The Advantage

The person who does everything better may still have something to gain from exchange. The observation sounds like a courtesy paid to the less accomplished until the comparison is made carefully. A skilled maker can be quicker at both cloth and wine, yet the time spent making cloth is time that cannot be spent making wine. Another maker, slower at each task, may give up less wine for a piece of cloth. The relevant difference then lies in what each must forgo, rather than in who finishes first. Comparative advantage gives that difference a name. It explains how specialization can enlarge the possibilities open to both parties even when one has an absolute advantage in every activity. The surplus comes from arranging the work so that what is sacrificed to obtain the desired goods is smaller. A ranking of talents, by itself, cannot tell us how the work should be divided.

Ricardo gave the argument its enduring form with English cloth and Portuguese wine. Producing a specified quantity of cloth might require the labor of a hundred men for a year in England, while producing a specified quantity of wine required a hundred and twenty. In Portugal the corresponding requirements were ninety for cloth and eighty for wine. Portugal was more productive in both. But England sacrificed only five-sixths of a unit of wine to make a unit of cloth: the hundred units of labor used for cloth would otherwise produce a hundred divided by a hundred and twenty units of wine. Portugal sacrificed nine-eighths of a unit of wine for the same cloth. England therefore had the lower opportunity cost in cloth, while Portugal had the lower opportunity cost in wine. These ratios compare alternative uses of labor within each country. They do not require treating an hour of English work as identical in productive power to an hour of Portuguese work; the whole point is that their productive possibilities differ.¹

At an exchange of one unit of cloth for one unit of wine, both countries can obtain an import with less labor than it would take to make that import at home. England makes cloth with a hundred units of labor and exchanges it for wine that would have required a hundred and twenty. Portugal makes wine with eighty and exchanges it for cloth that would have required ninety. England saves twenty of its own labor units; Portugal saves ten of its own. The numerical gains are local comparisons, not an interpersonal sum of satisfaction. Nor is one-for-one the only rate that permits them. Measured in wine per unit of cloth, any rate strictly between five-sixths and nine-eighths gives both a production-cost advantage in the specified exchange. Near one end England keeps little of the opportunity; near the other Portugal does. The technologies delimit a range of mutually advantageous terms, while leaving a question about which terms the bargain or market will actually produce. The creation of the gain and its division are already separate.²

The argument concerns productive alternatives under a particular arrangement of resources. Labor can move between the two activities within each country in the simplified example, while the productive agents do not simply migrate to whichever country has the highest absolute productivity. Ricardo makes this boundary explicit. If capital and labor could freely relocate to Portugal under his stipulated conditions, the question would change: both goods might be made there. The familiar comparative-cost calculation instead asks how countries can exchange the products of resources that remain within them. Given suitable demand, the relative costs provide a reason to specialize and trade. They do not by themselves specify how much cloth anyone wants, how large the countries are, or which of them will specialize completely at the resulting world price. Those further conditions determine the scale and final pattern of production. The two-country example establishes a possibility that an absolute productivity ranking would miss; it does not turn four labor requirements into a complete description of an international economy.³

Costs of making the exchange can consume part or all of the advantage. If obtaining the wine through export requires England to devote another five of its labor units to transport and handling, its saving in the illustrative exchange falls from twenty to fifteen. If that additional real requirement reaches twenty, the production saving has been exhausted. The same comparison must be made on the other side, and quality, timing and reliability must remain comparable. This is why a difference in relative production costs need not produce an observed trade. The resources may be needed in another use, the goods may be costly to move, or a temporary transition may require skills and equipment that cannot be rearranged without loss. The calculation also does not make a country's gain identical to every resident's gain. A worker or owner tied to the activity that contracts can face a worse alternative even while other people obtain more goods. An enlarged opportunity for the country is a claim about what becomes feasible; showing how particular people share in it requires an account of their incomes, adjustments and institutions.⁴

Comparative advantage is a relation that can change. A better process, a new skill or a change in the available resources alters what a country must surrender to make a good. Ricardo himself goes on to consider an improvement in English wine production that changes the previous basis of exchange. The lesson cannot be that a country should preserve forever the activity in which it happened to have the lower relative cost at one date. Nor does the comparison establish that every change abroad improves the opportunities available at home. It asks what the alternatives are under the conditions being examined, and those conditions must be examined again when they change. There is a similar boundary around its welfare meaning. A calculation that omits an injury to a neighbor, or counts a scarce resource at an artificial price, has not measured the full sacrifice involved. The strength of the principle lies in directing attention to that sacrifice. Its practical use depends on specifying it well, rather than treating an existing pattern of specialization as its own justification.⁵

The advantage is a comparison between the alternatives each gives up. That comparison can make cooperation productive across an absolute inequality of skill, and it can expose a gain that looking at each task in isolation would conceal. Yet the very range of terms that permits both parties to benefit returns us to the volume's governing question. A gain can exist without determining who keeps most of it. Technology helps mark the possibilities; demand, bargaining and institutions help select among them. The price that emerges is therefore doing more than recording the fact that exchange was worthwhile. It is dividing what the exchange made available. The next plate, The Bidding, makes the institution visible. When a seller invites offers under an announced rule, the rule helps decide both who receives the good and how much of the advantage remains with the winner.