Here’s this week’s 200 word idea thanks to TimHarford.com, Lifehacker.com and Professors David Dranove and Brett Saraniti at Kellogg.
In 1943, the American statistician Abraham Wald was asked to advise the US air force on how to reinforce their planes. Only a limited weight of armor plating was feasible, and the proposal on the table was to reinforce the wings, the center of the fuselage, and the tail. Why? Because bombers were returning from missions riddled with bullet holes in those areas.
Wald explained that this would be a mistake. What the air force had discovered was that when planes were hit in the wings, tail or central fuselage, they made it home. Where, asked Wald, were the planes that had been hit in other areas?They never returned. Wald suggested reinforcing the planes wherever the surviving planes had been unscathed instead.
As blogger Tim Harford points out, this makes for a classic example of selection bias and also a great life lesson. It is natural to look at successes. But, if we don’t examine our failures, we may end up putting our time, money, attention or even armor plating in entirely the wrong place.
Source and thanks to: Digitalroam.typedpad.com
‘The data that isn’t present may tell as important a story as the data that is.’
A Learning a Day 