Unit 4 · Unit 4: The Global Economy
The Complete IB Economics Guide · IB EconomicsUnit 4 · Unit 4: The Global Economy
- The Complete IB Economics Guide
- IB Economics
- 4 sections
International Baccalaureate does not publish a per-unit weighting for this exam. Exam structure (official): SL: External Assessment (70%) · Paper 1 (75 min, 30%) · Paper 2 (105 min, 40%) · Internal Assessment (30%); HL: External Assessment (285 min, 80%) · Paper 1 (75 min, 20%) · Paper 2 (105 min, 30%) · Paper 3 (105 min, 30%) · Internal Assessment (20%). Be ready to carry the same unit skills and representations into a complete answer on every paper. Comparative advantage explains gains from specialization when opportunity costs differ. Trade can expand consumption possibilities, but the distribution of gains depends on factor mobility, adjustment costs, market power, and institutions.
- How IB Economics assesses this International Baccalaureate publishes no per-unit percentage for IB Economics; Paper 1 accounts for 30% of the SL total and 20% of the HL total. · SL: External Assessment (70%) · Paper 1 (75 min, 30%) · Paper 2 (105 min, 40%) · Internal Assessment (30%) | HL: External Assessment (285 min, 80%) · Paper 1 (75 min, 20%) · Paper 2 (105 min, 30%) · Paper 3 (105 min, 30%) · Internal Assessment (20%) · show the model with two production boundaries for an opportunity-cost comparison, a foreign-exchange demand-and-supply diagram with the quote defined, a table comparing several development indicators and their limits
- Key skills Benefits of International Trade and Economic Integration, Trade Protection: Tariffs, Quotas, Subsidies, and the Arguments For and Against, Exchange Rates, Balance of Payments, Sustainable Development and Measuring Development, Barriers to Economic Growth and Development, Economic Growth and Development Strategies, Absolute and Comparative Advantage (HL)
- How to study for Unit 4 This page turns two production boundaries for an opportunity-cost comparison, a foreign-exchange demand-and-supply diagram with the quote defined, a table comparing several development indicators and their limits into one route: Define the output unit, currency quote, or development indicator before calculating or stating a direction of change..
- The organizing decision Fix the units and comparison before judging trade, exchange-rate, or development evidence.
What IB Economics Unit 4 covers
Use this map to connect each assessed skill to the relationship or representation that makes it visible.
Benefits of International Trade and Economic Integration
comparative advantage; terms of trade; currency depreciation02Trade Protection: Tariffs, Quotas, Subsidies, and the Arguments For and Against
comparative advantage; terms of trade; currency depreciation03Exchange Rates
comparative advantage; terms of trade; currency depreciation04Balance of Payments
comparative advantage; terms of trade; currency depreciation05Sustainable Development and Measuring Development
comparative advantage; terms of trade; currency depreciation06Barriers to Economic Growth and Development
comparative advantage; terms of trade; currency depreciation07Economic Growth and Development Strategies
comparative advantage; terms of trade; currency depreciation08Absolute and Comparative Advantage (HL)
comparative advantage; terms of trade; currency depreciationInternational Baccalaureate does not publish a per-unit weighting for this exam.
Official unit name and weighting: IB subject guide / subject brief.
Unit map: connect trade, currencies, and development
Connect the published share to the unit model
Comparative advantage explains gains from specialization when opportunity costs differ. Trade can expand consumption possibilities, but the distribution of gains depends on factor mobility, adjustment costs, market power, and institutions.
Exchange rates are prices of one currency in terms of another. Demand and supply in the foreign-exchange market respond to trade, income, interest rates, expectations, and financial flows. Always define the quote before saying that a currency appreciated or depreciated.
Economic development is multidimensional. Income per person matters, but health, education, security, inclusion, institutions, and environmental sustainability also matter. Policy evaluation should compare indicators, affected groups, financing, implementation, and long-run resilience.
Global-economy questions require the units and comparison to be fixed before the conclusion. For trade, calculate opportunity costs in the same output unit and identify the lower cost. For an exchange-rate change, define the quote and mark the starting state, shift, new outcome, and direction. For development data, state the indicator setup and result, then explain both what the comparison suggests and what it cannot establish alone. Stakeholder consequences and conditions complete the judgment.
The decision that organizes this unit
Define the system and choose the route before calculating
Fix the units and comparison before judging trade, exchange-rate, or development evidence.
Define the output unit, currency quote, or development indicator before calculating or stating a direction of change.
Mechanism route and repair branches
Relationships to preserve
- Comparative advantage depends on lower opportunity cost, not on the largest absolute output.
- An exchange rate is the price of one currency in another, so the quote must be defined before direction words are used.
- Development judgments combine several indicators with stakeholder, financing, implementation, and sustainability limits.
