Sunk Cost Fallacy Fallacy
Also known as: Escalation of Commitment, Concorde Fallacy
What is Sunk Cost Fallacy?
The sunk cost fallacy occurs when someone continues a course of action because of resources (time, money, effort) already invested, rather than evaluating whether continuing is worthwhile based on future costs and benefits. Past expenditures that cannot be recovered are 'sunk costs' and should not factor into rational forward-looking decisions. However, the emotional attachment to past investment makes people reluctant to 'waste' what has already been spent.
Example
A software company has spent two years developing a product that market research now shows has no demand.
“We've already invested two years and $500,000 in this project. We can't just abandon it now — that would mean all that work was for nothing.”
The two years and $500,000 are already spent regardless of whether the project continues. The decision should be based on future prospects: will the product generate enough return to justify additional investment? If market research says no, continuing only adds more losses to the existing ones.
How to Spot It
- Past investment is cited as a primary reason to continue, rather than future expected value.
- Phrases like 'we've come too far to stop now' or 'we can't let that investment go to waste' are used.
- The emotional pain of 'wasting' past effort overrides rational analysis of future outcomes.
- The question 'should we continue?' is answered by looking backward instead of forward.
How to Counter It
- Reframe the decision: 'If we were starting from scratch today, would we begin this project?'
- Separate past costs (which are irrecoverable) from future costs and benefits.
- Point out that continuing a failing course of action increases total losses, not reduces them.
- Acknowledge the emotional difficulty while emphasizing that rational decisions must be forward-looking.
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