Welcome to Theme 4: Terms of Trade
Welcome to one of the most important and frequently tested topics in Theme 4 (Section 4.1: International Economics)! If you have ever wondered how trading nations get rich or why some developing countries have to export more and more crops just to buy a single tractor, you are in the right place.
Don't worry if international trade sounds complex at first. We will break down the Terms of Trade (ToT) step by step, using clear calculations, memorable everyday analogies, and targeted exam tips designed specifically for your Pearson Edexcel A Level Economics A (9EC0) exams.
1. What is the Terms of Trade?
The Terms of Trade (ToT) measures the relative price of a country's exports compared to its imports. In simple terms, it represents the international purchasing power of a country's exports.
The Core Definition: The Terms of Trade is the volume of imports that a country can buy for every unit of goods and services it exports.
An Everyday Analogy
Imagine you bake and sell artisan loaves of bread, and you use your earnings to buy coffee beans imported from a neighbour:
• If \(1\) loaf of bread buys you \(1\) bag of coffee beans, your trading terms are \(1:1\).
• If the price of your bread doubles while coffee bean prices stay the same, \(1\) loaf of bread now buys you \(2\) bags of coffee beans. Your "terms of trade" have improved (your bread has more purchasing power!).
• If coffee bean prices surge while your bread price stays flat, you might need to bake \(2\) loaves just to buy \(1\) bag of coffee. Your "terms of trade" have deteriorated.
Key Takeaway: The Terms of Trade is strictly a price ratio. It tells us how expensive our exports are relative to our imports on global markets.
2. Calculating the Terms of Trade
In Edexcel Paper 2 and Paper 3, you will often be asked to calculate the Terms of Trade index using index numbers.
The Official Formula
\(\text{Terms of Trade Index} = \left(\frac{\text{Index of Average Export Prices}}{\text{Index of Average Import Prices}}\right) \times 100\)
In shorthand: \(\text{ToT} = \left(\frac{P_x}{P_m}\right) \times 100\)
Memory Trick: Remember "X over M" — eXports stay on top!
Understanding Base Years & Movements
• In the base year, the export price index is \(100\) and the import price index is \(100\). Therefore, the base year ToT is always \(\left(\frac{100}{100}\right) \times 100 = 100\).
• An Improvement (Favourable Movement): The ToT index rises above \(100\) (or increases compared to the previous period). Export prices have risen faster than import prices (or import prices have fallen faster than export prices). The country can now buy more imports for a given volume of exports.
• A Deterioration / Worsening (Unfavourable Movement): The ToT index falls below \(100\) (or decreases compared to the previous period). Import prices have risen faster than export prices. The country must sell more exports to purchase the same volume of imports.
Step-by-Step Worked Example
Suppose Country A has the following data:
• Year 1 (Base Year): Export Price Index = \(100\), Import Price Index = \(100\)
\(\text{ToT}_{\text{Year 1}} = \left(\frac{100}{100}\right) \times 100 = 100\)
• Year 2: Export Price Index rises to \(120\), Import Price Index rises to \(105\)
\(\text{ToT}_{\text{Year 2}} = \left(\frac{120}{105}\right) \times 100 = 114.29\)
Interpretation: Country A's Terms of Trade has improved by \(14.29\%\). Each unit of exports now buys approximately \(14.29\%\) more imports than it did in Year 1.
Key Takeaway: Always multiply by \(100\) to express your answer as an index number, and remember that an index above \(100\) represents an improvement relative to the base year.
3. Factors Influencing a Country's Terms of Trade
Why do export and import prices change over time? We can divide the causes into short-run/medium-run and long-run factors.
A. Short-Run and Medium-Run Factors
1. Exchange Rate Fluctuations:
• Appreciation/Revaluation: Makes domestic currency stronger. Export prices in foreign currency rise, while domestic currency prices of imports fall \(\implies\) ToT improves.
• Depreciation/Devaluation: Makes domestic currency weaker. Export prices in foreign currency fall, while domestic currency prices of imports rise \(\implies\) ToT deteriorates.
2. Relative Inflation Rates:
• If a country has higher inflation than its main trading partners, its average export prices rise faster than the prices of imports coming from abroad \(\implies\) ToT improves in the short run (though domestic international price competitiveness falls).
3. Global Demand and Supply for Key Commodities:
• An increase in world demand or supply bottlenecks for a country's main export (e.g., oil for Saudi Arabia or gas for Qatar) raises \(P_x\) \(\implies\) ToT improves.
• A global price spike in essential imported commodities (e.g., energy or food for net importers) raises \(P_m\) \(\implies\) ToT deteriorates.
4. Tariffs and Protectionism:
• Imposing tariffs on imports raises the landed domestic price of foreign goods, altering the relative price structure of traded products.
B. Long-Run Factors
1. Relative Productivity and Technological Advances:
• Significant domestic productivity gains and technological progress in manufacturing lower unit production costs and export prices. While this makes goods more competitive in volume, it leads to a deterioration in the Terms of Trade index (\(P_x\) falls relative to \(P_m\)).