Representations to read
- two production boundaries for an opportunity-cost comparison
- a foreign-exchange demand-and-supply diagram with the quote defined
- a table comparing several development indicators and their limits
Branches to reject
- using absolute output instead of opportunity cost for comparative advantage
- saying appreciation or depreciation without defining the currency quote
- treating one average as a complete measure of development
| Key concept | Why it's hard | What scores |
|---|---|---|
| Comparative advantage | Absolute productivity distracts from opportunity cost. | Calculate both costs in the same output unit. |
| Exchange rate | The quote direction is left implicit. | Define the currency units before converting. |
| Development | One average is treated as a full welfare measure. | Use several indicators and state limitations. |
| Trade comparison | Using absolute output alone. | Same-unit opportunity costs → lower cost → trade implication |
| Data judgment | Treating one indicator as a complete development ranking. | Calculated comparison → meaning → limitation |
| Currency analysis | Using appreciation without a base currency. | Define the quote before stating the direction of change. |
How IB Economics assesses Unit 4: The Global Economy
What a complete response must make visible
Match the task to evidence that a reader can audit, then check the most likely reasoning failure before finalizing the response.
| Task | Evidence to show | Hurdle |
|---|---|---|
| Benefits of International Trade and Economic Integration | comparative advantage; terms of trade; currency depreciation | using absolute output instead of opportunity cost for comparative advantage |
| Trade Protection: Tariffs, Quotas, Subsidies, and the Arguments For and Against | comparative advantage; terms of trade; currency depreciation | saying appreciation or depreciation without defining the currency quote |
| Exchange Rates | comparative advantage; terms of trade; currency depreciation | treating one average as a complete measure of development |
| Balance of Payments | comparative advantage; terms of trade; currency depreciation | using absolute output instead of opportunity cost for comparative advantage |
| Sustainable Development and Measuring Development | comparative advantage; terms of trade; currency depreciation | saying appreciation or depreciation without defining the currency quote |
| Barriers to Economic Growth and Development | comparative advantage; terms of trade; currency depreciation | treating one average as a complete measure of development |
| Economic Growth and Development Strategies | comparative advantage; terms of trade; currency depreciation | using absolute output instead of opportunity cost for comparative advantage |
| Absolute and Comparative Advantage (HL) | comparative advantage; terms of trade; currency depreciation | saying appreciation or depreciation without defining the currency quote |
Worked example: calculate comparative advantage
Read each question as it appears on the exam paper, choose your answer, then tap it to see the feedback.
Practice 1: Compare opportunity costs
Two countries have equal resources but different production possibilities.
With equal resources, Coastland can produce either 60 tonnes of cocoa or 30 machines; Highland can produce either 40 tonnes of cocoa or 40 machines. Calculate the opportunity cost of one machine in each country and identify comparative advantage.
Show your working.
Give each opportunity cost with units.
A. Coastland gives up 2 tonnes of cocoa per machine and Highland gives up 1, so Highland has comparative advantage in machines and Coastland in cocoa.
✅ Correct! 😊 This compares sacrifice per machine in the same units and selects the lower opportunity cost. Taking reciprocal costs then correctly assigns cocoa to Coastland.
B. Coastland has comparative advantage in both goods because it can produce more cocoa.
❌ Not quite 😭 This uses absolute cocoa output and assigns both advantages from one maximum. Comparative advantage depends on relative opportunity costs, not the largest production total.
Prep with Sia Agent
Free download for Mac and Windows. Choose your computer:
C. Coastland gives up 0.5 tonne of cocoa per machine and Highland gives up 1, so Coastland has comparative advantage in machines.
❌ Not quite 😭 The Coastland ratio is inverted: 30 ÷ 60 measures machines per tonne of cocoa. The requested cost is cocoa forgone per machine, which is 60 ÷ 30.
Prep with Sia Agent
Free download for Mac and Windows. Choose your computer:
D. Both countries have the same opportunity cost because each calculation uses all available resources.
❌ Not quite 😭 Equal resource quantities do not imply equal trade-offs. Their production boundaries have different slopes, giving different opportunity costs.
Prep with Sia Agent
Free download for Mac and Windows. Choose your computer:
Full explanation
- Step 1For Coastland, divide 60 tonnes of cocoa forgone by 30 machines gained: 2 tonnes per machine.
- Step 2For Highland, divide 40 tonnes of cocoa forgone by 40 machines gained: 1 tonne per machine.
- Step 3Highland has the lower machine cost, while reciprocal costs show Coastland gives up only 0.5 machine per tonne of cocoa.
- Step 4Assign comparative advantage in machines to Highland and in cocoa to Coastland.
Practice 2: Evaluate currency depreciation
Country R’s currency falls from 2.00 to 1.60 units of foreign currency per unit of R’s currency.
Using an exchange-rate diagram and a real-world example, evaluate whether this depreciation is likely to improve Country R’s economic performance.
Define the exchange-rate quote before analyzing the change.
Support the response with economic reasoning.
A. Define the quote, identify the fall as depreciation, show the relevant currency-market shift, trace export and import effects, and evaluate elasticities, time lags, inflation, stakeholders, and conditions.
✅ Correct! 😊 This fixes the direction of the quote before using appreciation language and builds a complete causal chain. The proposed limits support a conditional judgment rather than an automatic conclusion.
