DON PEPPERS points out a counter-intuitive RAF tactic that the two of us learned at the USAF Academy--you can efficiently plan for things when you patch up areas that aren't broken.
By analysing the parts of a returning aircraft that were not damaged after a bombing run, clever engineers concluded that those undamaged areas might have been responsible for other aircraft crashing. Flak damage happened all around the fuselages, engines, and cockpits of planes returning from hundreds of bombing runs. But if those areas could be perforated without the aircraft falling out of the sky, you might logically conclude the areas that weren't hit were actually more responsible for catastrophic aircraft loss.
The whole story is over on LinkedIn where Don Peppers shares astute observations.
Don Peppers -- "To Be More Successful, Study Failures", May 7, 2013.