The Black Swan: The Impact of the Highly Improbable · chapter 4 · id the-black-swan-c4-03-abraham-wald-working-for-the-s

“Abraham Wald, working for the Statistical Research Group at Columbia University during WWII, demonstrated survivorship bias by showing that armor should be added to the parts of returning aircraft that showed the LEAST damage, because planes hit in those areas never made it back.”

needs contextconfidence: high⚠ extracted by pipeline, re-audit pending

Receipts

American Mathematical Society: The Legend of Abraham Waldsource alive

Wald's actual contribution was a series of technical memoranda on optimal placement of armor on aircraft. The popular story oversimplifies his work, which involved sequential analysis and optimal sampling theory, not a single flash of insight about bullet holes.

Wikipedia: Survivorship Biassource alive

Researchers from the Center for Naval Analyses examined damage to aircraft that had returned from missions. Abraham Wald argued that the military should reinforce the areas with the least damage on returning planes, because those were the areas where damage was most likely to be

Vintage Aviation News: Wald's Counterintuitive Armor Theorypaywalled — manual check queued

The military initially wanted to armor the areas showing the most damage. Wald's insight was that the holes in returning aircraft represented survivable damage. Missing areas indicated fatal hits -- on engines, fuel systems, and cockpits.

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