The Theory of Comparative Advantage
The Theory of Comparative Advantage

It seems obvious that if one country is better at producing one good and another country is better at producing a different good (assuming both countries demand both goods) that they should trade. What happens if one country is better at producing both goods? Should the two countries still trade? This question brings into play the theory of comparative advantage and opportunity costs.

The everyday choices that we make are, without exception, made at the expense of pursuing one or several other choices. When you decide what to wear, what to eat for dinner, or what to do on Saturday night, you are making a choice that denies you the opportunity to explore other options.

The same holds true for individuals or companies producing goods and services. In economic terms, the amount of the good or service that is sacrificed in order to produce another good or service is known as opportunity cost. For example, suppose Switzerland can produce either one pound of cheese or two pounds of chocolate in an hour. If it chooses to produce a pound of cheese in a given hour, it forgoes the opportunity to produce two pounds of chocolate. The two pounds of chocolate, therefore, are the opportunity cost of producing the pound of cheese. They sacrificed two pounds of chocolate to make one pound of cheese.

A country is said to have a comparative advantage in whichever good has the lowest opportunity cost. That is, it has a comparative advantage in whichever good it sacrifices the least to produce. In the example above, Switzerland has a comparative advantage in the production of chocolate. By spending one hour producing two pounds of chocolate, it gives up producing one pound of cheese, whereas, if it spends that hour producing cheese, it gives up two pounds of chocolate.

Thus, the good in which a comparative advantage is held is the good that the country produces most efficiently (for Switzerland, its chocolate). Therefore, if given a choice between producing two goods (or services), a country will make the most efficient use of its resources by producing the good with the lowest opportunity cost, the good for which it holds the comparative advantage. The country can trade with other countries to get the goods it did not produce (Switzerland can buy cheese from someone else).

The concepts of opportunity cost and comparative advantage are tricky and best studied by example:  consider a world in which only two countries exist (Italy and China) and only two goods exist (shirts and bicycles). The Chinese are very efficient in producing both goods. They can produce a shirt in one hour and a bicycle in two hours. The Italians, on the other hand, are not very productive at manufacturing either good. It takes them three hours to produce one shirt and five hours to produce one bicycle.

China

SHIRTS BICYCLES
Number of Hours to Produce One Unit 1 2
Opportunity Cost (of producing one unit) ½ bicycle 2 shirts

Italy

SHIRTS BICYCLES
Number of Hours to Produce One Unit 3 5
Opportunity Cost (of producing one unit) 3/5 bicycle 5/3 shirts

The Chinese have a comparative advantage in shirt manufacturing, as they have the lowest opportunity cost (1/2 bicycle) in that good. Likewise, the Italians have a comparative advantage in bicycle manufacturing as they have the lowest opportunity cost (5/3 shirts) in that good. It follows, then, that the Chinese should specialize in the production of shirts and the Italians should specialize in the production of bicycles, as these are the goods that both are most efficient at producing. The two countries should then trade their surplus products for goods that they cannot produce as efficiently.

Comparative advantage not only affects the production decisions of trading nations, but it also affects the prices of the goods involved. After trade, the world market price (the price an international consumer must pay to purchase a good) of both goods will fall between the opportunity costs of both countries. For example, the world price of a bicycle will be between 5/3 shirt and 2 shirts, thereby decreasing the price the Italians pay for a shirt while allowing the Italians to profit. The Chinese will pay less for a bicycle and the Italians less for a shirt than they would pay if the two countries were manufacturing both goods for themselves.

 

Next: Comparative Advantags vs. Absolute Advantage