Opportunity Cost
The value or benefit you give up by choosing one project instead of the next-best alternative.
Key Points
- Equal to the benefit of the best rejected option (e.g., NPV, ROI, or expected value).
- Applied when options are mutually exclusive and have comparable risk and timing.
- It is not a cash outflow; it is an economic comparison to guide selection.
- Do not include sunk costs; focus on future benefits you forgo.
Example
A portfolio team can fund either Project A with expected benefits of USD 1.2M or Project B with USD 900k. They select Project A. The opportunity cost of choosing A is USD 900k, the value of the best alternative they did not pursue.
PMP Example Question
A sponsor must choose between two mutually exclusive projects: Alpha with an NPV of USD 500,000 and Beta with an NPV of USD 420,000. If the sponsor selects Alpha, what is the opportunity cost?
- USD 80,000
- USD 420,000
- USD 500,000
- USD 920,000
Correct Answer: B — USD 420,000
Explanation: Opportunity cost is the value of the best alternative not chosen, which is the NPV of Beta (USD 420,000).
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