“There are some enterprises in which a careful disorderliness is the true method” – Herman Melville, Moby Dick
Asymmetry of Error
During the Ebola epidemic calls to ban flights from Africa from some quarters were met by accusations of racism from other quarters. Experts claimed that Americans were at greater risk of dying from cancer than Ebola, and if they must fret they should fret more about cancer than Ebola. One expert, with a straight Gaussian face, went as far as saying that even hospitals were more dangerous than Ebola. Pop science reached an unprecedented fizz.
Trader and mathematician, Nassim Taleb scoffed at these claims. Comparing the risk of dying from cancer to Ebola was flawed, he said, because the numerator and denominator of cancer don’t change dramatically moment to moment. But if you make an error estimating the risk of Ebola, the error will be exponential, not arithmetic, because once Ebola gets going, the changing numerator and denominator of risk makes a mockery of the original calculations.
The fear of Ebola, claimed Taleb, far from being irrational, was reasonable and it was its comparison to death from cancer and vending machines which was irrational and simplistic. Skepticism of Ebola’s impact in the U.S. was grounded in naïve empiricism – one which pretends that the risk of tail events is computable.