1. A computer system for decision making in a decision situation, the computer system comprising: an input unit for receiving data corresponding to weights and/or probabilities, and/or values for a decision situation that can be represented in a generalized decision tree, a modelling unit for modelling the decision situation using at least one of a probabilistic decision model or a multi-criteria decision making model, where at least one of the probabilistic decision model or the multi-criteria decision making model is modelled in more than one level for generation of a decision frame. a unit for evaluating the decision frame using input data fed through the input unit, an output unit for outputting a result.