B. Call the change an appreciation because 1.60 is a smaller number, then argue that exports become dearer abroad.
❌ Not quite 😭 Under the stated quote, each unit of R’s currency buys less foreign currency, so it has depreciated. Reversing the direction also reverses the trade-price mechanism.
Prep with Sia Agent
Free download for Mac and Windows. Choose your computer:
C. State that depreciation always improves the trade balance and conclude without discussing responsiveness or production capacity.
❌ Not quite 😭 The conclusion is too certain. Trade volumes may respond slowly or weakly, and domestic producers may face capacity constraints or higher imported-input costs.
Prep with Sia Agent
Free download for Mac and Windows. Choose your computer:
D. Discuss several development indicators but omit the currency quote, exchange-rate market, and trade-price effects.
❌ Not quite 😭 Broader indicators can inform evaluation, but they do not replace the requested exchange-rate mechanism. The response would lack the model that connects depreciation to economic outcomes.
Prep with Sia Agent
Free download for Mac and Windows. Choose your computer:
Full explanation
- Step 1The quote falls from 2.00 to 1.60 units of foreign currency per unit of R’s currency, so R’s currency buys less and depreciates.
- Step 2Show the cause in the foreign-exchange market, with clearly labeled axes, the initial equilibrium, the shift, and the new lower exchange rate.
- Step 3Trace cheaper exports and dearer imports to net exports, output, employment, the price level, and affected consumers and firms.
- Step 4Evaluate price elasticities, time lags, imported inputs, spare capacity, retaliation, and inflation before giving a conditional judgment.
Key terms for Unit 4: Unit 4: The Global Economy
Models, uses, and boundaries
- Connect trade, currencies, and development
- The opportunity cost of a machine is cocoa forgone divided by machines gained. Key relationship for unit map: connect trade, currencies, and development.
- Opportunity cost identifies which country gives up less of the other good
- Comparative advantage belongs to the economy with the lower opportunity cost for the output. Opportunity cost identifies which country gives up less of the other good.
- The tariff wedge links the higher domestic price to imports and government revenue
- Tariff revenue equals the tariff per imported unit multiplied by the number of imports. The tariff wedge links the higher domestic price to imports and government revenue.
IB Economics Unit 4 FAQ
How much of IB Economics does Unit 4 carry?
International Baccalaureate does not publish a per-unit weighting for this exam.
What is the first move on a Unit 4: The Global Economy problem?
Define the output unit, currency quote, or development indicator before calculating or stating a direction of change.
Which relationships should I preserve?
Comparative advantage depends on lower opportunity cost, not on the largest absolute output. An exchange rate is the price of one currency in another, so the quote must be defined before direction words are used. Development judgments combine several indicators with stakeholder, financing, implementation, and sustainability limits.
Which representations should I practice?
Practice moving among two production boundaries for an opportunity-cost comparison, a foreign-exchange demand-and-supply diagram with the quote defined, a table comparing several development indicators and their limits.
What error should I check before submitting an answer?
Check for using absolute output instead of opportunity cost for comparative advantage; saying appreciation or depreciation without defining the currency quote; treating one average as a complete measure of development.
Evidence workshop
Continue from the free model into complete practice
The full unit guide continues with the chapter’s worked examples, figures, scoring tables, and answer checks.
- Worked example: calculate comparative advantage
- Worked example: calculate a tariff outcome
Full unit practice. Open the complete guide for the full evidence workshop and synthesis.
Related IB Economics unit guides
IB Economics Exam Guide & Review
The whole exam and its official unit sequence.01Unit 1: Introduction to Economics
International Baccalaureate does not publish a per-unit weighting for this exam.02Unit 2: Microeconomics
International Baccalaureate does not publish a per-unit weighting for this exam.03Unit 3: Macroeconomics
International Baccalaureate does not publish a per-unit weighting for this exam.How to study IB Economics Unit 4
Start with the organizing decision
Before solving, restate the decision in operational terms: Fix the units and comparison before judging trade, exchange-rate, or development evidence.. Your first written move should be to Define the output unit, currency quote, or development indicator before calculating or stating a direction of change..
Practice the same idea in several representations
Rotate through two production boundaries for an opportunity-cost comparison, a foreign-exchange demand-and-supply diagram with the quote defined, a table comparing several development indicators and their limits. Use each representation to practice Benefits of International Trade and Economic Integration, Trade Protection: Tariffs, Quotas, Subsidies, and the Arguments For and Against, Exchange Rates, Balance of Payments, Sustainable Development and Measuring Development, Barriers to Economic Growth and Development, Economic Growth and Development Strategies, Absolute and Comparative Advantage (HL), and explain what stays invariant when the surface form changes.
Turn each error into a repair check
After every attempt, audit the response for using absolute output instead of opportunity cost for comparative advantage; saying appreciation or depreciation without defining the currency quote; treating one average as a complete measure of development. Then redo only the first step that made the reasoning diverge, keeping units, direction, and model conditions visible.
Confirm current course details in the official IB subject guide / subject brief for the 2027 administration.