Decision-making glossary
Hindsight bias
Hindsight bias is the tendency, once an outcome is known, to believe it was more predictable than it actually was. People who learn how something turned out overestimate what they would have predicted without that knowledge, and are largely unaware of the shift. Baruch Fischhoff demonstrated the effect experimentally in 1975.
In Fischhoff’s experiments, people read short accounts of unfamiliar events, one of them an 1814 British campaign against the Gurkhas of Nepal. Those told a particular outcome rated it as more likely than people told nothing, whichever outcome they were given, and they underestimated how much knowing it had changed their view. Fischhoff called this “creeping determinism.”
For teams, hindsight bias distorts learning. A decision that turned out badly looks obviously wrong in retrospect, so the people who made it are blamed for poor judgment when they may have made a reasonable bet that lost. A decision that turned out well looks wise even if it was lucky. Both lessons are wrong.
The practical defense is a record written before the outcome: what was known, what was expected, and how confident people were. Judge the decision against that record, not against what is known now, and do not let anyone edit the original reasoning after the result is in.
In Decize: Once a decision is marked made in Decize, its question, rationale, assumptions, forecast and reversibility cannot be silently rewritten to fit the result. See how →