How do I explain comparative advantage with a numerical example?
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The question
My economics assignment asks me to explain comparative advantage with a numerical example.
I keep mixing up comparative advantage and absolute advantage.
Short answer
Comparative advantage depends on lower opportunity cost, not absolute productivity. A strong answer calculates opportunity costs, identifies who should specialise in each good, and explains how trade can make both sides better off.
Full expert answer
Economics tutor
MSc Economics
Comparative advantage is one of the most important ideas in international trade. It says that countries, firms or people can gain from trade when they specialise in the activity where their opportunity cost is lowest.
What the question is asking
The question is asking you to calculate opportunity cost and use it to decide specialisation. It is not enough to say one country produces more of everything. That is absolute advantage, not comparative advantage.
Mini numerical example
In one day:
| Country | Wheat | Cloth |
|---|---|---|
| A | 10 | 5 |
| B | 6 | 4 |
Country A has absolute advantage in both goods because it can produce more wheat and more cloth. But comparative advantage depends on opportunity cost.
For A:
- 10 wheat = 5 cloth
- 1 wheat costs 0.5 cloth
- 1 cloth costs 2 wheat
For B:
- 6 wheat = 4 cloth
- 1 wheat costs 0.67 cloth
- 1 cloth costs 1.5 wheat
A has lower opportunity cost in wheat. B has lower opportunity cost in cloth. So A should specialise more in wheat and B more in cloth.
Sample questions and short answers
1. Can one country have absolute advantage in both goods?
Yes. But it cannot have comparative advantage in both goods if opportunity costs differ.
2. What determines comparative advantage?
Lower opportunity cost.
3. Why does trade help?
Specialisation and exchange can allow both sides to consume beyond what they could produce alone.
4. What should I draw?
A production possibility frontier can show the trade-off and gains from specialisation.
Common student mistakes
- Using output numbers without calculating opportunity cost
- Confusing absolute and comparative advantage
- Forgetting units
- Not explaining gains from trade
- Assuming trade benefits are automatic without conditions
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Academic use note
Use this example to learn the method. Apply the same opportunity-cost logic to the numbers in your own assignment.
Sources and further reading
This answer explains a method for you to apply to your own work. Copying it into a submission would count as plagiarism, and it is indexed by similarity checkers.
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