Abraham Wald, was a gentle kind-hearted man with a genius
that was breathtaking. He was born in
Hungary in 1902 and was the son of a Jewish baker. Fascinated with equations he studied hard and became a graduate
student at the University of Vienna.
His mentor was the great mathematician Karl Menger. Karl Menger had attended the Döblinger Gymnasium in
Vienna where two of his fellow students were Wolfgang
Pauli (Nobel Prize for Chemistry in 1938 ) and Richard Kuhn
(Nobel Prize for Physics in 1945). It
is perverse that in just one city during a short period of time so many great
minds began their careers.
Menger would pose problems to the young Wald, problems that
stumped great minds across academia.
Wald would spend time reflecting on his given task and invariably return
within a month with a solution to the problem and an urgent request for another
to solve. His hunger for problems and
ability to solve them became known to mathematicians in the US. When the Nazi threat grew this mathematical
prodigy was able to flee, albeit reluctantly, to the US from Vienna. It was a timely move. His entire family of nine members, bar one
single brother, died in the extermination camp Auschwitz.
Wald was put to work in the US on the Applied Mathematics
Panel. This group was posed questions
by the military and they would use their mathematical ability to answer the
query. For example, the navy was trying
to shoot torpedoes against Japanese vessels The panel was able to work out the speed of the ship from the distance
between the crests of waves. They then
had to factor in some adjustments to take into account the turning motion of
the ship but once they had the equations their predictions matched real life
experience and proved invaluable in targeting ships. At times what appeared real life observations could be the thing
that gives you a totally wrong answer.
The World War 2 bombing crews would limp back home peppered
by bullet holes. So high were the
losses, the military examined the planes that returned to see what particular
areas on the plane needed reinforced with steel plates. It would be impossible to reinforce the
entire plane as they could not fly with such weight. After careful investigation they noticed that the bullet holes
were found mostly along the wings, down the centre of the body and in the tail. The military wanted to put the armour on the
areas where holes appeared to be clustered.
Wald with his usual insightful genius stated that putting the armour
there would be of no benefit at all. He
had instantly recognised that the holes showed where a bomber could be shot and
still make it home. The armour should
be put on the areas where there were no bullet holes, the engine, stabilisers
etc. Any bullet hitting those would
never have made it home. He could see
the survivor bias that was derailing the statistical analysis the military was
so proud of.
... deep, beautiful and of fundamental importance.
“ a master at deriving complicated results in amazingly simple ways”.
He died in his late forties while on a lecture tour in India in a plane crash. Having saved so many who flew, with his mathematical genius, it is strangely disturbing that it was a plane that ended his life.