COMM1100 Business Decision Making
The Complete Study & Assessment Guide · T3 2026COMM1100 Overview
- UNSW Sydney
- Term 3, 2026
- 6 units of credit
- First-year Bachelor of Commerce
- Four in-tutorial tests
COMM1100 Business Decision Making is a first-year course in the UNSW Business School, taught in Term 3, 2026 on the UNSW trimester calendar. It is worth 6 units of credit, which the course frames as about 150 hours of study.
- Assessed by Weekly participation, four tests and a two-part case study
- Pass rule At least 15 of 30 marks across the tests
- Core move Compare marginal benefit with marginal cost
- Case study Stakeholders, market failure and the law in one analysis
What you get in the full COMM1100 Study & Assessment Guide
- 12 chapters, 54 pages — every assessed topic, week by week
- 30 original practice questions, each with a model answer
- 12 worked examples, solved the way COMM1100 marks
- 14 computed figures, redrawn from the course’s own numbers
- Before-you-submit checklist for the Assessment 3 (55%) — what markers reward, what costs marks
Free on this page: assessment table, chapter map, one worked example, key terms, FAQ. The rest is in the full study & assessment guide.
How COMM1100 is assessed
| Component | Weight | Format |
|---|---|---|
| Assessment 1: Participation and online quizzes | 15% | Part A (5%): pre-lecture and post-lecture Moodle quizzes. Part B (10%): tutorial participation marked on the rubric. Weeks 3-5 and 7-10; your mark is the average of the best 5 of 7 weeks. |
| Assessment 2: In-Tutorial Tests · hurdle | 30% | Four invigilated pen-and-paper tests, held in Weeks 3, 5, 8 and 10 in your enrolled tutorial, 7.5 marks each; designed for 15 minutes with 20 allowed; non-programmable calculator allowed. You must score at least 15 of the 30 marks to pass the course. |
| Assessment 3: Case-Study Analysis | 55% | Writing task on a case you choose. Part 1 (10%, about 400 words) due Week 8, Monday 2 November, 11:00am AEDT; Part 2 (45%, about 1,200 words) due Week 11, Thursday 26 November, 11:00am AEDT. Submitted as a Word document through Turnitin. |
What other students are asking about COMM1100
- Where can I find lecture notes or study guides for COMM1100 at UNSW?
- The COMM1100 study guide in AskSia Library covers Business Decision Making in 12 chapters, with the assessment table, a chapter-by-chapter topic map, key terms and a worked example, free to read on this page.
- Is there a final exam in COMM1100?
- No final exam is listed in the offering this AskSia Library guide is built from; COMM1100 is assessed by Assessment 1: Participation and online quizzes 15%, Assessment 2: In-Tutorial Tests 30%, Assessment 3: Case-Study Analysis 55%.
- What does COMM1100 cover on opportunity cost and the cost-benefit principle?
- In AskSia Library's COMM1100 guide, the Opportunity Cost and the Cost-Benefit Principle chapter explains marginal benefit and marginal cost, sunk costs, out-of-pocket versus opportunity cost, economic profit, costs measured in time.
- What does COMM1100 cover on comparative advantage and gains from trade?
- In AskSia Library's COMM1100 guide, the Comparative Advantage and Gains from Trade chapter explains absolute and comparative advantage, opportunity cost ratios, the feasible price range, specialisation and gains from trade.
- What does COMM1100 cover on demand, supply and market equilibrium?
- In AskSia Library's COMM1100 guide, the Demand, Supply and Market Equilibrium chapter explains reservation prices, horizontal summation, equilibrium algebra, shifts versus movements, simultaneous shifts.
What COMM1100 covers
COMM1100 starts with stakeholders and corporate responsibility, builds the market toolkit in Weeks 2 to 4 (opportunity cost, comparative advantage, supply and demand, elasticity, costs, market power, surplus and market failure), then turns to the legal rights of stakeholders: the legal system, contract, consumer and competition law, and employment law.
