Why Nations Trade

Explore comparative advantage and the gains from trade.

  • Define and explain Why Nations Trade in your own words
  • Use key terms such as comparative advantage accurately
  • Apply what you have learned to new examples and questions
  • Avoid the common mistakes learners make with this topic

No country makes everything it needs — trade lets nations specialise while consumers enjoy goods from around the world. This chapter explains why countries trade, how exchange rates work, why governments sometimes restrict trade, and what globalisation means for development.

This lesson focuses on Why Nations Trade: explore comparative advantage and the gains from trade.

Definition: Why Nations Trade

Explore comparative advantage and the gains from trade.

Key ideas

The gains from trade

Ricardo showed that if Portugal gives up less wine to make cloth than England does, both gain by specialising and trading — even if Portugal is better at both. Trade enlarges both nations' consumption possibilities, though the gains may be unevenly shared within each country.

Protectionism versus free trade

Tariffs and quotas shield domestic jobs and infant industries and can protect national security, but they raise consumer prices, invite retaliation and shelter inefficiency. Globalisation has lifted millions from poverty through trade-led growth, yet created losers in declining industries — hence demands for retraining and compensation.

Key term — comparative advantage: Ricardo's principle that countries gain by specialising in what they produce at the lowest opportunity cost — even if another country is more efficient at everything.

Worked example: Why Nations Trade

State Ricardo's principle of comparative advantage.

Countries gain by specialising in goods they produce at the lowest opportunity cost, then trading.

Answer: Countries gain by specialising in goods they produce at the lowest opportunity cost, then trading.

Common mistakes
  • Assuming trade benefits everyone equally Trade creates aggregate gains but also displaced workers and regions — distribution matters as much as efficiency.
  • Thinking exports are good and imports bad Imports give consumers choice and lower prices and supply inputs for exporters — a surplus is not automatically better than a deficit.

Practice

Give one argument for and one against tariffs.
Jobs vs prices.

For: protects domestic jobs and infant industries. Against: raises consumer prices and risks retaliation.

If £1 = $1.27, how many dollars does £50 buy?
Multiply.

$63.50 (50 × 1.27).

The pound depreciates. What happens to the price of UK exports abroad?
Cheaper or dearer?

They become cheaper in foreign currency, boosting demand for them.

What is a quota?
A limit, not a tax.

A physical limit on the quantity of a good that may be imported.

Quick check

Why Nations Trade — quick check

Which of these best defines "comparative advantage"?

Ricardo's principle that countries gain by specialising in what they produce at the lowest opportunity cost — even if another country is more efficient at everything.

Why might globalisation increase inequality within a country?

Workers in industries exposed to import competition may lose jobs and wages, while skilled workers and consumers gain.
Key takeaways
  • Why Nations Trade: explore comparative advantage and the gains from trade.
  • The gains from trade: Ricardo showed that if Portugal gives up less wine to make cloth than England does, both gain by specialising and trading — even if Portugal is better at both.
  • current account: The record of a country's trade in goods and services plus investment income.
  • Watch out for: assuming trade benefits everyone equally