may cause each country to produce the same good or service.Transportation Costs and Non-traded Goods Non-traded goods and services (ex., haircuts and auto repairs) exist due to high transportation costs.Countries tend to spend a large fraction of national income on non-traded goods and servi