The block “External factors” generates values for the uncontrollable variables describing the external factors that cannot be controlled/manipulated by the decision maker, but do affect the system performance, and therefore are required for forming a reliable decision. Indeed, ignoring the uncertainty on external factors could invalidate the results of the study. As for the generation of control options, a discrete approach is assumed, where a finite set of assignments to uncontrollable variables is considered. The generation mechanism is again not specified, since it is strictly dependent on the application. Gridding is a possible way in case of continuous variables. In many applications, uncontrollable variables are discrete by nature, e.g., a binary variable representing whether a third party undertakes a given action or not