A Quantitative Approach for Assessing the Priorities of Software Quality Requirements

There are two challenges in software quality requirements specification and analysis: (a) software requirements are usually imprecise; (b) software quality requirements often conflict with each other. Software quality requirements are often prioritized to resolve their conflicts. However, the priorities of quality requirements are very difficult to assess and determine subjectively. In this paper, a quantitative approach is developed to assess the relative priority of requirements based on the trade-off analysis between conflicting requirements. One technique is based on the trade-off analysis between the satisfaction degrees of requirements and another is based on the marginal rate of substitution in decision science, which specifies the maximal amount of a decision attribute the customer is willing to sacrifice for a unit increase in another decision attribute. A technique is then introduced to transform relative priorities into numeric priorities of requirements so that they can be used in aggregation of requirements. The analytic approach developed in this paper enables an objective assessment of priorities of the requirements, which provides a solid formal foundation for resolving conflicts by prioritizing conflicting requirements