Discussion: The purpose of labeling elements is to give initial values to those elements that correspond to the analysis question, acting as a starting point from where the evaluation and propagation starts. This labeling activity makes it easier for the readers of the model to understand at which points the evaluation started. In a further example, an expanded version of our previous example, suppose the analysis question is: “If the PC Product Provider’s notion of Compatibility, Security, Freedom of Use and Affordability are satisfied, are the main elements of the PC User and PC Product Provider satisfied?” The illustration depicts a correct set of initial labels for the leaf elements (red circles) that correspond to the analysis question and an incorrect set of labels (blue circles).