1. Copyright © 2003 Pearson Education, Inc.Slide 6-1  模型目的。  內生變數：決定模型兩軸。 返回 返回  行為法則：畫出模型曲線。  均衡：決定均衡之內生變數。  外生衝擊 判斷是否為外生變數改變？ 判斷此外生變數之改變將影響哪些行為法則？ 判斷此外生變數之改變造成行為法則何種影響？ 學習經濟模型五步驟 內內生變數

2. Copyright © 2003 Pearson Education, Inc.Slide 6-2 內生變數 Price, cost (per watch) Quantity of watches produced and demanded

3. Copyright © 2003 Pearson Education, Inc.Slide 6-3  模型目的。  內生變數：決定模型兩軸。  行為法則：畫出模型曲線。 返回 返回  均衡：決定均衡之內生變數。  外生衝擊 判斷是否為外生變數改變？ 判斷此外生變數之改變將影響哪些行為法則？ 判斷此外生變數之改變造成行為法則何種影響？ 學習經濟模型五步驟 行行為法則

4. Copyright © 2003 Pearson Education, Inc.Slide 6-4  External Economies and Increasing Returns External economies can give rise to increasing returns to scale at the level of the national industry. Forward-falling supply curve –The larger the industry’s output, the lower the price at which firms are willing to sell their output. The Theory of External Economies

5. Copyright © 2003 Pearson Education, Inc.Slide 6-5  External Economies and the Patter of Trade A country that has large production in some industry will tend to have low costs of producing that good. 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. –Figure 6-9 illustrates a case where a pattern of specialization established by historical accident is persistent. External Economies and International Trade

6. Copyright © 2003 Pearson Education, Inc.Slide 6-6 Figure 6-9: External Economies and Specialization External Economies and International Trade AC SWISS Q1Q1 P1P1 Price, cost (per watch) Quantity of watches produced and demanded AC THAI 2 1 C0C0 D 說明

7. Copyright © 2003 Pearson Education, Inc.Slide 6-7  模型目的。  內生變數：決定模型兩軸。  行為法則：畫出模型曲線。  均衡：決定均衡之內生變數。 返回 返回  外生衝擊 判斷是否為外生變數改變？ 判斷此外生變數之改變將影響哪些行為法則？ 判斷此外生變數之改變造成行為法則何種影響？ 學習經濟模型五步驟 均均衡

8. Copyright © 2003 Pearson Education, Inc.Slide 6-8  Trade and Welfare with External Economies Trade based on external economies has more ambiguous effects on national welfare than either trade based on comparative advantage or trade based on economies of scale at the level of the firm. –An example of how a country can actually be worse off with trade than without is shown in Figure 6-10. External Economies and International Trade

9. Copyright © 2003 Pearson Education, Inc.Slide 6-9 D THAI Figure 6-10: External Economies and Losses from Trade External Economies and International Trade AC SWISS Price, cost (per watch) Quantity of watches produced and demanded AC THAI C0C0 2 P2P2 P1P1 1 D WORLD

10. Copyright © 2003 Pearson Education, Inc.Slide 6-10  Dynamic Increasing Returns 步驟 步驟 Learning curve 步驟 步驟 –It relates unit cost to cumulative output. ( 圖例 ）（ 步驟 ） 圖例 步驟 –It is downward sloping because of the effect of the experience gained though production on costs. （圖例）圖例 Dynamic increasing returns –A case when costs fall with cumulative production over time, rather than with the current rate of production. Dynamic scale economies justify protectionism. –Temporary protection of industries enables them to gain experience (infant industry argument). External Economies and International Trade

11. Copyright © 2003 Pearson Education, Inc.Slide 6-11 Unit cost Cumulative Output 返回 返回 External Economies and International Trade

12. Copyright © 2003 Pearson Education, Inc.Slide 6-12 Figure 6-11: The Learning Curve 返回 返回 External Economies and International Trade L Unit cost Cumulative output L*L* C*0C*0 C1C1 QLQL 步驟

13. Copyright © 2003 Pearson Education, Inc.Slide 6-13  模型目的。  內生變數：決定模型兩軸。  行為法則：畫出模型曲線。  均衡：決定均衡之內生變數。 返回 返回  外生衝擊 判斷是否為外生變數改變？ 判斷此外生變數之改變將影響哪些行為法則？ 判斷此外生變數之改變造成行為法則何種影響？ 學習經濟模型五步驟 均均衡

14. Copyright © 2003 Pearson Education, Inc.Slide 6-14 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.  Economies of scale can be internal or external.  The presence of scale economies leads to a breakdown of perfect competition.  Trade in the presence of economies of scale must be analyzed using models of imperfect competition.

15. Copyright © 2003 Pearson Education, Inc.Slide 6-15 Summary  In monopolistic competition, an industry contains a number of firms producing differentiated products.  Intraindustry trade benefits consumers through greater product variety and lower prices.  In general, trade may be divided into two kinds: Two-way trade in differentiated products within an industry (intraindustry trade). Trade in which the products of one industry are exchanged for products of another (interindustry trade).

16. Copyright © 2003 Pearson Education, Inc.Slide 6-16 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 competitive. Markets must be geographically segmented.  External economies give an important role to history and accident in determining the pattern of international trade.  When external economies are important, countries can conceivably lose from trade.