Ch11. International Trade Theory — Comparative Advantage, Trade Policy, and the Economics of Exchange Rates

Why Does International Trade Occur?

The fundamental reason nations trade is differences in productive efficiency. Producing every good domestically is less beneficial than concentrating on what you do well and exchanging with others.

Benefits of free trade:

Consumers: access to a wider variety of goods at lower prices
Producers: larger markets enabling economies of scale
Nations overall: more efficient resource allocation

Comparative Advantage: The Ricardian Model

Absolute Advantage: The ability to produce a given quantity using fewer resources

Comparative Advantage: Specialization in goods where opportunity cost is relatively lower

Example: Output producible per hour of work in two countries

          | Rice | Computers
----------|------|----------
Country A |  2   |    1
Country B | 10   |    3

Country A: 1 unit of rice = 0.5 computers (opportunity cost)
Country B: 1 unit of rice = 0.3 computers (opportunity cost)

→ Country B has comparative advantage in rice
→ Country A has comparative advantage in computers

Gains from trade: When both countries specialize in their comparative advantage good, the range of consumption combinations available to each expands beyond pre-trade possibilities.

The Heckscher-Ohlin (H-O) Theorem

An extension of the Ricardian model — the factor endowment theory.

Core claim: Each country has a comparative advantage in goods that use its relatively abundant factor of production intensively.

Capital-abundant countries → export capital-intensive goods (machinery, IT)
Labor-abundant countries → export labor-intensive goods (textiles, agriculture)

Factor Price Equalization Theorem: Free trade tends to equalize wages and interest rates across countries over time.

Trade Policy: Tariffs and Non-Tariff Barriers

Tariffs

Taxes levied on imported goods that protect domestic industries but reduce consumer welfare.

Effect	Content
Producer surplus	Increases (domestic producers protected)
Consumer surplus	Decreases (higher prices)
Government revenue	Increases (tariff receipts)
Net social loss	Deadweight loss is created

Non-Tariff Barriers

Import Quotas: Direct limits on import volumes
Voluntary Export Restraints (VER): The exporting country voluntarily limits exports
Subsidies: Support for domestic export industries
Technical standards and sanitary regulations: Function as de facto trade barriers

Free Trade Agreements (FTAs)

Bilateral or multilateral agreements to eliminate tariffs and liberalize trade. Permitted as regional trade agreements under the WTO framework.

Examples: USMCA (US-Mexico-Canada), US-Korea FTA, EU Single Market.

Exchange Rate Determination

Exchange rate: The ratio at which two currencies are exchanged

Direct quote (US perspective): 1 EUR = $1.10
Indirect quote: $1 = 0.91 EUR

Exchange Rate Theories

Purchasing Power Parity (PPP): The same good should cost the same everywhere
→ Exchange rate = Domestic price level / Foreign price level

Interest Rate Parity: Exchange rates adjust so that expected returns are equalized across countries
→ Currencies of higher-interest countries face depreciation pressure

Effects of Exchange Rate Changes

Situation	Exports	Imports	Current Account
Dollar weakens (USD/EUR rises)	Price competitiveness improves → increases	Import costs rise → decreases	Improves
Dollar strengthens (USD/EUR falls)	Price competitiveness falls → decreases	Import costs fall → increases	Deteriorates

J-Curve Effect: When a currency depreciates, the current account may initially worsen before improving over time as trade volumes adjust.

Balance of Payments

A systematic record of all economic transactions between a country and the rest of the world.

Balance of Payments = Current Account + Capital & Financial Account

Current Account = Trade in goods + Trade in services
                + Primary income + Secondary income

Current account surplus: Exports > Imports → accumulation of foreign assets
Current account deficit: Imports > Exports → accumulation of foreign liabilities

The United States has run a persistent current account deficit, largely reflecting strong import demand and the dollar’s role as the world’s reserve currency. The Bureau of Economic Analysis (BEA) publishes quarterly balance of payments data.

Key Concept Cards

Comparative Advantage ★★★★★ : The principle that a country gains from trade by specializing in goods where its opportunity cost is relatively lower. Even a country with no absolute advantage can benefit from trade. Memory tip: Comparative advantage = specialize where opportunity cost is lower

Heckscher-Ohlin Theorem ★★★★☆ : Capital-abundant countries export capital-intensive goods; labor-abundant countries export labor-intensive goods. Memory tip: Abundant factor → export goods intensive in that factor

J-Curve Effect ★★★★☆ : After currency depreciation, the current account worsens in the short run before improving in the long run. The time lag in volume adjustment is the cause. Memory tip: J = dips first, then rises

Purchasing Power Parity (PPP) ★★★☆☆ : The long-run exchange rate is determined by the ratio of price levels in two countries. Memory tip: Exchange rate = Domestic price ÷ Foreign price

Practice Quiz

Q. Does trade occur when Country A has an absolute advantage in every good?

Yes. As long as comparative advantages differ, trade occurs and both countries benefit. Even if Country A is more efficient in everything, specializing where opportunity costs are lower and exchanging with Country B expands consumption possibilities for both.

Q. The USD/EUR rate moves from 1.05 to 1.15. What is the impact on US exports?

The dollar has weakened. US goods become cheaper in euro terms, improving price competitiveness and creating upward pressure on US exports. However, due to the J-curve effect, the current account may not improve immediately.

OIYO Editorial