教学课件：《国际贸易理论与政策》1.ppt

1、International Trade:Theory and Policy analysis Part I General Framework and Basic Instruments for Trade Analysis New perspective and models in trade analysis Lecture 1.Newly developed points of view on International Trade1.1 International trade:recent trend Two key words:globalization+Post-financial

2、 crisis Globalization:what is,why,how?Globalization is the process of international integration arising from the interchange of world views,products,ideas,and other aspects of culture.(wiki.)Post-crisis=post-financial crisis:both a period comes after a financial tsunami and a situation of the world

3、economy during the 5-10 years following the financial crises.(赵伟，2012，新华文摘2012（7）Trade implication of globalization Two main view on globalization Thomas Friedman the world is flat-A Brief History of the Twenty-First Century.2005,2007 3 versions of globalization:V.1:power of nation+imperialist attit

4、udes;V.2:power of MNCs;V.3:flat world keywords:web+upload+outsourcing+offs horing supply-chain+e-comerce.Richard Boldwin(2011):two waves:1820-1914;1960-present New stage unbundling:goods flow with ideasAttachment:Ten flatteners:#1:Collapse of the Berlin Wall 11/9/89:#2:Netscape 8/9/95($28)/=digitiza

5、tion.#3:Workflow software:the standards and technologies that allowed work to flow.#4:Uploading:Communities uploading and collaborating on online projects.#5:Outsourcing:#6:Offshoring:#7:Supply-chaining:(Wal-Mart as the best example)#8:Insourcing:in which the companys employees perform services beyo

6、nd shipping for another company.#9:Informing:Google and other search engines are the prime example.#10:The Steroids=(类固醇类固醇=数字化数字化+移动移动+个人的个人的+虚拟的虚拟的):source:wikepedia:http:/en.wikipedia.org/wiki/The_World_Is_Flat Attachment:Boldwin(1)Attachment:Boldwin(2)Globalizations first unbundlingAttachment:Bo

7、ldwin(3)Globlizations second unbundling 1.2.New view:introducing borders and distance McCallum(John,1995):borders matters:He made the 1st crude estimation on border effects over Canada-US trade.finding that trade between Ca provinces is 22 times higher than trade between Ca provinces and US states d

8、espite the two countries very integrated US-Cad border effect:gravity type regression:(1.1)where DUMMYij is a dummy=1 if both i&j are Ca provinces,and 0 otherwise.Note:it does not have data on trade among US states;The coefficient of interest is,which measures the importance of the US-Ca border for

9、trade.It finds that ,meaning that,controlling for size and distance,trade between 2 Ca provinces is 22 times larger than trade between a Ca province and a US state.Gravity Equations in trade nA simplest form:Usually gives,1;is scaling constant:1km=$1.The model was first used by Tinbergen(1962).Trade

10、 flow btwGravity equation/models=a model being used to predict bilateral trade flows based on the economic sizes of(GDP)and distance between two spatial units.The coefficients are surprisingly stable over time and space.1.3 Theoretical gravity equation model:Being developed by Anderson and Van Winco

11、op(2003)and shows that a combination of omitted variable bias,and the small size of the Canadian economy relative to the US leads to such large estimates of the border effect.based on some important assumptions:goods are differentiated by country of origin,each country specialized in a single good,a

12、nd the supply of each good is fixed.Identical homothetic preferences(位似偏好）,approximated by CES.Multiplicative transportation costs.Each country j chooses amount to import from each country i(qij)by maximizing utility subject to a budget constraint,=elasticity of substitution btw goods from any twoco

13、untries PropositionProposition 1:If assume symmetric transport costs,so that then the prices pis that are solution to Eq.4-6 are such that,Proof.nprice indices Pi,Pj are measures of bilateral trade resistance.n If a country is isolated from the rest of the world,prices/domestic price index will be h

14、igh.It imports little from rest world.nIf prices are high in a country,it is relatively easy to capture a large market share in this country for foreign exporters.1.4 Gravity model:from complication to simplification With this simplification,then can we get a very simple equation with which to predi

15、ct bilateral trade flows:with the price indices solution to,1.5 Main predictions of the theoretical model:Size matters:larger(richer)countries import more,and they export more.Trade barriers matter:the larger bilateral trade barriers between any two countries i and j(ij large),the less they trade wi

16、th one another.for given bilateral trade barriers,more remote countries import(and export)less.In other words,the more isolated a country is from the rest of the world,which will be captured by a larger price index,the less this country imports.Alternatively,a country which charges high prices will

