ECON6023 · International Trade
The Complete Exam Bible · S1 2027International Trade
ECON6023 International Trade is a University of Sydney postgraduate (Master's) unit of study in the School of Economics, worth 6 credit points and taught at graduate level (it presumes advanced undergraduate microeconomics). It runs in two arcs. The first arc is the theory of why countries trade and who wins and loses: comparative advantage and the Ricardian model, the Dornbusch-Fischer-Samuelson (DFS) continuum-of-goods extension, the short-run specific-factors model, the long-run Heckscher-Ohlin model, factor movements (migration and FDI), and the Krugman monopolistic-competition model of intra-industry trade. The second arc is trade policy: import tariffs and quotas, export subsidies and strategic trade, and trade agreements and the political economy of protection. It is a derivation-heavy unit — most theory marks come from re-solving a model from its assumptions (CES/Cobb-Douglas demand via the Lagrangian, Ricardian real wages, the DFS A(z) and B(z') curves, the Krugman markup and firm size), and applied marks from working a tariff-welfare diagram with labelled areas. Assessment, delivered through Canvas, is four pieces: two in-class quizzes (10% each, Weeks 5 and 10, 45 minutes, closed book), a 30% in-person mid-semester test (Week 8, 1 hour, closed book) and a 50% final exam (2 hours plus 10 minutes reading, closed book, three questions — two theory derivations and one applied trade-policy question). No explicit pass hurdle appears in the available course materials, so confirm the hurdle rules, the mark split and the permitted calculator on your Canvas Assessments page and the unit outline. The ECON6023 result feeds the Weighted Average Mark (WAM) that later postgraduate economics units build on.
What ECON6023 covers
ECON6023 runs across a 13-week semester, building from world trade patterns and comparative advantage through the neoclassical models (Ricardian, DFS, specific factors and Heckscher-Ohlin) to new trade theory and trade policy. Progress is checked by two in-class quizzes (Weeks 5 and 10) and a mid-semester test (Week 8), then consolidated in a 2-hour closed-book final exam worth 50%. Each chapter below maps to the unit's real teaching week and to the derivations you must be able to reproduce.
How ECON6023 is assessed
| Component | Weight | Format |
|---|---|---|
| In-class quiz 1 | 10% | Week 5 · 45 min · closed book · in class |
| In-class quiz 2 | 10% | Week 10 · 45 min · closed book · in class |
| Mid-semester test | 30% | Week 8 · in person · 1 hour · closed book |
| Final exam | 50% | Formal exam period · 2 hours (+10 min reading) · closed book · 3 questions |
Krugman (1980) monopolistic competition: markup, firm size, varieties and the gains from trade
- +1Demand and firm output. CES demand for variety i is cᵢ = (I/P)(pᵢ/P)^(−σ) with price index P = (Σ pⱼ^(1−σ))^(1/(1−σ)); aggregating over the L consumers, a firm sells yᵢ = L·cᵢ. Perceived demand has constant elasticity σ.
- +1Profit-maximising markup. Profit is π = pᵢyᵢ − w(α + βyᵢ). Setting marginal revenue equal to marginal cost with constant elasticity σ gives the constant markup p = wβ·σ/(σ−1). With w = 1, β = 1, σ = 2: p = 1·1·(2/1) = 2.
- +1Free entry pins firm size. Impose zero profit (free entry), p·y = w(α + βy), together with the markup to get y = α(σ−1)/β = 4·(2−1)/1 = 4. Output per firm is independent of market size L.
- +1Number of varieties. Full employment L = N(α + βy) gives N = L/(σα) = 1200/(2·4) = 150 varieties (labour per firm = α + βy = 4 + 4 = 8, and 1200/8 = 150).
- +1Gains from trade. Per-capita welfare is proportional to N^(1/(σ−1)), which here rises one-for-one with market size L. Opening to trade acts like doubling the effective market to L + L* — firm size and price stay fixed under pure CES, but the number of varieties available to each consumer doubles (to 300 in the L = L* case), and love of variety raises real income. The gain comes entirely through variety.
Key terms
- Comparative advantage
- A country has a comparative advantage in the good it can produce at the lower opportunity cost (lower autarky relative price). In the Ricardian model Home has a comparative advantage in good 1 iff a₁/a₂ < a₁*/a₂*. A country always has a comparative advantage in some good, even with an absolute disadvantage in both.
- Autarky relative price
- The no-trade relative price. Under perfect competition price equals unit labour cost (pᵢ = aᵢ·w), so the relative price of good 1 is a₁/a₂ = the slope of the (straight-line) Ricardian PPF. The free-trade world relative price must lie between the two countries' autarky relative prices.
- CES demand
- Constant-elasticity-of-substitution demand: cᵢ = (I/P)(pᵢ/P)^(−σ) with price index P = (Σ pⱼ^(1−σ))^(1/(1−σ)) and σ = elasticity of substitution. Relative demand is c₁/c₂ = (p₁/p₂)^(−σ); as the number of goods grows, the own-price elasticity tends to σ — the workhorse demand system for the Ricardian, DFS and Krugman derivations.
- Stolper-Samuelson theorem
- In the long run (Heckscher-Ohlin), a rise in the relative price of a good raises the real return of the factor used intensively in that good and lowers the real return of the other factor. Magnification: for a rise in Pc, ΔW/W < 0 < ΔPc/Pc < ΔR/R. Distinct from the short-run specific-factors result, where the effect on the mobile factor is ambiguous.
