The facilitator had already done a form of probabilistic sensitivity by
looking at the conditional probability distributions in Figures 6–16 to 6–20. Now, however, he systematically varied probabilities to see if the preferred decision would change with changes in the probabilities for a particular uncertainty. If there are more than two branches at a node, there are many ways to vary probabilities for a sensitivity analysis. One method is to put a probability pon the top branch and the rest of the probability (1-p) on the bottom branch, and then systematically vary p. If the top and bottom branches are the "best" and "worst" outcomes, you are varying in a systematic way between best and worst.