Stakeholders and Corporate Responsibility
Stakeholder definition, primary and secondary groups, shareholder and stakeholder views, normative and instrumental approaches, licence to operateThe opening week of COMM1100 sets up the lens used for the rest of the course. A business decision is examined three ways at once: through economics, through the law, and through corporate responsibility.
- Stakeholders as those who can affect or be affected by a decision
- Primary and secondary stakeholders; past, present and future groups
- The shareholder-centric view (Friedman, 1970)
- The stakeholder-centric view (Freeman, 1984)
- Normative and instrumental approaches to decision making
- Why corporate responsibility: licence to operate and corporate power
Opportunity Cost and the Cost-Benefit Principle
Marginal benefit and marginal cost, sunk costs, out-of-pocket versus opportunity cost, economic profit, costs measured in timeEconomics enters COMM1100 through one rule: take an action only if its marginal benefit is at least its marginal cost. The Week 1 practice question and the Week 2 and 3 problem sets apply it again and again, and the trap they set is always the same.
- Economics as choice under scarcity; models and empirical tools
- The cost-benefit principle: act if marginal benefit is at least marginal cost
- Opportunity cost as the worth of the best option given up
- Out-of-pocket costs versus opportunity costs; accounting versus economic profit
- Sunk costs and why they leave the comparison
- Marginal cost in hours and in forgone earnings
Comparative Advantage and Gains from Trade
Absolute and comparative advantage, opportunity cost ratios, the feasible price range, specialisation and gains from tradeWhy do people and countries trade instead of producing everything themselves? The Week 2 lecture answers with two definitions that students often blur.
- Absolute advantage versus comparative advantage
- Opportunity cost ratios for each producer and each good
- Specialisation according to comparative advantage
- The feasible price range between two opportunity costs
- Counting the gains from specialising and trading
- Production possibilities frontiers and their slopes
Demand, Supply and Market Equilibrium
Reservation prices, horizontal summation, equilibrium algebra, shifts versus movements, simultaneous shiftsThe competitive market model is the workhorse of the economics half of COMM1100. Buyers and sellers are price takers, each buyer compares a reservation price with the market price, and each seller does the same with marginal cost.
- Competitive markets and price takers
- Reservation prices and the buyer's and seller's cost-benefit rule
- Market demand and supply as horizontal sums
- Equilibrium, excess supply and excess demand
- Shift factors: substitutes, complements, income, input prices, joint products
- Movements along a curve versus shifts of the curve
Price Elasticity of Demand and Supply
Elastic, unit elastic and inelastic demand, determinants of elasticity, the point formula, the revenue testKnowing that quantity falls when price rises is not enough for a business decision; the firm needs to know by how much. Price elasticity answers that question.
- Elasticity as a ratio of percentage changes
- Elastic, unit elastic and inelastic classifications
- Determinants of demand elasticity
- Determinants of supply elasticity
- The point formula: price over quantity times one over the slope
- Elasticity along a straight demand line
Firm Costs and the Competitive Supply Decision
Fixed, variable, average and marginal cost, producing while price covers marginal cost, minimum average cost, entry and exitBehind every supply curve is a firm deciding how much to produce. The Week 2 practice set asks you to complete a cost table for a small cafe, and the Week 3 tutorial puts several identical cafes into a market and asks what happens to price and profit.
- Fixed, variable and total cost
- Average total cost and marginal cost from a cost table
- The price taker's horizontal demand curve
- Producing while price is at least marginal cost
- Minimum average cost as the lowest price worth opening at
- Market supply from identical firms
Market Power and Monopoly Pricing
Perfect versus imperfect competition, firm demand, marginal revenue below price, MR equals MC, lost surplusThe Week 3 lecture asks what happens when the conditions of perfect competition fail. If a seller has market power, its own demand curve slopes down, so selling one more unit means cutting the price on every unit.
