During World War II the Navy was losing a lot of aircraft. It was important to keep the planes from being shot down so there was much emphasis on the armor of the plane. But, armor makes the plane heavy and hard to maneuver. If they have too much armor…It’s a problem. Too little armor…it’s a problem. Somewhere in the middle was best. Finding the best solution was done through mathematics. Statistics and really smart people that knew how to make improvements based on data.
As you look at this picture you can see that the returning planes were hit the hardest on the wingtips, central body, and elevators.
The Navy planned to reinforce the heavily hit areas. The officers saw a chance to create a more efficient plane by reducing armor in the areas that were not being hit. The military reported 1.73 bullet holes per square foot in the fuselage. But, only 1.55 bullet holes per square foot in the engine. It made sense based on numbers to reinforce the hard-hit areas and reduce armor in the areas not hit.
Hmmm…let’s think about this. These planes were returning home. What about the planes that didn’t make it home?
Statistician Abraham Wald was an outside-of-the-box thinker. He presented that the missing bullet holes were on the missing planes. A significant number of planes were returning to base with a Swiss-cheesed fuselage. Wald suggested that instead, they reinforce the nose and the engines. I am quite certain many thought he was wrong in his thinking.
“The armor doesn’t go where the bullet holes ARE… It goes where the bullet holes AREN’T: ON the ENGINES!” said Abraham Wald.
It is said that countries don’t win wars by just being braver. The winners are generally the ones that get 5% fewer of their planes shot down, use 5% less fuel or get 5% more nutrition to their infantry at 95% of the cost. Math matters in war.
Wald’s idea was used in future wars such as Korea and Vietnam. There is no telling how many lives were saved. That’s the power of thinking outside of the box. We all have the ability to think differently. Most of the time we don’t share the best ideas because we are afraid of what others I’ll think.
The problem seen isn’t always the problem solved. Thanks Wald for being a pioneer for thinking differently!