Non-functional Requirement Prioritization Approach

This paper proposes a non-functional requirement prioritization technique where both functional and non-functional requirements are prioritized and that is based on AHP (Analytic Hierarchy Process) technique employing suitable aspects. The non-functional requirements are further re-prioritized based on their dependency with high priority functional requirements and usage counts. The usage of the proposed method is illustrated with a hypothetical example. The technique is also executed on a case study of the evolving software and the technique resulted in selection of 16 requirements out of 30, yielding considerable reduction in the number of requirements to be implemented. Although the use of the AHP technique may limit the optimization, the use of the numerical assignment technique based on the usage count and dependency count do considerably reduce the number of requirements. The proposed technique prioritizes non-functional requirements independently from functional requirements but they are further selected in terms of their dependencies and usage counts with respect to functional requirements.