- The three conditions of perfect competition
- Market power, differentiated goods and barriers to entry
- Firm demand for a price taker and for a monopolist
- Total and marginal revenue from a demand schedule
- Profit maximisation where MR equals MC, with price from demand
- The market-power continuum
Economic Surplus and the Case for Markets
Consumer, producer and total surplus, why competitive markets maximise surplus, price floors, equity caveatsHow should we judge whether a market does a good job? The Week 3 lecture proposes economic surplus: the gap between what buyers are willing to pay and what they pay, plus the gap between what sellers receive and their costs.
- What markets decide: who makes, who gets, how much
- Alternatives to markets: planners, queues and personal ties
- Consumer, producer and total surplus
- Why competitive equilibrium maximises total surplus
- Price floors and lost surplus
- The invisible hand and resource allocation across markets
Market Failure: Externalities and Private Information
Negative and positive externalities, social versus private cost, lost surplus, private information and unravellingMarkets maximise surplus only when their conditions hold, and the Week 3 lecture lists the main reasons they fail: imperfect competition, externalities and private information. This chapter covers the last two.
- Externalities: costs and benefits that fall on bystanders
- Classifying positive, negative and no externality
- Private versus social marginal cost and benefit
- Overproduction with a negative externality
- Underproduction with a positive externality
- Why a ban rarely maximises surplus
The Legal System and Contract Law
Common and statute law, civil and criminal law, essentials of a valid contract, conditions and warranties, breach and remediesFrom Week 4 the course turns to the legal rights of stakeholders.
- Law as a constraint and an enabler for business
- Common law and statute law; precedent and priority
- Criminal and civil law; burden and standard of proof
- Federal and state jurisdiction
- Essentials of a valid contract: offer, acceptance and the rest
- Conditions, warranties and exclusion clauses
Consumer and Competition Law
The Australian Consumer Law, misleading conduct, unconscionable conduct, unfair terms, consumer guarantees, cartels and market powerConsumer and competition law are the course’s main examples of law that supports markets by fixing their failures.
- The Australian Consumer Law and its regulators
- General protections and specific protections
- Misleading or deceptive conduct
- Unconscionable conduct and the factors courts weigh
- Unfair terms in standard form consumer contracts
- Consumer guarantees for goods and services
Employment Law and Workplace Rights
Employment as contract, employee or contractor, the safety net of minimum wage, NES and awards, unfair dismissalEmployees appear on every stakeholder map in COMM1100, and Week 9 turns to decisions involving employees and suppliers.
- Employment as a contract with implied duties
- Employees versus independent contractors
- Full-time, part-time, casual and fixed-term employment
- The safety net: minimum wage, National Employment Standards, modern awards
- Enterprise agreements and the better off overall test
- The Fair Work Commission and the Fair Work Ombudsman
Its question is simple to state and hard to answer well: when a business decides something, what do the economics say, what does the law allow or require, and what does responsible conduct demand?
The course learning outcomes ask you to explain how economic, legal and corporate responsibility principles interact, to identify and apply economic models, to identify the legal issues in commercial situations, to describe how business can contribute to the greater good, and to research and summarise valid information from suitable sources.
The first half builds the foundations of business decisions.
Week 1 introduces stakeholders and corporate responsibility, including the shareholder and stakeholder views of the firm and the normative and instrumental approaches to deciding. Weeks 2 and 3 teach decision making in markets: opportunity cost and the cost-benefit principle, comparative advantage and trade, supply, demand and equilibrium, price elasticity, imperfect competition, economic surplus and the reasons markets fail.
Week 4 turns to the legal rights of stakeholders, with optional readings on the legal system, consumers, contracts and employment. After a flexibility week, the second half applies these tools to decisions involving consumers, competitors, government and society, and employees and suppliers.
Assessment has three parts. Participation and online quizzes are worth 15%.
Four in-tutorial tests, held in Weeks 3, 5, 8 and 10, are worth 30% together, and you must score at least 15 of their 30 marks to pass the course. A two-part case-study analysis is worth 55%: a short Part 1 due in Week 8 and a longer Part 2 due in Week 11. This guide follows that structure, with worked examples that use fresh numbers and practice in the style of the tests.