- Deadweight loss (trade policy)
- The net efficiency loss from a tariff/quota/subsidy, measured as triangle areas on the supply-demand diagram: the production loss b (home units made at a marginal cost above the world price) plus the consumption loss d. For a small country a tariff's net welfare change is −(b+d); a large country can offset it with a terms-of-trade gain e.
- Optimal tariff
- For a large country the welfare-maximising tariff is t* = 1/E*ₓ, where E*ₓ is the elasticity of foreign export supply. As the country becomes small (E*ₓ → ∞), t* → 0. Welfare rises with the tariff up to t* (terms-of-trade gain exceeds deadweight loss) and falls beyond it.
ECON6023 FAQ
Is ECON6023 hard?
It is demanding because it is derivation-heavy rather than descriptive. This is a graduate unit that assumes advanced microeconomics, and the theory marks come from re-solving a model from its assumptions — CES/Cobb-Douglas demand via the Lagrangian, Ricardian real wages, the DFS A(z)/B(z') curves and the Krugman markup and firm size — not from recalling results. Students who find it manageable are the ones who can reproduce each derivation on a blank page and who practise the tariff-welfare geometry with labelled areas, rather than reading passively. Because a correct final number without the working scores poorly, steady weekly practice (and not leaving it to STUVAC) is what protects your WAM.
Can AI help me with ECON6023?
Yes, as a step-by-step study aid. Sia is an AI tutor built to mirror how ECON6023 is actually taught and assessed at the University of Sydney: it can walk you through a CES demand derivation, the DFS marginal-good condition, a Krugman firm-size solve or a small- vs large-country tariff-welfare diagram one line at a time, and it checks your reasoning as you go. Bring your own tutorial or past-paper question and ask Sia to explain each step. It does not do graded assessment for you, and the University of Sydney academic-integrity policy still applies — use it to understand the method, not to produce work you submit.
Where can I find past exam papers / practice for ECON6023?
Start on Canvas, where the unit posts its practice material, tutorial questions with solutions, and the final revision session that works through past-exam questions. Search the University of Sydney Library's past-exam-paper collection for any released papers. The weekly tutorials (Ricardian, DFS, specific factors / Heckscher-Ohlin, Krugman, trade policy) are the closest match to the exam's three-question shape. This guide also includes a re-authored practice exam that mirrors the paper's structure — a theory derivation, a Krugman solve and a tariff-welfare calculation — with fresh numbers, and you can ask Sia to generate extra practice in the same style and explain each step. Confirm what is officially provided on Canvas.
What are the ECON6023 assessment rules and hurdles?
Assessment is two in-class quizzes (10% each, Weeks 5 and 10, 45 minutes, closed book), a 30% in-person mid-semester test (Week 8, 1 hour, closed book) and a 50% final exam (2 hours plus 10 minutes reading, closed book, three questions) — the weights sum to 100%. No explicit pass hurdle (for the final or overall) appears in the unit materials, so do not assume one: confirm any hurdle requirement, the exact mark split and the permitted (non-programmable) calculator on your Canvas Assessments page and the unit outline. Note that an older archived handbook listed a written report instead of the two quizzes; the current unit's assessment is the quizzes-plus-tests structure above.
What is on the ECON6023 final exam?
A 2-hour closed-book paper (plus 10 minutes reading time) worth 50%, with three questions: two theory derivations and one applied trade-policy question. The theory questions draw on CES/Cobb-Douglas demand across the Ricardian, DFS and Krugman (1980) models; the applied question is a tariff/quota/subsidy welfare calculation (small or large country). Marks vary by year (for example a 25/25/10 split). A non-programmable calculator is permitted. Eaton-Kortum (2002) and Global Value Chains are explicitly not examined. The exam sits in the University of Sydney Semester 1, 2027 formal examination period (around June 2027) — confirm the exact date, time and room on Canvas and the USyd exam timetable.
How to study for the exam
Treat ECON6023 as a set of derivations you must be able to reproduce cold, not a reading unit. Each week, redo that week's core model from its assumptions on a blank page: the Ricardian real-wage argument (w/p = MPL), the DFS A(z) = a*(z)/a(z) and B(z') = [z'/(1−z')]·(L*/L) curves and their intersection, the specific-factors magnification chain, the four Heckscher-Ohlin theorems (and how they differ from the short-run specific-factors result — a common exam trap), and the Krugman markup p = wβσ/(σ−1) and firm size y = α(σ−1)/β. For the policy half, drill the tariff-welfare diagram until the lettered areas (a, b, c, d, e) are automatic, and always check whether a tariff is prohibitive before computing revenue. Because the marking rule is 'show your work and label every diagram', rehearse writing full derivations under time pressure, and keep applied answers to about 200-250 words. Work the tutorial solutions and the Week 13 revision session's past-exam questions rather than only re-reading notes. When a step won't click, ask Sia to explain that single step a different way and set you a fresh practice question in the same style; it teaches the method and checks your reasoning, and it never substitutes for your own graded work. Confirm the exam date, room, weighting and calculator policy on Canvas and the University of Sydney exam timetable.
Your AI Economics tutor for ECON6023
Stuck on a hard ECON6023 question? Sia is AskSia’s AI Economics tutor — ask any ECON6023 International Trade question and get a clear, step-by-step explanation grounded in how the course is actually taught and assessed. Read this whole study guide free, then take your hardest questions to Sia.