17、export relatively little.(more interesting prediction)price indices depend on relative size and relative trade barriers.Next are some interesting implications derived from the determination of price indices(multilateral trade resistance indices).(Even more interesting prediction)more implication:If

18、suppose within country trade is frictionless ,then the model predicts,Trade barriers reduce(size adjusted)trade between large countries more than between small countries.Trade barriers raise(size-adjusted)trade within small countries more than within large countries.Trade barriers raise the ratio of

19、(size-adjusted)trade within country 1 relative to(size-adjusted)trade between country 1 and country 2 more the smaller is country 1 and the larger is country 2.Reason:demand side:very large country,most of what is consumed is produced domestically.a change in trade barriers will only affect the good

20、s that are imported,which represent only a small fraction of all the goods consumed in this country.Hence,changes in trade barriers have little effects on its domestic prices,and on the trade resistance of that country.On the supply side:the larger the country,the larger the supply of this good in t

21、he world,and the smaller the price of that good(relative to the price of a good produced by a smaller country).Hence,larger countries tend to charge lower prices.Demand/supply effectsTopics for rethinking and Recommended readings全球化与后危机：对于国际贸易的意义：参考文献：赵伟，2012，新华文摘2012（7）弗里德曼(2005)：世界是平的Boldwin(2011)

22、:new stage unbundling worldGravity model:文献综述参考文献 Anderson,J.,van Wincoop,E.Gravity with Gravitas:A Solution to the Border Puzzle.American Economic Review(2003).贸易引力模型：来自中国的实证与启示 4页 从贸易引力模型看中国双边贸易安排 14页 双边国际贸易引力模型中地区生产率的经验研究 10页 双边国际贸易引力模型中地区生产率的经验研究 10页 基于贸易引力模型的上海合作组织成员国贸易流量影响因素比较研究 4页 哈萨克斯坦对外贸易基于

23、贸易引力模型的实证研究 4页 贸易引力模型对中国双边贸易的实证检验及贸易潜力分析 2页 International Trade:Theory and Policy analysis Part I General Framework and Basic models for Trade Analysis New view and models in trade analysis Lecture 2.Krugman Model on International Trade2.1.introduction:Starting from old modelsOld models:a summing up

24、:Ricardian model of trade(1817)Countries differ in their technology.Motive for trade:comparative advantages.Key assumption:moving goods is easier than moving technology Heckscher-Ohlin model of trade(1933)Countries differ in their factor endowments.Motive for trade:endogenous differences in technolo

25、gy.Key assumption:it is easier to trade goods than factors.Key finding:trade alone may equalize factor prices.Empirical challenges Old models of trade seem contradicted with the empirical evidences on trade increasingly:Countries with seemingly similar technologies trade.Countries with seemingly sim

26、ilar factor endowments trade.A large fraction of trade is two-way trade within industry(intra-industry trade).Size and distance seem to matter much more than any difference in technology and factor endowment.Krugmans breakthrough Krugam(1980)offers an entirely new approach to international trade,and

27、 to the motives for international trade.He develops(making use of two models:a.Dornbusch,Fischer and Samuelson,1977;b.Dixit and Stiglitz,1977)a very simple(simplistic)model of trade in differentiated good with increasing returns to scale.unlike Ricardian model,or H-O model,he explains,with this mode

28、l,that even exactly identical countries would trade with one another,and would gain from trade.2.2 Krugman model:changing assumptionsBasic assumptions:Countries have identical technologies,factor endowments,preferences.Differentiated goods(love for variety)consumers want to consume all possible good

29、s.Increasing returns to scale countries specialize in producing a subset of goods.Key assumption:Consumers preferences=love for variety.Producers:benefit from increasing returns to scale.Institution:imperfect competition.Key simplifying assumptions Iso-elastic preferences.Fixed cost+constant margina

30、l cost technology.Monopolistic competition with many firms.Multiplicative trade costs.2.2 Krugman model:AutarkyConsider an economy in autarky.-being populated by a mass L of identical agents,who work,consume,and own domestic firms.-It is isomorphic(同构）同构）to an economy with a single representative co

31、nsumer,who supplies L units of labor on a competitive labor market on one hand,and pursues profit maximizing as an independent producer on another hand.-The representative consumer derives utility from consuming a continuum of differentiated goods,which are paid for using his labor income.If a consu

32、mer has access to all varietiesin the set (to be determined endogenously in equilibrium,he maximizes his utility with equation,=elasticity of substitution btw any 2 varieties(parameter)(2.1)Situation in Demand side The isoelastic preferences give the simple isoelastic demand structure for each commo