Worked example · free
Should the campus cafe raise its price? An elasticity check
- +1Find quantity at the current price: Q = 300 − 40 × 4.50 = 120 coffees a day.
- +1Quantity falls by 40 for each $1 rise, so |E| = 40 × (4.50 / 120) = 1.5. Demand is elastic at $4.50.
- +1Test the rise: at $4.75, Q = 300 − 190 = 110, so revenue is 4.75 × 110 = $522.50 against 4.50 × 120 = $540 now.
- +1Interpret: because demand is elastic, the 5.6% price rise loses about 8.3% of sales, so revenue falls by $17.50 a day.
Key terms
- Stakeholder
- Anyone who can affect, or be affected by, an organisation's decisions, policies or practices, whether past, present or future.
- Opportunity cost
- What the best forgone option was worth when a choice is made, including income and time given up.
- Comparative advantage
- Having a smaller opportunity cost for a task than another agent; it decides who should specialise in what.
- Market equilibrium
- The price and quantity at which quantity demanded equals quantity supplied, so there is neither excess supply nor excess demand.
- Price elasticity of demand
- The percentage change in quantity demanded divided by the percentage change in price; above 1 in absolute value means elastic.
- Marginal revenue
- The extra revenue from selling one more unit; below price for a firm that must cut its price to sell more.
- Economic surplus
- Consumer surplus plus producer surplus: the total net benefit that trades create for buyers and sellers.
- Externality
- A cost or benefit that lands on people outside a transaction, whose interests the buyer and seller ignore.
- Private information
- Information one party to an exchange has and the other lacks, which can stop valuable trades from happening.
- Consumer guarantee
- A protection under the Australian Consumer Law, such as acceptable quality, that a business cannot exclude by contract.
- Unfair contract term
- A term in a standard form consumer contract that causes significant imbalance, is not reasonably necessary and causes detriment; it is void.
COMM1100 FAQ
What is the course about, and is it mainly economics?
It analyses business decisions through three lenses: economics, law and corporate responsibility. The economics is the largest single block in Weeks 2 to 4, covering markets, costs, market power and market failure, but stakeholder theory opens the course and the legal rights of stakeholders follow in Week 4.
How is the course assessed?
Participation and online quizzes are worth 15%, four in-tutorial tests are worth 30% together, and a two-part case-study analysis is worth 55%. The tests sit in Weeks 3, 5, 8 and 10; the case study is due in two parts, in Week 8 and Week 11.
Is there a pass requirement on the in-tutorial tests?
Yes. The assessment guide states that you must achieve a total of at least 50% on the tests, that is 15 of the 30 marks, to pass the course. Each test is worth 7.5 marks and must be sat in your officially enrolled tutorial with your student ID.
How much maths do the tests involve?
The tests may include numerical responses alongside multiple choice and short answers. Expect algebra with straight-line supply and demand, elasticity, cost tables, marginal revenue and areas of triangles for surplus; a non-programmable calculator is allowed but not required.
Can I use generative AI for the case study?
The course permits generative AI for Assessment 3 at the level of assistance with attribution. You must write the first version yourself, reference any AI output, and submit a separate document describing your use with a full transcript of the interactions.
What happens if I miss a tutorial test?
If you miss a test for reasons beyond your control, sign up within 24 hours for that week's Friday make-up Session A and bring your ID. If you also miss Session A, apply for special consideration; approved students sit later make-up sessions.
How can Sia help me prepare?
Sia, the AskSia AI tutor, can walk through a supply-and-demand or elasticity question step by step, check your working on a practice set, or quiz you on contract and consumer law terms. It explains methods and checks reasoning; it does not complete assessed work, and UNSW academic integrity rules apply.
Questions students ask in each COMM1100 chapter
- Are shareholders also counted as stakeholders?
