If you want to be very precise, you need evidence which causes at least a 33 bit reduction in entropy between your prior and posterior estimates of the probabil

If you want to be very precise, you need evidence which causes at least a 33 bit reduction in entropy between your prior and posterior estimates of the probability of each person in the world being the one you're looking for. http://en.wikipedia.org/wiki/Entropy_(information_theory) http://en.wikipedia.org/wiki/Entropy_(information_theory) As the stuff posted on 33bits regularly demonstrates, it is surprisingly easy to get this much information for a whole lot of people.