Lesson 1 of 6 · All lessons in this module
Free lesson: the first lesson of every module is open to everyone.
Lesson 1 of 6 · 13 min
Why countries trade: the benefits
Trade lets each country specialise in what it does relatively cheaply, sell into bigger markets and face more competition, so the world as a whole consumes more than it could in isolation.
In short
- Gains from exchange: exporters get a higher price than at home and importers pay less than it would cost to make the good themselves.
- Comparative advantage: a country gains by specialising in the good with the lowest opportunity cost, even if it is not the cheapest producer of anything in absolute terms.
- Traditional models explain comparative advantage by technology differences (Ricardian) and factor endowment differences (Heckscher-Ohlin).
- Newer models stress economies of scale, greater product variety and more competition, which also explain intra-industry trade between similar countries.
- Trade can raise real GDP through better resource allocation, learning by doing, knowledge spillovers and better institutions.
- Overall welfare rises, but not everyone gains: the winners could compensate the losers and still be better off.
Gains from exchange and specialisation
Without trade, a country must make everything it consumes. With trade, it can sell goods it makes cheaply at the higher world price and buy goods it makes expensively at the lower world price. That is the gain from exchange.
Exchange then reshapes production. Each country makes more of its export good and less of its import good, moving resources to where they are most productive. This more efficient allocation of resources lets every country consume a bigger bundle of goods than it could produce alone.
The key idea is comparative advantage: what matters is the opportunity cost of a good, meaning how much of another good you give up to make it. A country exports the good whose opportunity cost is lower than abroad, even if another country is better at making everything.
Comparative, not absolute: even a country that is the most efficient producer of everything gains by focusing on what it is *relatively* best at and importing the rest.
Where comparative advantage comes from
Traditional trade theory offers two sources. In the Ricardian model, countries differ in technology (labour productivity), so opportunity costs differ. In the Heckscher-Ohlin model, countries differ in factor endowments: a capital-rich country exports capital-intensive goods and a labour-rich country exports labour-intensive goods.
Both models predict trade between different countries, each specialising in different industries. They do not explain why similar rich countries exchange huge volumes of the same kinds of goods, such as cars, machinery or wine. That needs newer models.
| Traditional models | Newer models | |
|---|---|---|
| Source of gains | Comparative advantage (technology or factor endowments) | Economies of scale, product variety, competition |
| Typical trade | Different goods between different countries | Similar goods between similar countries (intra-industry) |
| Examples | Ricardian; Heckscher-Ohlin | Increasing returns; monopolistic competition |
Scale, variety and competition
In industries with increasing returns to scale (cars, steel, aircraft), average cost falls as output rises. A firm selling only to its home market stays small; opening to trade gives it a larger market, a larger output and a lower average cost.
Monopolistically competitive industries have many firms, each selling a differentiated product, with free entry and exit and zero long-run economic profit. When two similar countries trade, each focuses on certain varieties and imports others. The result is intra-industry trade: a country both exports and imports goods in the same product category, such as German and French firms selling each other different car models.
Consumers gain from greater product variety, and firms gain from scale economies because they sell into both markets. Foreign competition also reduces the monopoly power of domestic firms and forces them to become more efficient than they would be in a closed economy.
Trade and growth
Research suggests that opening to trade tends to raise real GDP, although economists still debate how strong the link is. The channels go beyond static efficiency.
In learning-by-doing industries such as semiconductors, unit cost falls as cumulative output and experience grow, so a bigger market speeds up the learning. Trade also spreads ideas: technical know-how flows more freely, firms learn foreign tastes, and foreign R&D spills over into domestic productivity, more so the more open the economy is.
Finally, openness can push governments toward better institutions and policies that reward innovation. A firm may even relocate production to a trading partner with skilled workers and strong suppliers so that it can win global contracts.
- Gains from exchange and specialisation (comparative advantage)
- Economies of scale from a larger market
- Greater variety of goods for households and firms
- More competition, less monopoly power, more efficiency
- More efficient allocation of resources, plus learning, spillovers and better institutions
"Gains from trade" means total benefits exceed total losses. It does not mean every producer, consumer and worker benefits equally, or at all.
Worked examples
Example 1 Who has the comparative advantage?
Suppose Norway can produce 1 ton of salmon by giving up 2 tons of wheat, while Chile must give up 5 tons of wheat for 1 ton of salmon. Which country should export salmon, and is a trade price of 3 tons of wheat per ton of salmon good for both?
Example 2 Economies of scale from a bigger market
A Korean carmaker has fixed costs of USD 1 million and a variable cost of USD 20 per unit. At home it sells 50,000 units. After a trade agreement it sells 200,000 units. What happens to average cost?
Example 3 Explaining two-way trade
Italy and France are similar high-income economies with similar technology and capital per worker. Yet each imports billions of euros of cheese from the other. Which theory explains this best?
On the exam
Expect items listing the benefits of trade (exchange and specialisation, scale, variety, competition, efficient allocation), the meaning of 'gains from trade', and which model explains intra-industry trade.
- Thinking trade benefits every individual. Overall welfare rises, but some producers and workers lose; the winners could compensate the losers.
- Confusing absolute and comparative advantage. Trade follows opportunity cost, not who is the cheapest producer in absolute terms.
- Saying countries gain by receiving lower prices for exports. Trade lets them sell exports at higher prices and buy imports at lower prices.
- Attributing intra-industry trade to Heckscher-Ohlin. It is explained by economies of scale and product differentiation.
Check yourself
Q1Which statement best describes a benefit of international trade?
Q2Producing 1 ton of steel costs Japan 4 tons of rice and India 6 tons of rice. Which country has the comparative advantage in rice?
Q3Sweden both exports and imports trucks. This pattern is best explained by:
Q4A firm's fixed costs are EUR 600,000 and variable cost is EUR 10 per unit. Raising output from 30,000 to 120,000 units through exports lowers average cost to closest to:
Q5The statement that trade produces overall 'gains from trade' most accurately means:
Q6Which channel is least likely to explain why trade can raise real GDP?
Answer the 6 questions: +10 XP for each one you get right first time.
Liked this lesson? Get the rest free for 7 days
Create a free account to open the other 5 lessons in this module, with videos, flashcards that come back before you forget them, the question bank and full mocks. No card needed.