Concepts
Health psychology/Cognitive biases · Clinical reasoninglow yield
Sunk cost bias
What it means
Persisting with a diagnosis or management plan because of the time, effort or resources already invested in it.
Worked example
Continuing a failing treatment pathway because "we’ve come this far".
In the exam
Despite mounting evidence the working diagnosis is wrong, the team presses on with the original plan because so much has already been invested in it.
What settles it
Sunk cost is about not abandoning a committed plan. Anchoring is about not revising the initial estimate as new data arrive.
Classically confused with
Anchoring
Source: Croskerry