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Specialisation and comparative advantage
Edexcel IAL Economics · WEC14 Developments in the Global Economy
Why do countries trade at all? The theory of comparative advantage shows that two countries can both gain from trade even if one is better at producing everything.
Specialisation and trade
Specialisation is concentrating on producing a limited range of goods. Internationally it lets countries use their resources (climate, skills, natural resources, capital) where they are relatively best, gain economies of scale, and trade for the rest.
Benefits: higher world output, lower prices, wider choice, bigger markets for firms.
Costs: over-dependence on a few products (vulnerable to price falls or changes in demand), structural unemployment when patterns shift, reliance on imports of essentials, and risks from supply chain disruption.
Absolute and comparative advantage
- Absolute advantage: a country can produce more of a good than another with the same resources.
- Comparative advantage: a country can produce a good at a lower opportunity cost than another.
The theory says countries should specialise in the goods where they have a comparative advantage and trade. World output rises and both can consume beyond their own production possibility frontiers (PPFs).
| Output from one unit of resources | Cloth | Wheat | Opportunity cost of 1 wheat |
|---|---|---|---|
| Country A | 20 | 10 | 2 cloth |
| Country B | 12 | 4 | 3 cloth |
Country A has an absolute advantage in both goods
Reading the table
A gives up 2 cloth for each wheat; B gives up 3. So A has the comparative advantage in wheat. For cloth, A gives up 0.5 wheat per cloth and B only 1/3 wheat, so B has the comparative advantage in cloth.
Trade benefits both if the terms of trade lie between the two opportunity costs: between 2 and 3 cloth per wheat.
Diagram in words: draw each country's PPF as a straight line (constant opportunity cost). With trade at a price between the two slopes, each country's consumption possibility line pivots outward beyond its PPF.
Assumptions and limitations
The simple model assumes: two countries and two goods; constant opportunity costs (straight-line PPFs); no transport costs or trade barriers; perfect mobility of factors within a country but none between countries; perfect knowledge; and that the gains are shared through suitable terms of trade.
Limitations: transport costs can wipe out gains; opportunity costs usually rise as a country specialises (diminishing returns); factors are not perfectly mobile, so workers in declining industries lose out; exchange rates and protectionism distort prices; over-specialisation brings risks; comparative advantage can change over time (education and investment create it); and gains may be unevenly distributed between and within countries.
Worked example
Using the table, show that partial specialisation can increase world output. Without trade each country splits its resources equally.
- Without trade: cloth = 10 + 6 = 16; wheat = 5 + 2 = 7
- B specialises fully in cloth: 12 cloth. A makes 8 wheat, which costs 16 cloth, leaving 4 cloth.
- World output: cloth = 16, wheat = 8
Answer: Cloth stays at 16 and wheat rises from 7 to 8: one extra unit of wheat to share.
Check yourself
- Country X can make 30 phones or 10 tablets with one unit of resources. What is the opportunity cost of one tablet in phones?
Show answer
3 phones. 30 / 10 = 3 phones per tablet.
- Country P: 1 unit of resources makes 8 rice or 4 cars. Country Q: 1 unit makes 6 rice or 1 car. Which statement is correct?
- P has a comparative advantage in each of the two goods
- Q has a comparative advantage in cars
- P has a comparative advantage in cars and Q in rice
- Neither country gains from trade
Show answer
P has a comparative advantage in cars and Q in rice. Opportunity cost of a car: P = 2 rice, Q = 6 rice, so P is relatively better at cars; Q gives up only 1/6 car per rice versus 1/2 for P, so Q is relatively better at rice.
- Using P and Q from the previous question, P gains from exporting cars only if it receives more than a certain number of rice per car. What is that number?
Show answer
2 rice. P's own opportunity cost of a car is 8 / 4 = 2 rice, so P needs more than 2 rice per car to gain.
- Country Y can produce 50 units of steel or 20 units of textiles. What is the opportunity cost of 1 unit of steel in textiles? Give your answer to 1 decimal place.
Show answer
0.4 textiles. 20 / 50 = 0.4 textiles per unit of steel.
- A country that can produce more of every good than another with the same resources has
- a comparative advantage in every good
- an absolute advantage in every good
- no reason to trade
- constant returns to scale
Show answer
an absolute advantage in every good. Producing more of everything is absolute advantage; it can still gain by specialising where its comparative advantage lies.
- Explain one limitation of the theory of comparative advantage.
Show answer
Transport costs can be greater than the gains from specialisation, or opportunity costs rise as a country specialises, so the gains are smaller than the model predicts.. Any assumption that does not hold in reality reduces the gains.
- Which is a cost of a country specialising heavily in one export?
- Lower average costs from economies of scale
- Vulnerability to a fall in world demand or price for that good
- Higher world output
- Wider choice for consumers
Show answer
Vulnerability to a fall in world demand or price for that good. Dependence on one product makes export earnings volatile.
Sources
Last updated 8 November 2026. Spotted a mistake? Tell us.