When Opportunity Cost Breaks Down

Frame opportunity cost as the textbook 'value of the next-best foregone alternative' and pose the limits question.

• Standard definition: opportunity cost = value of the next-best option not chosen.
• Assume it works for any decision: money, time, career, relationships.
• The driving question: where does this lens stop giving useful answers?

Force the learner to commit to a boundary before any evidence is shown.

• One decision: commit to whether opportunity cost applies cleanly or breaks down.

Show one case where the textbook rule works (choosing between two investment portfolios) and one where people visibly ignore it (leaving a stable job to retrain).

• Investment choice: comparable scale, reversible, clear foregone option → opportunity cost predicts behavior accurately.
• Career retraining: identity-laden, partially irreversible, foregone 'job' cannot be resumed at the same value → behavior diverges from the model.
• Pattern: the concept predicts behavior only in the first case.

Manipulate a single decision across three toggles (reversibility, scale comparability, feasibility of the foregone option) and watch whether opportunity cost produces a usable answer.

• Toggle reversibility on/off.
• Toggle whether the foregone option can be valued on the same scale.
• Toggle whether the foregone option is inside the feasible set.
• Observe when the 'value of the next-best foregone' becomes undefined or misleading.

State the three specific failure modes named by the simulator, with concrete examples for each.

• Incommensurability: comparing money vs. health, time vs. identity.
• Irreversibility + path dependence: quitting a career, ending a marriage, having a child.
• Empty feasible set: the 'next-best' alternative does not exist for the decision-maker.

Transfer the boundary test to a new situation the learner picks, walking through reversibility, comparability, and feasibility.

• Pick a real decision under consideration.
• Score it on the three boundaries.
• Predict whether opportunity cost will be a reliable guide there.

Directly answer: where does opportunity cost reach its limits?

• Opportunity cost is reliable only when choices are reversible, comparable on a single scale, and drawn from a known feasible set.
• Beyond that boundary — in identity, irreversibility, and incommensurable trade-offs — the tool does not give an answer; it gives a false precision.
• Practical takeaway: use opportunity cost to narrow options, then switch tools (values clarification, commitment devices, ethics) for the final choice.