33、dity,(2.2)(2.3)Technology and pricing=supply condition Increasing returns to scale technology:Each firm sells a single variety.It is a monopolist for that variety.Production takes place under increasing returns to scale.which is modelled as a fixed cost of starting production,f units of labor,and a

34、variable cost,1/units of labor per unit producedIso-elastic demand constant markup(加成）over marginal cost:Given technology the firm faces,and given isoelastic demand for each variety,the optimal pricing strategy for each firm is to charge a constant price over marginal cost,(2.4)(2.5)=1/(1-)Profits m

35、aximization No matter how much competition firms are facing,i.e.no matter how many varieties are available,the elasticity of substitution between any two varieties is constant,so that firm always charge the same price（a properties of Dixit-Stiglitz model）.Given this pricing strategy,the firm selling

36、 q()units of good,earns net profits (),(2.6)How the number of firms is determined with free entry？assume free entry.As long as profits are positive,new firms will enter.With more firms enter,consumers substitute increasing part of their spending from existing suppliers towards new suppliers,which de

37、presses the profits of existing firms.This goes on until profits are driven to zero.With symmetric,then each firm charges the same price,sells the same quantity,and earns the same profits.the total number of firms in the economy is determined simply through labor market clearing,(FE)(LMC)Welfare inc

38、reases with size,Among other things,it seems that the ideal price index,which is an inverse measure of welfare,is increasing with the size of a country.Larger countries produce more varieties,their consumers are better off since they have a preference for variety,then,(2.7)2.3 Trade equilibrium Assu

39、mption:2 countries,only differ in size(L,L).Iceberg transportation costs 1.Segmented markets:Domestic firms charge a price p for their own market,and a price p if they sell abroad.The price set by foreign firms is similarly.=both trade barriers and relative abundance of varieties affect trade,If one

40、 unit of good is shippedabroad,only a fraction 1/=(1)arrives.Production and profitsGiven the prices,firms produce qD(p)units for their domestic market,and export qX(p)units abroad.The total production of each firm is q=qD+qX,and the total net profits they earn is,after rearranging,is .Exactly as in

41、autarky,free entry drives down profits to zero,so that,Firms produce both for domestic and foreign consumers,Profits derived from global sales,Free entry drives down global profits to zero,Number of firms Number of firms pinned down by aggregate resource constraint(labor market clearing),(LMC)Note:n

42、umber of firms same as in autarky(due to constant mark-ups).Corollary:number of products unaffected by changes in trade barriers.(the scale of production is unaffected by the opening to trade.)Aggregate trade Define the relative wage,=w/w,and let w=1.nAggregate trade flows,(2.8)with a scaling consta

43、nt.it can be solved for theprice index(=as a function of relative wages),Foreign price index,Two margins of trade expansion:Intensive versus extensive margin:an important prediction of the model is,when a country goes from autarky to some costly trade(goes from+1 to some number above 1),all the new

44、trade comes on the extensive margin.Consumers do not consume more of the goods they used to in autarky,n remains unchanged.They actually consume less of each(but the same number of those domestically produced goods),and they just start consuming new goods imported from abroad(all of the n foreign va

45、rieties).However,when a country further liberalizes trade(goes down),the set of imported goods remains exactly unchanged.n is constant.Consumers only consume more of each imported variety.this prediction is strongly violated with data on the real world,and attracted much empirical attention.Predicti

46、on:Wages and market size(Economic Geography)relative wage will be pinned down by the equilibrium in the goods market.specifying goods market clearing condition:market clearing for home goods,or for foreign goods,or trade balance.(informative way),e.g.,Xfob=X f o.b,which givesIn a large market:More c

47、heap(domestic)varieties lower price index.consumers are less willing to import(expensive)foreign varieties.to restore trade balance,currency appreciates.relative wage increases.Note:a larger market has higher nominal wages and a lower priceindex,so higher real wages.Prediction:Gains from trade do no

48、t come from increased variety Welfare depends on number of goods and prices,nNumber of varieties and local prices are constant,nGain from trade only comes from cheaper foreign goods,rather than from more foreign goods.nNot:only true on average,because relative wages adjust.Prediction 4:HM effect Hom

49、e market effect:increasing returns to scale industries will tend to locate in the countries with the largest market,and export their goods to other countries.See krugman(1980).Recommended readingsand homework:Readings:Dornbusch,Fischer and Samuelson,1977;Dixit and Stiglitz,1977;Krugman,1980 Krugman

50、and helpman,1985 Homework Tracing the latest development in this field Home-market effect empirics related to China Making yourself familiar with other four approaches of modeling monopolistic competition Suggestion for improving the textbook.International Trade:Theory and Policy analysis Part I Gen