Canoeing the Mountains: Christian Leadership in Uncharted Territory

by Tod Bolsinger

David McRaney, author of the book and the blog You Are Not So Smart, writes about “survivorship bias,” that is, the tendency to look only at the “survivors” or “stories of success” and draw conclusions about reality.14 McRaney discusses a group of World War II engineers who were trying to make bombers safer by studying the bullet hole patterns in the planes after returning from a mission. They knew that the planes needed more armor (and if they wanted it to fly they couldn’t put armor over the entire plane), so they tried to determine where to put the additional armor. When they examined the planes, they discovered that they were shot up most on the bottom of the plane, on the wings and near the tail gunner. So, the engineers made preparations for putting more armor there. But one statistician, Abraham Wald, challenged the underlying assumption by pointing out that the planes they were studying were the survivors—these are the planes that were not shot down. In other words, Wald said, this is exactly where we should not put more armor—a plane can survive even if shot up in the bottom, wings and near the tail gunner. So they needed to look at other areas of the plane to reinforce. Through several tests they discovered that adding more armor to the ailerons, engine, stabilizers and around the pilot made the planes safer. Only listening to a different interpretation allowed them to find the right solution.