《国际经济学》教师手册及课后习题答案（克鲁格曼，第六版）imch

HAPTER 6

ECONOMIES OF SCALE, IMPERFECT COMPETITION, AND INTERNATIONAL TRADE

Chapter Organization

Economies of Scale and International Trade: An Overview Economies of Scale and Market Structure The Theory of Imperfect Competition

Monopoly: A Brief Review

Monopolistic Competition

Limitations of the Monopolistic Competition Model Monopolistic Competition and Trade

The Effects of Increased Market Size

Gains from an Integrated Market: A Numerical Example Economies of Scale and Comparative Advantage The Significance of Intraindustry Trade

Why Intraindustry Trade Matters Case Study: Intraindustry Trade in Action: The North American Auto Pact Dumping

The Economics of Dumping Case Study: AntiDumping as Protection

Reciprocal Dumping

The Theory of External Economies

Specialized Suppliers Labor Market Pooling Knowledge Spillovers External Economies and Increasing Returns External Economies and International Trade

External Economies and the Pattern of Trade Trade and Welfare with External Economies Box: Tinseltown Economics Dynamic Increasing Returns Summary

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Appendix: Determining Marginal Revenue

CHAPTER OVERVIEW

In previous chapters, trade between nations was motivated by their differences in factor productivity or relative factor endowments. The type of trade which occurred, for example of food for manufactures, is based on comparative advantage and is called interindustry trade. This chapter introduces trade based on economies of scale in production. Such trade in similar productions is called intraindustry trade, and describes, for example, the trading of one type of manufactured good for another type of manufactured good. It is shown that trade can occur when there are no technological or endowment differences, but when there are economies of scale or increasing returns in production.

Economies of scale can either take the form of 1) external economies whereby the cost per unit depends on the size of the industry but not necessarily on the size of the firm; or as 2) internal economies, whereby the production cost per unit of output depends on the size of the individual firm but not necessarily on the size of the industry. Internal economies of scale give rise to imperfectly competitive markets, unlike the perfectly competitive market structures that were assumed to exist in earlier chapters. This motivates the review of models of imperfect competition, including monopoly and monopolistic competition. The instructor should spend some time making certain that students understand the equilibrium concepts of these models since they are important for the justification of intraindustry trade.

In markets described by monopolistic competition, there are a number of firms in an industry, each of which produces a differentiated product. Demand for its good depends on the number of other similar products available and their prices. This type of model is useful for illustrating that trade improves the trade-off between scale and variety available to a country. In an industry described by monopolistic competition, a larger market -- such as that which arises through international trade -- lowers average price (by increasing production and lowering average costs) and makes available for consumption a greater range of goods. While an integrated markets also supports the existence of a larger number of firms in an industry, the model presented in the text does not make predictions about where these industries will be located.

It is also interesting to compare the distributional effects of trade when motivated by comparative advantage with those when trade is motivated by increasing returns to scale in

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production. When countries are similar in their factor endowments, and when scale economies and product differentiation are important, the income distributional effects of trade will be small. You should make clear to the students the sharp contrast between the predictions of the models of monopolistic competition and the specific factors and Heckscher-Ohlin theories of international trade. Without clarification, some students may find the contrasting predictions of these models confusing.

Another important issue related to imperfectly competitive markets is the practice of price discrimination, namely charging different customers different prices. One particularly controversial form of price discrimination is dumping, whereby a firm charges lower prices for exported goods than for goods sold domestically. This can occur only when domestic and foreign markets are segmented. While there is no good economic justification for the view that dumping is harmful, it is often viewed as an unfair trade practice.

The other type of economies of scale, external economies, has very different economic implications than internal economies. Since external economies of scale occur at the industry level rather than the firm level, it is possible for there to be many small competitors in an industry, in contrast to the structure which develops under internal economies of scale. Under external economies, trade may not be beneficial to all countries and there may be some justification for protectionism. Dynamic scale economies, which arise when unit production costs fall with cumulative production over time, rather than with current levels of production, also provide a potential justification for protectionism.

ANSWERS TO TEXTBOOK PROBLEMS

1. Cases a and d reflect external economies of scale since concentration of the production

of an industry in a few locations reduces the industry's costs even when the scale of operation of individual firms remains small. External economies need not lead to

imperfect competition. The benefits of geographical concentration may include a greater variety of specialized services to support industry operations and larger labor markets or thicker input markets. Cases b and c reflect internal economies of scale and occur at the level of the individual firm. The larger the output of a product by a particular firm, the lower its average costs. This leads to imperfect competition as in petrochemicals, aircraft, and autos.

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2.

The profit maximizing output level of a monopolist occurs where marginal revenue equals marginal cost. Unlike the case of perfectly competitive markets, under monopoly marginal revenue is not equal to price. Marginal revenue is always less than price under imperfectly competitive markets because to sell an extra unit of output the firm must lower the price of all units, not just the marginal one.

3.

