Inversion

Back in World War II, it was customary for technicians to repair the areas in which B52 bombers had been hit by gun fire and shrapnel. This practice seemed logical, until a man named Abraham Wald flipped the script on everyone. Instead, he reasoned that the Navy should actually reinforce the areas in which the planes were not shot. Wald figured that if the bombers were able to successfully make it back from combat, they obviously did not get hit in any vital areas. It was therefore wiser for the Navy to reinforce the other areas of the plane.

Charlie Munger calls this form of thinking Inversion. You do the opposite of what you would assume to be true, and evaluate the outcome. You will be very surprised with what you learn.