Outcome Bias

What is outcome bias?

Outcome bias is judging the quality of a decision too heavily by how it turned out, while overlooking the information and circumstances available when the choice was made.

What the original research found

Baron and Hershey (1988) tested outcome bias in five studies of medical decisions and monetary gambles. Participants had the information that was available to the decision maker, yet evaluated decisions more favorably when the outcomes were good.

An outcome-bias example

A coach might be praised for a risky strategy after a win and criticized for the same strategy after a loss. The outcome changed; the information and probabilities at the time of the decision did not. Baron and Hershey used controlled scenarios to separate the effect of knowing the result from the information available when the choice was made.

How to review a decision

Consider the evidence, alternatives, probabilities, and goals that were available at the time. Outcomes still provide useful feedback, especially across repeated decisions or when the original process is not fully known. The bias is giving the outcome too much weight—not using results to learn.

Choice-supportive bias concerns remembering or evaluating a chosen option more favorably after the choice.