Exploring Requirement Change Propagation Through the Physical and Functional Domain

Prior research performed by Morkos [1], culminated in the automated requirement change propagation prediction (ARCPP) tool which utilized natural language data in requirements to predict change propagation throughout a requirements document as a result of an initiating requirement change. Whereas the prior research proved requirements can be used to predict change propagation, the purpose of this case study is to understand why. Specifically, what parts of a requirement affect its ability to predict change propagation? This is performed by addressing two key research questions: (1) Is the requirement review depth affected by the number of relators selected to relate requirements and (2) What elements of a requirement are responsible for instigating change propagation, the physical (nouns) or functional (verbs) domain? The results of this study assist in understanding whether the physical or functional domain have a greater effect on the instigation of change propagation. The results indicated that the review depth, an indicator of the performance of the ARCPP tool, is not affected by the number of relators, but rather by the ability of relators in relating the propagating relationships. Further, nouns are found to be more contributing to predicting change propagation in requirements. Therefore, the physical domain is more effective in predicting requirement change propagation than the functional domain.