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Survivorship Bias that Will Help You Make Better Decisions



Everyone loves a survivor. Sometimes we concentrate on surviving, fixate on that, and overlook everything else. This is a well known cognitive bias that psychologists refer to as “survivorship bias.”

Put simply, survivorship bias describes our tendency to focus on the people or things that have passed some kind of selection process and forget about other important factors.

The problem with falling prey to survivorship data is that it clouds your judgment and distracts you from getting to the root cause of a problem within your personal life, your team, or your product. It makes it easy to pattern-match and conflate correlation with causation.


Understanding survivorship bias and how it can cloud your judgment is the key to becoming a sharper, more critical thinking. That can lead to better team-decision making, building a more cohesive product, or making data-driven decisions like a scientist. Let’s walk through an example!


During World War II, the Allies mapped bullet holes in planes that were hit by Nazi fire.

They sought to strengthen the planes, reinforce areas heavily damaged by enemy artillery to be able to withstand these battles even more. The immediate decision was to rebuild and reinforce areas of the plane that had more red dots (or received more bullets). Theoretically, it was a logical deduction. After all, these were the most affected areas.


But Abraham Wald, a mathematician, came to a different conclusion: the red dots represented only the damage to the planes that were able to return, that came home.

The areas that really should reinforce, were the places where there were no points because these are the places where the plane would not survive being hit.


This phenomenon is called survival deviation. It happens when you look at the things that have survived when you should focus on the things you don't.

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