The evaluation procedure uses six qualitative evaluation labels as shown in Figure 2. These values range from satisfied, where the element is fully achievable, to denied, where the elements is completely not achievable. We also represent partial achievement and denial with partially or weakly satisfied and partially or weakly denied, respectively. The conflict label represents situations where there is a roughly equal amount of positive and negative evidence, and the unknown value represents the presence of evidence of an unknown polarity. These concepts are summarized in Table 1.
Figure 2: Label values from Lowest (minimum) to highest (Maximum)
Initial evaluation labels are the starting points in the evaluation. Often, these initial values are placed on leaf elements, elements without incoming links, as explained in Leaf Elements. Occasionally these values are placed on non-leaf elements in order to express a specific analysis question. Any of the initial labels displayed in Figure 1 can be used to set initial evaluation labels; however, typically fully satisfied or denied values are used, often to represent the selection or de-selection of particular design alternatives.
For example, Figure 3 depicts an illustration of giving initial labels that correspond to the analysis question in our example to two leaf elements, which are circled in red. We marked the Allow Peer-to-Peer Technology (Softgoal) as Denied and marked Produce PC Products (Task) as Satisfied.
Figure 3: Giving initial labels to leaf elements. Source: Horkoff (2006)
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