Boston.com / News / Boston Globe / Ideas / Operation everything: "In World War II, scientists from a wide range of fields attacked military problems with a potent combination of empiricism and mathematical models. When airplanes came back riddled with holes from enemy attacks, for instance, the intuitive response was to reinforce the armor where the holes were. But, noted the scientists, those were the planes that made it back. They didn't need more armor where they were hit. The real challenge was to figure out the places that had been hit in the planes that went down."