4.3.3 Portioning the Reachability Matrix
According to Warfield [56], ”the reachability set for a particular variable consists of the variable itself and the other variables, which help the variable itself and to form reachability set.” After that, the intersection of these sets is computed for each of the components individually. The elements with the same reachability and intersection sets occupy the top level of the ISM hierarchy. The top-level element in the hierarchy does not contribute to completing any other levels above it. After the top-level element has been determined, it is isolated from the other elements in the structure. The same method is utilized once more to determine the components of the subsequent level. This procedure is repeated until the level of each element is figured out. These levels give support to the construction of the diagram and ISM model. Table 5 presents the reachability set, antecedent set, intersection set, and levels for this study’s 11 criteria (RE practices categories for GSD organizations in the SSD process).