Survivorship Bias: The WWII Planes That Came Back

During World War II, US analysts studying bullet holes on returning bombers recommended adding armor exactly where the planes were hit most. The logic was airtight, the data was real, and the statistician Abraham Wald told them they had it precisely backwards. The flaw wasn't in the numbers. It was in which planes were sitting in the hangar to be counted, and which ones never made it back to be counted at all.

For founders and operators, this is survivorship bias in its cleanest possible form, and it quietly distorts decisions everywhere: studying winning companies for success patterns while the firms that did the same things and failed stay invisible, reading testimonials while churned customers go silent, hiring for traits your best people share without knowing if those traits also predict failure. The case sharpens the habit of asking who is not in your sample before you trust what the sample seems to say. Wald's reasoning, and the conclusion it forced, is what the app has you reconstruct rather than be handed.