Consider how Walter Reed helped lower the death rate for wounded soldiers. It was 25 percent in the first Persian Gulf war; today it is less than 10 percent. Trauma care did not change. Medical personnel are actually stretched thinner than before. But they have tracked weekly data on injuries and survival rates, and actively looked for failures and how to overcome them.

Nothing was too trivial. During a visit with colleagues at Walter Reed early in the Iraq war, I was struck, for example, by their attention to eye-injury statistics. Instead of being proud of saving some soldiers from blindness, the doctors asked a harder, more unnerving question: why had so many injuries occurred? They discovered that the young soldiers weren’t wearing their protective goggles. Too ugly, the soldiers said. So the military switched to cooler-looking Wiley X ballistic eyewear. The soldiers wore their eyegear more consistently, and the eye-injury rate dropped immediately.