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6.1 Chapter Overview

Learning Objective

  1. Learn the basic rationale for economies-of-scale models with international trade.

Another major reason that international trade may take place is the existence of economies of scale (also called increasing returns to scale) in production. Economies of scaleThe feature of many production processes in which the per-unit cost of producing a product falls as the scale of production rises. means that production at a larger scale (more output) can be achieved at a lower cost (i.e., with economies or savings). When production within an industry has this characteristic, specialization and trade can result in improvements in world productive efficiency and welfare benefits that accrue to all trading countries.

Trade between countries need not depend on country differences under the assumption of economies of scale. Indeed, it is conceivable that countries could be identical in all respects and yet find it advantageous to trade. For this reason, economies-of-scale models are often used to explain trade among countries like the United States, Japan, and the European Union. For the most part, these countries, and other developed countries, have similar technologies, similar endowments, and to some extent similar preferences. Using classical models of trade (e.g., Ricardian, Heckscher-Ohlin), these countries would have little reason to engage in trade. Yet trade between the developed countries makes up a significant share of world trade. Economies of scale can provide an answer for this type of trade.

Another feature of international trade that remains unexplained with classical models is the phenomenon of intraindustry trade. A quick look at the aggregate trade data reveals that many countries export and import similar products. For example, the United States imports and exports automobiles, imports and exports machine tools, imports and exports steel, and so on. To some extent, intraindustry trade arises because many different types of products are aggregated into one category. For example, many different types of steel are produced, from flat-rolled to specialty steels. It may be that production of some types of steel requires certain resources or technologies in which one country has a comparative advantage. Another country may have the comparative advantage in another type of steel. However, since all these types are generally aggregated into one export or import category, it could appear as if the countries are exporting and importing “identical” products when in actuality they are exporting one type of steel and importing another type.

Nevertheless, it is possible to explain intraindustry trade in a model that includes economies of scale and differentiated products even when there are no differences in resources or technologies across countries. This model is called the monopolistic competition model. Its focus is on consumer demand for a variety of characteristics embodied in the goods sold in a product category. In this model, advantageous trade in differentiated products can occur even when countries are very similar in their productive capacities.

Key Takeaways

  • The presence of economies of scale in production represents another reason countries may trade with each other.
  • Economies-of-scale models are used to explain intraindustry trade—that is, trade between countries with similar characteristics, like the United States and Canada.


  1. Jeopardy Questions. As in the popular television game show, you are given an answer to a question and you must respond with the question. For example, if the answer is “a tax on imports,” then the correct question is “What is a tariff?”

    1. The term used to describe when both exports and imports of a good occur in the same industry.
    2. The term used to describe production in which the unit cost falls as the size of the industry becomes larger.
    3. Models incorporating this assumption about production are used to explain trade between countries with similar characteristics.