Friday, January 20, 2017

how to analyze a problem... the obvious conclusions inexperienced desk jockeys arrive at, or the thoughtful scientific logical method of cause and effect - using WW2 bombers

During WWII the Army wanted to minimize bomber losses to enemy fire.

The desk jockeys safe at home researched where bombers tend to get hit, intending to recommend  re-enforcing the parts of the airplane that get hit the most would result in more planes making it back

They found that when American planes came back from engagements over Europe, they were covered in bullet holes. But the damage wasn’t uniformly distributed across the aircraft. There were more bullet holes in the fuselage, none in the engines.

The red dots show where bombers were hit the most, so they told the army and  plane manufactures to put more armor on those sections.

 You don’t want your planes to get shot down by enemy fighters,
  so you armor them.
  But armor makes the plane heavier, and heavier planes are less maneuverable and use more fuel.         Armoring the planes too much is a problem;
  armoring the planes too little is a problem.
  Somewhere in between there’s an optimum.
  You have a team of geniuses (Statistical Research Group) in New York City is to figure out where that optimum is. Exactly how much more armor belonged on those parts of the plane? That was what they came to Wald for.

Frederick Mosteller, who would later found Harvard’s statistics department, was there.
Leonard Savage, the pioneer of decision theory
Norbert Wiener, the MIT mathematician and the creator of cybernetics, dropped by from time to time. Milton Friedman, the future Nobelist in economics, was often the fourth-smartest person in the room.
The smartest person in the room was usually Abraham Wald, and he had left Romania because the Nazis wanted to kill all Jewish people.

 It wasn’t the answer they got. The armor, said Wald, doesn’t go where the bullet holes are. It goes where the bullet holes aren’t: on the engines.

- how did you obtain that data?

- well, we looked at every bomber returning from a raid, marked the damages on the airframe on a sheet and collected the sheets from all allied air bases over months. What you see is the result of hundreds of those sheets.

- and your conclusion?

- well, the red dots are where the bombers were hit. So let’s enforce those parts because they are most exposed to enemy fire.

- no. the red dots are where a bomber can take a hit and return. The bombers that took a hit to the ailerons, the engines or the cockpit never made it home. That’s why they are absent in your data. The blank spots are exactly where you have to enforce the airframe, so those bombers can return.

He got strange looks, so he made it even simpler for the military to understand (if they were smart, they wouldn't be in the military, see (and I'm a vet, I know what I'm talking about, smart people go out and create wealth, the rest of the people either go in the military, or remain broke))

If you go to the recovery room at the hospital, you’ll see a lot more people with bullet holes in their legs than people with bullet holes in their chests. But that’s not because people don’t get shot in the chest; it’s because the people who get shot in the chest don’t recover.

BTW: You can see the result of this research today. This is the exact reason the A-10 has the pilot sitting in a titanium armor bathtub and has it’s engines placed high and shielded.

Abraham Wald was home schooled until college. No wonder he was brilliant, he never went to USA public schools run by the Dept Of Education.

Being a religious Jew, he did not attend school on Saturdays, as was required at the time by the Hungarian school system, and was thus home-schooled by his parents until college. His parents were quite knowledgeable and competent as teachers.

In 1928 he graduated in mathematics from the King Ferdinand I University.
In 1927, he entered graduate school at the University of Vienna, from which he graduated in 1931 with a Ph.D. in mathematics, Menger, the great mathematician mentored him.

Despite Wald's brilliance, he could not obtain a university position, because of Austrian discrimination against Jews.
 However, Oskar Morgenstern created a position for Wald in economics.
When the Nazis invaded Austria in 1938, the discrimination against Jews intensified. In particular, Wald and his family were persecuted as Jews.

Wald was able to immigrate to the United States, at the invitation of the Cowles Commission for Research in Economics, to work on econometrics research.

His family, all but a single brother, would later die in Auschwitz, the extermination camp.

The official name for the people inside the apartment was the Statistical Research Group, a cabal of geniuses assembled at the request of the White House and made up of people who would go on to compete for and win Nobel Prizes. The SRG was an extension of Columbia University, and they dealt mainly with statistical analysis. The Philadelphia Computing Section, another group made up entirely of women mathematicians, worked six days a week at the University of Pennsylvania on ballistics tables. Other groups with different specialties were tied to Harvard, Princeton, Brown and others, 11 in all, each a leaf at the end of a new branch of the government created to help defeat the Axis – the Department of War Math.


  1. Quite interesting that home schooling - caused by religious beliefs - ended up putting Wald in a better position. But then of course his parents were probably smarter than the teachers in school, which would make quite a difference.

    As for the conflict between armour (extra weight) vs. speed and agility, there's no easy answer. The P-47 could take a lot of damage caused by ground fire, but the lighter P-51 was a lot more economical to build and operate.

  2. Great story! Filed under "common sense isn't as common as is commonly thought."

  3. Again!One of the best sites on the web!THANKS :)

    1. You are welcome, and thank you! Tell me what I did right so I can repeat it!