By concentrating the production of each good with economies of scale in one country rather than spreading the production over several countries, the world economy will use the same amount of labor to produce more output. In the monopolistic competition model, such a concentration of labor benefits the host country, which can also capture some monopoly rents, while it may hurt the rest of the world which could then face higher prices on its consumption goods. In the external economies case, such monopolistic pricing behavior is less likely since imperfectly competitive markets are less likely.

4.

Although this problem is a bit tricky and the numbers don't work out nicely, a solution does exist. The first step in finding the solution is to determine the equilibrium number of firms in the industry. The equilibrium number of firms is that number, n, at which price equals average cost. We know that AC=F/X + c , where F represents fixed costs of production, X represents the level of sales by each firm, and c represents marginal costs. We also know that P=c+ (1/bn), where P and b represent price and the demand parameter. Also, if all firms follow the same pricing rule, then X=S/n where S equals total industry sales. So, set price equal to average cost, cancel out the c's and replace X by S/n. Rearranging what is left yields the formula n2=S/Fb. Substitute in S=900,000+ 1,600,000+ 3,750,000 =6,250,000, F=750,000,000 and b=1/30,000. The numerical answer is that n=15.8 firms. However, since you will never see .8 firms, there will be 15 firms that enter the market, not 16 firms since the last firm knows that it can not make positive profits. The rest of the solution is straight-forward. Using X=S/n, output per firm is 41,666 units. Using the price equation, and the fact that c=5,000, yields an equilibrium price of $7,000.

5. a. The relatively few locations for production suggest external economies of scale in

production. If these operations are large, there may also be large internal economies of scale in production.

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b. Since economies of scale are significant in airplane production, it tends to be done by a small number of (imperfectly competitive) firms at a limited number of locations. One such location is Seattle, where Boeing produces.

c. Since external economies of scale are significant in semiconductor production, semiconductor industries tend to be concentrated in certain geographic locations. If, for some historical reason, a semiconductor is established in a specific location, the export of semiconductors by that country is due to economies of scale and not comparative advantage.

d. \scotch whiskey can only come from Scotland. The production of scotch whiskey requires a technique known to skilled distillers who are concentrated in the region. Also, soil and climactic conditions are favorable for grains used in local scotch production. This reflects comparative advantage.

e. France has a particular blend of climactic conditions and land that is difficult to reproduce elsewhere. This generates a comparative advantage in wine production.

6. The Japanese producers are price discriminating across United States and Japanese

markets, so that the goods sold in the United States are much cheaper than those sold in Japan. It may be profitable for other Japanese to purchase these goods in the United States, incur any tariffs and transportation costs, and resell the goods in Japan. Clearly,

the price differential across markets must be non-trivial for this to be profitable.

7. a. Suppose two countries that can produce a good are subject to forward-falling supply

curves and are identical countries with identical curves. If one country starts out as a producer of a good, i.e. it has a head start even as a matter of historical accident, then all production will occur in that particular country and it will export to the rest of the world.

b. Consumers in both countries will pay a lower price for this good when external economies are maximized through trade and all production is located in a single

market. In the present example, no single country has a natural cost advantage or is worse off than it would be under autarky. 8.

External economies are important for firms as technology changes rapidly and as the “cutting edge” moves quickly with frequent innovations. As this process slows, manufacturing becomes more routine and there is less advantage conferred by external economies. Instead, firms look for low cost production locations. Since external

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economies are no longer important, firms find little advantage in being clustered and it is likely that locations other than the high-wage original locations are chosen.

FURTHER READINGS

Frank Graham. \Aspects of Protection Further Considered.\Quarterly Journal of Economics 36 (1923) pp.199-227.

Elhanan Helpman and Paul Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. Cambridge: MIT Press, 1985.

Henryk Kierzkowski, ed. Monopolistic Competition and International Trade. Oxford: Clarendon Press, 1984.

Staffan Burenstam Linder. An Essay on Trade and Transformation. New York: John Wiley and Sons, 1961.

Michael Porter. The Competitive Advantage of Nations. New York: Free Press, 1990.

Annalee Saxenian. Regional Advantage. Cambridge: Harvard University Press, 1994.

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economies are no longer important, firms find little advantage in being clustered and it is likely that locations other than the high-wage original locations are chosen.

FURTHER READINGS

Frank Graham. \Aspects of Protection Further Considered.\Quarterly Journal of Economics 36 (1923) pp.199-227.

Elhanan Helpman and Paul Krugman. Market Structure and Foreign Trade: Increasing Returns, Imperfect Competition, and the International Economy. Cambridge: MIT Press, 1985.

Henryk Kierzkowski, ed. Monopolistic Competition and International Trade. Oxford: Clarendon Press, 1984.

Staffan Burenstam Linder. An Essay on Trade and Transformation. New York: John Wiley and Sons, 1961.

Michael Porter. The Competitive Advantage of Nations. New York: Free Press, 1990.

Annalee Saxenian. Regional Advantage. Cambridge: Harvard University Press, 1994.

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