Armoring the Bombers That Came Back

Most of us have heard the story of armoring British bombers, as it’s too good not to share, not to mention being straight from the David Brent school of management motivation. Here is the Wikipedia version:

Bomber Command’s Operational Research Section (BC-ORS), analysed a report of a survey carried out by RAF Bomber Command. For the survey, Bomber Command inspected all bombers returning from bombing raids over Germany over a particular period. All damage inflicted by German air defences was noted and the recommendation was given that armour be added in the most heavily damaged areas. Their suggestion to remove some of the crew so that an aircraft loss would result in fewer personnel loss was rejected by RAF command. [Patrick] Blackett’s team instead made the surprising and counter-intuitive recommendation that the armour be placed in the areas which were completely untouched by damage in the bombers which returned. They reasoned that the survey was biased, since it only included aircraft that returned to Britain. The untouched areas of returning aircraft were probably vital areas, which, if hit, would result in the loss of the aircraft.

Heard it before? I know I have — many times. It’s a touchstone in the bias literature, an evocative example of how focusing on the things that survive, rather than the things that fail, shapes and warps your conclusions.

The trouble is, is it true? Did this bomber plating survey really happen, and did the the RAF, under the force of Patrick Blackett’s team’s analysis, do the contrarian thing of armoring the untouched parts of the bombers that came back?

I’m not the first one to suggest that this story is very likely apocryphal. Read around at all and, while you’ll find the story repeated on blogs, in management sessions, and in probability texts, it’s never adequately sourced. There is no doubt that Blackett’s operations research group did hugely important work for the British during WWII, but the evidence is scant that it came to this conclusion, and made this accepted recommendation to the RAF.

If anyone has other information, I’d be delighted to hear it. [-]