【正文】 e production in some industry will tend to have low costs of producing that good（大規(guī)模從事某一行業(yè)產(chǎn)品生產(chǎn)的國家往往具有較低的生產(chǎn)成本） . External Economies and International Trade 69 ? Countries that start out as large producers in certain industries tend to remain large producers even if some other country could potentially produce the goods more cheaply（如果一國在某些行業(yè)是主要的生產(chǎn)者，那么即使其他國家能夠以更低的價格生產(chǎn)該種產(chǎn)品，該國也會傾向于保持其主要生產(chǎn)者的地位） . External Economies and International Trade 70 ? Countries If external economies exist, the pattern of trade may be due to historical accidents: countries that start as large producers in certain industries tend to remain large producers even if another country could potentially produce more cheaply. ? Figure 69 illustrates a case where a pattern of specialization established by historical accident is persistent. External Economies and International Trade 71 Figure 69: External Economies and Specialization External Economies and International Trade ACSWISS Q1 P1 Price, cost (per watch) Quantity of watches produced and demanded ACTHAI 2 1 C0 D 72 ? Trade and Welfare with External Economies ? Trade based on external economies has more ambiguous effects on national welfare than either trade based on parative advantage or trade based on economies of scale at the level of the firm（基于外部經(jīng)濟的貿(mào)易比基于比較優(yōu)勢或內(nèi)部規(guī)模經(jīng)濟的貿(mào)易對福利的影響要模糊得多） . ? An example of how a country can actually be worse off with trade than without is shown in Figure 610. External Economies and International Trade 73 External Economies and International Trade Trade and Welfare with External Economies ? Trade based on external economies has an ambiguous effect on national welfare. ? There may be gains to the world economy by concentrating production of industries with external economies. ? But there is no guarantee that the right country will produce a good subject to external economies. ? It is even possible that a country is worse off with trade than it would have been without trade: a country may be better off if it produces everything for its domestic market rather than pay for imports. 74 Figure 610: External Economies and Losses from Trade External Economies and International Trade ACSWISS P1 Price, cost (per watch) Quantity of watches produced and demanded ACTHAI 2 1 C0 DTHAI DWORLD P2 75 ? Dynamic Increasing Returns（動態(tài)收益遞增） ? We have considered cases where external economies depend on the amount of current output at a point in time. ? But external economies may also depend on the amount of cumulative output over time. ? Dynamic increasing returns to scale exist if average costs fall as cumulative output over time rises. External Economies and International Trade 76 ? Dynamic Increasing Returns（動態(tài)收益遞增） ? Learning curve（學習曲線） ? It relates unit cost to cumulative output（把單位成本和累積提高的產(chǎn)量聯(lián)系在一起） . ? It is downward sloping because of the effect of the experience gained though production on costs（向下傾斜是因為通過生產(chǎn)逐漸積累的經(jīng)驗使成本降低） . External Economies and International Trade 77 ? Dynamic increasing returns（動態(tài)收益遞增） ? A case when costs fall with cumulative production over time, rather than with the current rate of production（是指這樣一種情況，即成本隨著積累產(chǎn)量而非當前勞動生產(chǎn)率的提高而下降） . External Economies and International Trade 78 ? Dynamic scale economies justify protectionism（動態(tài)規(guī)模經(jīng)濟效應為保護主義提供了依據(jù)） . ? Temporary protection of industries enables them to gain experience（對產(chǎn)業(yè)的暫時保護可以使這些行業(yè)獲得經(jīng)驗） (infant industry argument). External Economies and International Trade 79 Figure 611: The Learning Curve External Economies and International Trade L Unit cost Cumulative output L* C*0 C1 QL 80 External Economies and International Trade ? Like external economies of scale at a point in time, dynamic increasing returns to scale can lock in an initial advantage or a head start in an industry. ? Like external economies of scale at a point in time, dynamic increasing returns to scale can be used to justify protectionism. ? Temporary protection of industries enables them to gain experience: infant industry argument. ? But temporary is often for a long time, and it is hard to identify when external economies of scale really exist. 81 Summary ? Trade can result from increasing returns or economies of scale, that is, from a tendency of unit costs to be lower at larger levels of output（貿(mào)易是由規(guī)模報酬遞增或規(guī)模效應增強引起的，就是說是由隨著產(chǎn)出水平的提高，單位成本降低引起的） . ? Economies of scale can be internal or external. 82 ? The presence of scale economies leads to a breakdown of perfect petition（規(guī)模經(jīng)濟的存在破壞了完全競爭） . ? Trade in the presence of economies of scale must be analyzed using models of imperfect petition（在分析規(guī)模經(jīng)濟條件下的貿(mào)易時必須用不完全競爭模型） . Summary 83 Summary ? In monopolistic petition, an industry contains a number of firms producing differentiated products（在壟斷競爭中，一個行業(yè)包含多個生產(chǎn)不同產(chǎn)品的廠商） . ? Intraindustry trade benefits consumers through greater product variety and lower prices（產(chǎn)業(yè)內(nèi)貿(mào)易通過產(chǎn)品多樣性和更低的價格來使消費者獲益） . 84 ? In general, trade may be divided into two kinds: ? Twoway trade in differentiated products within an industry （產(chǎn)業(yè)內(nèi)部不同產(chǎn)品的雙向貿(mào)易）(intraindustry trade). ? Trade in which the products of one industry are exchanged for products of another（用一產(chǎn)業(yè)的產(chǎn)品去交換另一產(chǎn)業(yè)的產(chǎn)品的貿(mào)易） (interindustry trade). Summary 85 Summary ? Dumping occurs when a firm charges a lower price abroad than it charges domestically. ? Dumping can occur only if two conditions are met: ? The industry must be imperfectly petitive. ? Markets must be geographically segmented. 86 ? External economies give an important role to history and accident in determining the pattern of international trade（外部經(jīng)濟使歷史和偶然因素在決定國際貿(mào)易模式時發(fā)揮重要