普格尔《国际贸易（第17版）》 英文手册Pugel_17e_chap003_IM.docxVIP

PAGE PAGE 21 ? 2016 by McGraw-Hill Education. ?This is proprietary material solely for authorized instructor use. Not authorized for sale or distribution in any manner. ?This document may not be copied, scanned, duplicated, forwarded, distributed, or posted on a website, in whole or part.? Chapter 3 Why Everybody Trades: Comparative Advantage Overview This chapter extends the analysis of international trade to consider trade in a multiple-product economy. An economy composed of two products is useful to bring out insights about international trade. This general equilibrium approach explicitly shows the effects of resource reallocations between industries. The chapter culminates in showing the importance of comparative advantage for understanding why countries trade. The story begins with Adam Smith and absolute advantage. (A box on mercantilism summarizes the view that Smith opposed and shows how mercantilist thinking continues today.) The analysis focuses on the productivity of labor (output per hour) in producing each of two products (wheat and cloth) in two countries (the United States and the rest of the world). Smith examined the case of absolute advantage, in which labor productivity in producing one product is higher in one country and labor productivity in producing the other product is higher in the other country. With no trade each country must produce both products to meet national demands. The discussion of the Smith case focuses on the increase in global production efficiency achieved by shifting production in each country toward the product in which it has the higher labor productivity. National demands can be met by international trade—apparently excess supplies can be exported and apparently excess demands can be met by imports. The increase in total world production is the evidence of gains from international trade. Smiths approach does not indicate what would happen if the same country has absolute advantage in both products. Ricardo took u