Evidence guide: Sunk cost and continuation decisions

The decision question

Should I continue because the next step is worthwhile, or because too much has already been invested?

Reviewed lenses

Sunk Cost Effect – when past costs influence the next choice — The sunk cost effect is a documented tendency for irrecoverable prior investments of money, time, or effort to influence later choices. A meta-analytic review found clear evidence for the effect overall, while also showing that its size and moderators differ between utilization decisions and progress decisions. The effect should not be used to label every choice to continue: future value, switching costs, uncertainty, and how close a project is to useful completion can all be relevant to a forward-looking decision.
Escalation of Commitment – when setbacks lead to more investment in the same course — Sunk-cost effects and escalation of commitment overlap but are not interchangeable. Sunk-cost research asks whether irrecoverable prior investments influence current choices. Escalation of commitment describes persistence or additional resource allocation to a failing course of action and can also be driven by personal responsibility, self-justification, project structure, and other factors.
Loss Aversion – when a loss can carry more weight than an equivalent gain — Loss aversion is a central component of prospect theory and many studies estimate losses as receiving greater subjective weight than gains around a reference point. However, the effect should not be summarized with one universal coefficient. A 2024 interdisciplinary meta-analysis of 607 estimates reported a mean coefficient near 1.96, while another 2024 meta-analysis of individual risky-choice datasets estimated about 1.31. A 2025 re-analysis of the larger dataset found little evidence of loss aversion in some symmetric, unordered designs, showing that task structure and analysis can materially change the result.
Prevention Bias – favoring preventive security controls over detection and response — Prevention Bias is a label introduced in experimental research on information-security investment. In that task, participants favored preventive controls over detection-and-response controls even when the experiment was designed so the two classes had the same return on investment. The evidence does not establish a broad psychological law that people generally overvalue prevention in healthcare, insurance, relationships, or every other domain.
Status Quo Bias – when the current option gets extra weight because it is already in place — Status quo bias describes extra preference for an option because it is the current or existing state. Classic experiments and field observations found disproportionate persistence with status quo options, but keeping the current option is not automatically a bias. Switching can have real financial, practical, learning or uncertainty costs that make staying reasonable.

Decision guides

How to use this page

Start with the decision, not with a label for a person. Open the evidence behind the lenses that fit, compare nearby concepts when needed, and keep uncertainty visible.