- Yes. Shareholders can affect and are affected by the firm’s decisions, so they meet the definition. The debate between the shareholder and stakeholder views is about whose interests should come first, not whether shareholders count. Chapter 01 · Stakeholders and Corporate Responsibility
- Why should I ignore money I have already spent?
- Because a sunk cost is gone under every option. Including it changes the totals equally on both sides, or worse, it tempts you to continue something whose remaining benefits are lower than its remaining costs. Only future costs and benefits that differ between options matter. Chapter 02 · Opportunity Cost and the Cost-Benefit Principle
- Can one person have a comparative advantage in both goods?
- No. If a person’s opportunity cost of one good is lower, their opportunity cost of the other good, which is its reciprocal, must be higher. They can have an absolute advantage in both, but a comparative advantage in only one. Chapter 03 · Comparative Advantage and Gains from Trade
- What is the difference between a change in demand and a change in quantity demanded?
- A change in the good’s own price moves you along the demand curve and changes quantity demanded. Anything else that changes how much buyers want at every price, such as income or a rival’s price, shifts the whole curve and changes demand. Chapter 04 · Demand, Supply and Market Equilibrium
- Why does elasticity change along a straight demand line?
- The slope is constant, but elasticity also depends on the ratio of price to quantity. Near the top of the line price is high and quantity low, so demand is elastic; near the bottom the reverse holds, so demand is inelastic. Chapter 05 · Price Elasticity of Demand and Supply
- Why does a competitive firm face a horizontal demand curve?
- Because many rivals sell an identical product. If the firm charged more it would lose its customers, and in the long run it cannot profitably charge less because the market price already sits at the minimum of average cost. Chapter 06 · Firm Costs and the Competitive Supply Decision
- Why is marginal revenue below price for a monopolist?
- To sell one more unit the monopolist must lower its price, and the lower price applies to every unit it sells, not just the extra one. The revenue lost on earlier units is subtracted from the price of the new unit. Chapter 07 · Market Power and Monopoly Pricing
- Why does a competitive market maximise total surplus?
- Sellers with the lowest marginal cost do the selling, buyers with the highest marginal benefit do the buying, and trade continues until the last unit’s marginal benefit equals its marginal cost, so no further trade could add surplus. Chapter 08 · Economic Surplus and the Case for Markets
- Are the wages a new factory pays a positive externality?
- No. Wages and hiring are part of the transaction between the firm and its workers, so the benefits are internal. An externality would be an effect on outsiders, such as pollution, traffic or better local roads. Chapter 09 · Market Failure: Externalities and Private Information
- Is a price in an advertisement an offer?
- Generally no. Advertisements, catalogues and shop displays are invitations to treat. The customer makes the offer, and the seller accepts it, so a seller can usually refuse to sell at a wrongly advertised price under contract law. Chapter 10 · The Legal System and Contract Law
- Does misleading conduct have to be intentional?
- No. The prohibition does not require intention, fraud or negligence. The question is whether the conduct, judged by its overall impression on ordinary members of the affected group, was misleading or likely to mislead. Chapter 11 · Consumer and Competition Law
- Does calling someone a contractor make them one?
- No. Courts and tribunals look at the whole relationship, especially who controls the work, how payment is made and whether the worker runs their own business. A label that hides employment can be an unlawful sham arrangement. Chapter 12 · Employment Law and Workplace Rights
How to prepare for the assessments
Plan the term around the tests. Each test covers everything up to the previous week with the focus on the two weeks before it, so in the days beforehand rework those chapters' examples without looking and time yourself on two practice cards.
Keep a one-page sheet of the rules that recur, such as MB at least MC, the point elasticity formula, MR equal to MC and the area of a triangle, and add a line for each legal test, such as the essentials of a contract and the three limbs of an unfair term.
For the case study, choose a case early that has not been covered in teaching, map its stakeholders, name the market failure and the legal issues, and use Part 1 feedback before writing Part 2. Do the weekly quizzes on time; they are the easiest marks in the course.
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