there’s a strong possibility of exponentially overestimating probabilities in the course of Fermi calculations.
Fermi calculations are done explicitly to account for the conjunction of individual events in the correct way. This again is not supported by the experiment which did not involve the subjects using Fermi calculations to prevent errors in probability theory.
One way is to apply an affective bias or motivated reasoning to each of several parameters, knowing in each case which direction would boost the favored conclusion. This makes more difference with more variables to mess with, each with multiplicative effect.
Well, yes, if you start by writing on the bottom line the probability you want, and then fudge the individual events’ probabilities to get that desired outcome, you totally ruin the point of Fermi calculations. But I wouldn’t accuse anyone presenting a Fermi calculation of having done that unless there was some particular reason to suspect it in that case.
One way is to apply an affective bias or motivated reasoning to each of several parameters, knowing in each case which direction would boost the favored conclusion. This makes more difference with more variables to mess with, each with multiplicative effect.
Well, yes, if you start by writing on the bottom line the probability you want, and then fudge the individual events’ probabilities to get that desired outcome, you totally ruin the point of Fermi calculations. But I wouldn’t accuse anyone presenting a Fermi calculation of having done that unless there was some particular reason to suspect it in that case.