2. The Prebisch-Singer Hypothesis:
• The Theory: Over the long run, developing nations that rely heavily on exporting primary commodities (e.g., agricultural products, minerals) face a structural deterioration in their terms of trade relative to industrialised nations exporting manufactured goods.
• The Economic Reason: Manufactured goods have a high income elasticity of demand (\(YED > 1\)), whereas primary commodities have a low income elasticity of demand (\(YED < 1\), in line with Engel's Law).
• The Mechanism: As global real incomes rise over time, world demand for sophisticated manufactured goods expands rapidly, pushing up \(P_m\) for developing countries. Meanwhile, world demand for raw food and agricultural commodities grows at a much slower rate, causing \(P_x\) to fall relative to \(P_m\).
Key Takeaway: Short-run changes are largely driven by exchange rates, inflation differentials, and commodity price swings; long-run trends are driven by productivity changes and structural demand shifts explained by the Prebisch-Singer hypothesis.
4. Impact of Changes in the Terms of Trade
When the Terms of Trade changes, it has profound ripple effects across the macroeconomy. Examiners love to test your ability to evaluate these impacts on living standards, the balance of payments, and inflation.
1. Living Standards and Real National Income
• When ToT Improves: A country's purchasing power increases. Consumers can enjoy cheaper imported consumer goods and greater variety. Domestic firms purchase cheaper imported capital equipment and raw materials, enhancing consumer welfare and national real income.
• When ToT Deteriorates: The nation loses purchasing power. Imports become relatively more expensive, requiring the country to give up more domestic production to afford the same volume of foreign goods, reducing real living standards.
2. Current Account of the Balance of Payments
Warning: This is the most common area where students lose marks!
An improvement in the ToT (higher \(P_x\) relative to \(P_m\)) does not automatically improve the Current Account balance. The outcome depends critically on the Price Elasticity of Demand (PED) for exports and imports:
• If demand for exports is Price Inelastic (\(PED_x < 1\)): A rise in export prices leads to a proportionally smaller decrease in export volume. Total export revenue increases (\(P \times Q \uparrow\)), leading to an improvement in the trade balance.
• If demand for exports is Price Elastic (\(PED_x > 1\)): A rise in export prices leads to a proportionally larger collapse in export volume. Total export revenue falls (\(P \times Q \downarrow\)), causing a worsening (deterioration) of the current account deficit.
3. Cost-Push Inflation and Competitiveness
• Deteriorating ToT (via higher import prices): Drives up the cost of imported raw materials, fuels, and components. This shifts the short-run aggregate supply (SRAS) curve to the left, triggering cost-push inflation.
• Improving ToT (via rising domestic export prices): Signals that domestic goods are becoming more expensive on global markets, which can harm the international price competitiveness of domestic exporters over time.
Key Takeaway: Whether an improvement in the ToT is beneficial overall depends on the price elasticity of demand for exports and imports, and whether the change was caused by rising export prices or falling import prices.
5. Examiner Pitfalls & Common Mistakes to Avoid
Pitfall 1: Confusing "Improvement in ToT" with "Improvement in the Trade Balance"
Never assume that an improvement in the Terms of Trade means the trade deficit is shrinking. Remember that ToT measures price ratios, while the Balance of Payments measures total monetary values (\(\text{Price} \times \text{Quantity}\)). Always evaluate using \(PED\)!
Pitfall 2: Confusing Terms of Trade with the Exchange Rate or Trade Balance
The exchange rate is the price of one currency in terms of another. The trade balance is the difference between the total value of exports and imports. The Terms of Trade is the ratio of export price indices to import price indices.
Pitfall 3: Flipping the Formula
Always write \(\text{ToT} = \left(\frac{P_x}{P_m}\right) \times 100\). Putting import prices on top will invert your result and lose you calculation marks.
Pitfall 4: Treating Short-Run and Long-Run Causes as the Same
In essay questions, clearly separate temporary shocks (such as floating exchange rate changes or temporary commodity price spikes) from structural long-run shifts (such as the Prebisch-Singer hypothesis or long-term productivity divergence).
6. Chapter Summary & Quick Review
Quick Review Checklist:
• Definition: The ratio of average export prices to average import prices (\(\frac{P_x}{P_m} \times 100\)).
• Index Interpretation: Above \(100\) = Improvement (more imports per export); Below \(100\) = Deterioration (fewer imports per export).
• Short-Run Drivers: Exchange rate shifts (appreciation improves ToT), relative inflation rates, and global commodity price swings.
• Long-Run Drivers: Productivity improvements (can lower ToT) and the Prebisch-Singer Hypothesis (\(YED < 1\) for primary commodities vs \(YED > 1\) for manufactured goods).
• Current Account Link: Higher export prices improve the current account balance only if export demand is price inelastic (\(PED_x < 1\)).