Go Bayesian. With every passing month/year, multiply your expectation that the story is true by a fixed decay factor between 0 and 1; this simulates the exponen

Go Bayesian. With every passing month/year, multiply your expectation that the story is true by a fixed decay factor between 0 and 1; this simulates the exponential distribution. But also be sure to update how surprised you will be, if the story does ever corroborate!