Outcome bias
Judging a decision by how it turned out rather than by how sound it was when made.
What it means
Outcome bias is the tendency to evaluate the quality of a decision based on its eventual result rather than on the information and reasoning available at the time the decision was made. Because outcomes are visible and salient while the prior uncertainty is not, observers project knowledge of the result back onto the moment of choice, much as in hindsight bias. The core insight it violates is that under uncertainty a good process can produce a bad outcome and a reckless one can get lucky — so outcomes are noisy signals of decision quality. The bias punishes sound judgment that happened to fail and rewards poor judgment that happened to pay off, which corrupts incentives and discourages well-calibrated risk-taking. It is closely tied to 'resulting,' the poker term for the same error, and it is hard to escape because the counterfactual outcomes are never observed. It matters in medicine, management, law, and finance, where blame and credit are routinely assigned on results alone.
Examples
A risky surgery that fails is called a blunder; the identical call that succeeds is called brave — though the decision was the same.
A manager who skipped the backups for two years is praised for efficiency right up until the morning the server dies. The decision was equally reckless on every quiet day before it.
Sending on a striker in the ninetieth minute makes the coach a genius if the header goes in and a fool if it hits the bar. He made one decision; the ball made the other.
First described in Baron & Hershey (1988).