What Is Comparative Advantage?
Absolute advantage means producing more with the same resources. Comparative advantage means producing at a lower opportunity cost, the alternative output given up. A country can have absolute advantage in both goods yet still gain by specialising where its relative advantage is greater.
Builds on: How Do World Prices Determine Imports and Exports?
What you will learn
- Absolute advantage compares output with equal resources; comparative advantage compares sacrificed alternatives.
- Evaluate who gains from international trade
Essential definitions
- Imports
- Goods and services purchased from abroad.
- Exports
- Goods and services sold abroad.
- Autarky
- An economy without international trade.
- Absolute advantage
- The ability to produce more output with the same resources.
- Comparative advantage
- The ability to produce a good at a lower opportunity cost.
- Opportunity cost
- The next-best alternative given up when a choice is made; here, the output of the other good forgone.
Compare productivity and sacrifice
Absolute advantage means producing more with the same resources. Comparative advantage means producing at a lower opportunity cost, the alternative output given up. A country can have absolute advantage in both goods yet still gain by specialising where its relative advantage is greater.
Suppose equal resources let A produce either 40 wheat or 20 cloth, while B can produce 30 wheat or 30 cloth. A produces more wheat; B produces more cloth. To identify comparative advantage, compare what each sacrifices, not simply their maximum output.
Calculate one good in units of the other
For a linear frontier, opportunity cost of one wheat = maximum cloth ÷ maximum wheat. A gives up 20 ÷ 40 = 0.5 cloth per wheat; B gives up 30 ÷ 30 = 1 cloth. A therefore has comparative advantage in wheat. In cloth, A gives up 2 wheat per cloth while B gives up 1, so B has comparative advantage in cloth.
Different relative costs create a reason to specialise and exchange. Identical costs leave no such gain in this two-good model. Resources, climate, skills, technology and institutions help explain differences, but education and investment can change them. Globalisation means growing cross-border links, of which trade is one part. The next lesson checks a mutually useful trading price and feasible consumption bundles rather than assuming any exchange makes both countries better off.
Hypothetical productivity comparison
- With equal resources, A can produce 40 wheat or 20 cloth; B can produce 30 wheat or 30 cloth.
- A produces more wheat, while B produces more cloth. A gives up 0.5 cloth for each wheat; B gives up 1 cloth.
- A has comparative advantage in wheat; B gives up only 1 wheat per cloth versus A’s 2.
Comparative advantage depends on relative opportunity costs, and B has comparative advantage in cloth.
Apply and evaluate
- The simple model assumes resources can move between industries; actual skills and locations can slow adjustment.
- Competition and scale benefits depend on market access and institutions, while environmental costs may remain unpriced.
Common misconceptions
- Absolute advantage in both goods does not rule out gains from trade.
- National gains do not mean every domestic producer or worker gains.
Knowledge check
If A is absolutely more productive in both goods, can B still have comparative advantage?
What to remember
Absolute advantage compares output with equal resources; comparative advantage compares sacrificed alternatives. Different opportunity costs can support trade even when one country is more productive at both goods.
Completion records your reflection, not a test score.
Lessons in this section
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