Skip to main content
Social Sci LibreTexts

17.1: The Gains from Trade

  • Page ID
    14129
  • Learning Objectives

    1. Differentiate between an absolute advantage in producing some good and a comparative advantage.
    2. Explain and illustrate the conditions under which two countries can mutually benefit from trading with each other.
    3. Explain and illustrate how the terms of trade determine the extent to which each country specializes.
    4. Explain and illustrate the mutual benefits of trade.

    To model the effects of trade, we begin by looking at a hypothetical country that does not engage in trade and then see how its production and consumption change when it does engage in trade.

    Production and Consumption Without International Trade

    Suppose the hypothetical country of Roadway is completely isolated from the rest of the world. It neither exports nor imports goods and services. We shall use the production possibilities model to analyze Roadway’s ability to produce goods and services.

    A production possibilities curve illustrates the production choices available to an economy. Recall that the production possibilities curve for a particular country is determined by the factors of production and the technology available to it.

    Figure 17.1 “Roadway’s Production Possibilities Curve” shows a production possibilities curve for Roadway. We assume that it produces only two goods—trucks and boats. Roadway must be operating somewhere on its production possibilities curve or it will be wasting resources or engaging in inefficient production. If it were operating inside the curve at a point such as D, then a combination on the curve, such as B, would provide more of both goods (Roadway produces 3,000 more trucks and 3,000 more boats per year at B than at D). At any point inside the curve, Roadway’s production would not be efficient. Point E suggests an even higher level of output than points A, B, or C, but because point E lies outside Roadway’s production possibilities curve, it cannot be attained.

    Figure 17.1 Roadway’s Production Possibilities Curve

    300cca1a52f6678fc27059f289cebe01.jpg

    The production possibilities curve for Roadway shows the combinations of trucks and boats that it can produce, given the factors of production and technology available to it. To maximize the value of total production, Roadway must be operating somewhere along this curve. Production at point D implies that Roadway is failing to use its resources fully and efficiently; production at point E is unobtainable.

    We have learned that the absolute value of the slope of a production possibilities curve at any point gives the quantity of the good on the vertical axis that must be given up to produce an additional unit of the good on the horizontal axis. It thus gives the opportunity cost of producing another unit of the good on the horizontal axis.

    Figure 17.2 Measuring Opportunity Cost in Roadway

    1bfcf0bf37420459433ba563e6212a12.jpg

    The slope of the production possibilities curve at any point is equal to the slope of a line tangent to the curve at that point. The absolute value of the slope equals the opportunity cost of increased boat production. Moving down and to the right along its production possibilities curve, the opportunity cost of boat production increases; this is an application of the law of increasing opportunity cost.

    Figure 17.2 “Measuring Opportunity Cost in Roadway” shows the opportunity cost of producing boats at points A, B, and C. Recall that the slope of a curve at any point is equal to the slope of a line drawn tangent to the curve at that point. The slope of a line tangent to the production possibilities curve at point B, for example, is −1. The opportunity cost of producing one more boat is thus one truck. As the law of increasing opportunity costs predicts, in order to produce more boats, Roadway must give up more and more trucks for each additional boat. Roadway’s opportunity cost of producing boats increases as we travel down and to the right on its production possibilities curve.

    Comparative Advantage

    People participate in international trade because they make themselves better off by doing so. In this section we will find that countries that participate in international trade are able to consume more of all goods and services than they could consume while producing in isolation from the rest of the world.

    Suppose the world consists of two countries, Roadway and Seaside. Their production possibilities curves are given in Figure 17.3 “Comparative Advantage in Roadway and Seaside”. Roadway’s production possibilities curve in Panel (a) is the same as the one in Figure 17.1 “Roadway’s Production Possibilities Curve” and Figure 17.2 “Measuring Opportunity Cost in Roadway”. Seaside’s curve is given in Panel (b).

    Figure 17.3 Comparative Advantage in Roadway and Seaside

    8740d4af04712870b949185bbdd05a4e.jpg

    Roadway’s production possibilities curve is given in Panel (a); it is the same one we saw in Figure 17.1 “Roadway’s Production Possibilities Curve” and Figure 17.2 “Measuring Opportunity Cost in Roadway”. The production possibilities curve for a second hypothetical country, Seaside, is given in Panel (b). If no trade occurs between the two countries, suppose that Roadway is at Point A and that Seaside is at Point A′. Notice that the opportunity cost of an additional boat in Roadway is two trucks, while the opportunity cost of an additional boat in Seaside is 0.2 trucks. Clearly, Seaside has a comparative advantage in the production of boats.

    Each country produces two goods, boats and trucks. Suppose no trade occurs between the two countries and that they are each currently operating on their production possibilities curves at points A and A′ in Figure 17.3 “Comparative Advantage in Roadway and Seaside”. We will assume that the two countries have chosen to operate at these points through the workings of demand and supply. That is, resources have been guided to their current uses as producers have responded to the demands of consumers in the two countries. In turn, consumers have responded to the prices charged by sellers of boats and trucks.

    The two countries differ in their respective abilities to produce trucks and boats. As we can see by looking at the intersection of the production possibilities curves with the vertical axes in Figure 17.3 “Comparative Advantage in Roadway and Seaside”, Roadway is able to produce more trucks than Seaside. If Roadway concentrated all of its resources on the production of trucks, it could produce 10,000 trucks per year. Seaside could produce only 5,000. Now look at the intersection of the production possibilities curves with the horizontal axes. If Roadway concentrated all of its resources on the production of boats, it could produce 10,000 boats. Seaside could produce only 7,000 boats. Because Roadway is capable of producing more of both goods, we can infer that it has more resources or is able to use its labor and capital resources more productively than Seaside. When an economy or individual can produce more of any good per unit of labor than another country or individual, that country or person is said to have an absolute advantage.

    Despite the fact that Roadway can produce more of both goods, it can still gain from trade with Seaside—and Seaside can gain from trade with Roadway. The key lies in the opportunity costs of the two goods in the two countries. The country with a lower opportunity cost for a particular good or service has a comparative advantage in producing it and will export it to the other country.

    We can determine opportunity costs in the two countries by comparing the slopes of their respective production possibilities curves at the points where they are producing. At point A in Panel (a) of Figure 17.3 “Comparative Advantage in Roadway and Seaside”, one additional boat costs two trucks in Roadway; that is its opportunity cost. At point A′ in Panel (b), 1 additional boat in Seaside costs only 0.2 truck. Alternatively, we can ask about the opportunity cost of an additional truck. In Roadway, an additional truck costs 0.5 boats. In Seaside, it costs five boats. Roadway thus has a comparative advantage in producing trucks; Seaside has a comparative advantage in producing boats. This situation is suggested pictorially in Figure 17.4 “A Picture of Comparative Advantage in Roadway and Seaside”.

    Figure 17.4 A Picture of Comparative Advantage in Roadway and Seaside

    b3249c531ad99aec30c8c8c3ae74180c.jpg

    The exhibit gives a picture of Roadway’s comparative advantage in trucks and Seaside’s comparative advantage in boats.