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IB DP Economics — Unit 4: The Global Economy | SL | 4.1 Benefits of International Trade
📋 What You Will Learn
- Identify the key benefits of international trade including specialisation, lower prices, and increased variety
- Explain the principle of comparative advantage and how it justifies free trade between nations
- Analyse the gains from trade using free trade diagrams showing consumer surplus, producer surplus, and welfare effects
- Apply free trade diagrams to show the impact of opening a domestic market to international trade
- Evaluate the limitations of comparative advantage as a basis for free trade policy
🔍 Guiding Question Does free trade always make countries better off — and if so, why do governments so frequently restrict it?
🌍 Why This Matters In 2023, global merchandise trade reached approximately $24 trillion, with services trade adding a further $7 trillion — yet political pressure to restrict trade has never been stronger. The United States imposed sweeping tariffs on Chinese goods, the EU debated carbon border taxes, and India restricted rice exports. Understanding why free trade generates gains — and who wins and who loses — is essential for analysing every major policy debate in the global economy.
1. What Is International Trade?
Countries trade because they cannot produce everything they need efficiently, or because other countries can produce certain goods at lower cost. International trade is the exchange of goods and services across national borders, and it is one of the most powerful forces shaping living standards worldwide.
📖 Definition — International Trade International trade refers to the exchange of goods and services between countries. Exports are goods and services sold to foreign buyers; imports are goods and services purchased from foreign sellers.
- Exports: goods and services produced domestically and sold abroad — a source of income for the domestic economy
- Imports: goods and services produced abroad and purchased domestically — a source of supply for domestic consumers
- Free trade: international trade conducted without government-imposed barriers such as tariffs, quotas, or subsidies
- Trade occurs because countries differ in their productive capabilities — some can produce certain goods more efficiently than others
2. Absolute and Comparative Advantage
The most important theoretical foundation for free trade is the principle of comparative advantage. It explains why trade is mutually beneficial even when one country is more efficient at producing everything.
📖 Definition — Absolute Advantage A country has an absolute advantage in the production of a good if it can produce more of that good than another country using the same quantity of resources, or produce the same quantity using fewer resources.
📖 Definition — Comparative Advantage A country has a comparative advantage in the production of a good if it can produce that good at a lower opportunity cost than another country. Countries should specialise in and export goods in which they have a comparative advantage, and import goods in which they have a comparative disadvantage.
🔗 Analogy — The Lawyer and the Secretary Suppose a lawyer is both a better lawyer and a faster typist than their secretary. Should the lawyer type their own letters? No — the lawyer's opportunity cost of typing is enormous (lost