Opportunity Cost
The real cost of choosing something is not only what you pay. It is the value of the best alternative you give up.
Compare your choice with the best realistic alternative you must forgo.
What am I giving up by saying yes?
Time, money, attention, staffing and strategic priorities.
Fast overview
Resources are limited. Choosing one use means not using them somewhere else. Opportunity cost is the value of the best forgone alternative.
It is broader than price. A free meeting can still consume two hours that had a better use. A profitable project can still be a weak choice if the same people and capital could create more value elsewhere.
Mental Model Compass
Learn it progressively
1. Name the scarce resource
Money, time, attention, people, capacity or space.
2. State the choice
Say what you are considering and what it consumes.
3. Find the best alternative
What would you most likely do if you rejected this option?
4. Compare value
Include time, learning, flexibility, risk and future options when relevant.
5. Choose on the margin
Does this option create more value than the best forgone alternative? If not, redirect the resource.
See it in practice
Executive time
A two-hour meeting may cost no money. Its opportunity cost is the best use of those two hours that is delayed or dropped.
Business capital
Investing ₱1 million carries both its cash cost and the value the best realistic alternative investment could have produced.
Learning
Five hours polishing notes costs the learning gain those hours could have produced through a higher-value study method.
Worked application
Add another initiative to a full leadership agenda
Scarce resource: senior leadership attention and execution capacity.
Proposed use: launch the new initiative now.
Best alternative: finish and improve the current priority.
Hidden tradeoff: starting now may split accountability and slow the current priority.
Decision test: Is starting now worth more than the value lost by weakening or delaying the best alternative?
Common mistakes
Comparing with nothing
Scarce resources almost always have another use.
Adding every rejected option
Focus on the best forgone alternative, not the sum of all possibilities.
Counting sunk costs
Past unrecoverable spending should not decide where future resources go.
Ignoring non-cash costs
Time, focus, flexibility and learning can matter even when no money changes hands.
When not to use it
Do not overanalyze tiny, reversible choices whose alternatives have nearly equal value. Use this model when resources are scarce, alternatives differ meaningfully or saying yes closes off something valuable.
Related mental models
Pareto Principle
Find where scarce resources may create disproportionate value.
Reversibility
Decide how much analysis a tradeoff deserves.
Second-Order Thinking
Compare how options affect future consequences and choices.