The Sunk Cost Fallacy

Throwing Good Money After Bad

The sunk cost fallacy is the tendency to continue investing in something because of previously invested resources (time, money, effort), even when continuing is not the best decision going forward. Rational decision-making should only consider future costs and benefits — what you have already spent is gone regardless of what you decide next.

The Concorde fallacy. The British and French governments continued funding the Concorde supersonic jet long after it became clear the project would never be commercially viable. The billions already spent made it politically impossible to cancel, even though continuing guaranteed further losses. Economists call this 'the Concorde fallacy.'

Everyday examples:

• You finish a terrible movie because you paid $15 for the ticket.
• You stay in a failing relationship because you have 'invested' years.
• A company continues a doomed product because they have spent millions on development.

The rational question is always: 'Given where I am now, what is the best path forward?' — not 'How do I justify what I have already spent?'

Going Deeper

The concept covered in this lesson connects to broader analytical frameworks that students of politics, diplomacy, and global affairs encounter across many topics. Mastery requires moving beyond memorization to application — understanding not just what the concept means, but how it operates in real-world contexts.

Connecting Theory to Cases

The most effective way to deepen understanding is through case-based learning. For any analytical concept, identify three to five real-world cases that illustrate it:

• One canonical case: the most-cited example, often historical.
• One contemporary case: a current situation where the concept applies.
• One contrasting case: a situation that initially seems similar but where the concept does not apply, helping you understand the boundaries.
• One contested case: a situation where scholars disagree about whether the concept applies.

Working through cases this way builds the analytical flexibility that distinguishes strong policy and diplomatic thinkers from those who can only apply concepts mechanically.

Cross-Disciplinary Connections

Political concepts rarely operate in isolation. The most sophisticated analysis connects:

• Historical context: how did this concept develop, and why did it emerge when it did?
• Theoretical lineage: which scholars and traditions have shaped how the concept is understood?
• Empirical evidence: what does systematic research show about the concept's application?
• Policy implications: how do decision-makers actually use this concept in practice?
• Critiques: what are the strongest objections to the concept's usefulness?

The layered understanding that comes from working across these dimensions is what serious political and diplomatic research requires.

Building Your Analytical Vocabulary

For MUN delegates, debate competitors, IB and AP students, and political-research practitioners, building a substantial analytical vocabulary is one of the highest-leverage skills. Each concept you genuinely master is a tool you can apply across many different situations. Make a habit of working through Model Diplomat's broader glossary coverage of related concepts, building the connections that make your analytical work more sophisticated over time.