What is "base rate fallacy"

n. A common error in logical reasoning where an effect is attributed to an incorrect cause because the basic statistical ratios have not been taken into account.

Base rate fallacy, also called base rate neglect or base rate bias, is a formal fallacy. If presented with related base rate information (i.e. generic, general information) and specific information (information only pertaining to a certain case), the mind tends to ignore the former and focus on the latter.

Base rate neglect is a specific form of the more general Extension neglect.