ECON8069 Chap.1 Decision Frames and Opportunity Cost
Decision Frames and Opportunity Cost
Business decisions are organised around four inputs: options, preferences, information and theory. The chapter shows why a decision must be judged using information available when it was made, then fixes a status quo so opportunity cost has one stable meaning across every active option.
It finishes by separating accounting profit from economic profit and by treating owner labour and property as resources with real alternative values.
Start with the decision point
Options must be feasible at the time of choice. Information is limited to what could be known then, while theory supplies a structured prediction for facts that remain uncertain.
Preferences provide the value measure used to rank possible outcomes. Keeping these roles separate makes a weak argument easier to diagnose: it may omit an option, rely on later information, hide an unsupported forecast or use a payoff that does not reflect the decision-maker's objective.
Use one stable reference
The course's opportunity-cost method fixes a status quo that remains available.
Its value is attached to every active option, so the reference does not change from row to row. Because the same value is subtracted each time, it does not determine which active plan ranks first.
It determines whether the best active plan is worth choosing instead of the reference.
Bring implicit resources into profit
Accounting statements record explicit cash costs, but a business can consume owner labour, owned premises and capital that could earn a return elsewhere. Economic profit subtracts those alternative values.
The resulting sign is a recommendation: positive economic profit supports leaving the status quo, negative economic profit supports staying, and zero means the active plan exactly matches the reference.
Write the conclusion twice
A complete answer states which active option has the largest payoff and whether that option clears the status-quo threshold. Those are different comparisons.
Printing both prevents a student from choosing the least-bad active plan when every available project is inferior to staying.
What this chapter covers
- 01
Options, preferences, information and theory
- 02
Contemporaneous information versus realised outcomes
- 03
A fixed status quo for opportunity cost
- 04
Accounting profit and implicit resources
- 05
Economic profit as the go-or-no-go measure
- 06
Mechanism, assumption and conclusion in short answers
Worked example · free
Choosing a studio against an outside option
- 2Fix employment as the status quo, so the opportunity cost for each active plan is $82,000.
- 2Studio economic profit is $30,000 and workshop economic profit is $14,000.
- 2Choose the studio and leave employment because it ranks first and clears the reference value.
Key terms
- Decision Option
- An action that is genuinely available to the decision-maker at the moment of choice.
- Information Set
- The evidence available when a decision is made, excluding facts learned later.
- Implicit Cost
- The value of an owner-provided resource that is used without a cash payment.
- Economic Profit
- Accounting profit after the opportunity cost of the fixed status quo is deducted.
Decision Frames and Opportunity Cost FAQ
Why not judge a decision by its outcome?
Outcomes include later shocks and luck. Economic evaluation asks whether the action was reasonable using the evidence and forecasts available at the decision point. New information should change the next choice, not rewrite the earlier information set.
Does opportunity cost rank active plans?
Not under the course's fixed-status-quo method. The same reference value is subtracted from every active plan, so their ranking is unchanged. Opportunity cost decides whether the best active plan clears the threshold for leaving the reference.
Can accounting profit be positive while economic profit is negative?
Yes. Cash accounts can omit the value of the owner's labour, property or capital. Once those alternative values are included, a cash-profitable activity can be worse than the available status quo.
How should uncertainty change a recommendation?
State the forecast used at the decision date, then vary its uncertain input to find the threshold at which the preferred option changes. This sensitivity check shows whether the recommendation is robust without using later outcomes as if they were known in advance.
Exam move
Build a two-column decision table. Put the status quo at the top, list each active payoff and subtract the same reference value from every row. For narrative questions, freeze the information date before discussing the outcome. End every calculation with two sentences: which active plan ranks first, and whether its economic profit justifies leaving the reference. After the outcome is known, conduct a separate forecast audit.
Record which assumption failed, whether that failure was foreseeable and what information should enter the next choice. Practise with one case where a careful decision loses because of a new shock and another where a reckless decision succeeds by luck. Explain why the outcome does not reverse the process judgement. For implicit-cost problems, list owner labour, premises and capital before reading the cash profit.
If the active plan is negative after those values, say explicitly that staying is the recommendation even when the accounts show a surplus. Keep sunk costs in a separate crossed-out row so they cannot influence the forward comparison. Then vary one uncertain payoff at a time and find the threshold at which the preferred choice changes; this makes the recommendation auditable instead of presenting a single fragile number.
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