The Legend of Abraham Wald

Colourized portrait of Wald and the famous graphical depiction of the ‘survivor bias’ concept Wald has become so famous for (Wikimedia Commons, 2021)

Historians of science sometimes lament the fact certain historical figures are famous for the wrong reasons. Alan Turing (1912-54) is perhaps the best example of this phenomenon. Most people associate Turing with the breaking of an encryption device called the German Navy Enigma, rather than his—arguably—much more important contributions to theoretical computer science. Another example is Albert Einstein (1879-1955), who is typically recognized for his mass-energy equivalence formula E = mc² rather than for general relativity. J. Robert Oppenheimer (1904-67) is another one, more frequently associated with being the director of the Manhattan Project than with the Born-Oppenheimer approximation, arguably a much more important scientific contribution.

In this essay I will argue that Abraham Wald (1902-50) is another such figure. His name, for…