Critical values for guilt/innocence - Assessing beliefs versus making decisions

At this point a natural question raises spontaneously. What is the possible threshold of odds or of JL's to condemn or to absolve somebody? This is a problem of a different kind. It is not just a question of believing something, but on deciding which action to take.

Decision issues are a bit more complicate than probability ones. Not only they inherit all probabilistic questions, but they need careful considerations of all possible benefits and losses resulting from the action. I am not a judge and fortunately I have never been called to join a popular jury, on the validity of which I have, by the way, quite some doubts.28So I do not know exactly how they make their decisions, but personally, being 99% confident that somebody is guilty (that is a JL of 2), I would not behave the same way if the person is accused of a `simple' crime of passion, or of being a Mafia or a serial killer.

Giulio D'Agostini 2010-09-30