Logical Fallacy of the Week, Week 51: Prosecutor's Fallacy

Prosecutor's fallacy – a low probability of false matches does not mean a low probability of some false match being found.  The prosecutor's fallacy is a fallacy of statistical reasoning made in law. In this fallacy, the context in which the accused has been brought to court is falsely assumed to be irrelevant to judging how confident a jury can be in evidence against them with a statistical measure of doubt. If the defendant was selected from a large group merely because of the evidence under consideration, then this fact should be included in weighing how incriminating that evidence is. Not doing so is a base rate fallacy. This fallacy usually results in assuming that the prior probability that a piece of evidence would implicate a randomly chosen member of the population is equal to the probability that it would implicate the defendant.   To Read More…..