Functional and non-functional requirements prioritization: empirical evaluation of IPA, AHP-based, and HAM-based approaches

Throughout the requirements engineering phase, the process of giving precedence to one requirement over another is beneficial to accomplish projects on a predefined schedule. This process is referred to as requirements prioritization. Although plenty of research has been dedicated to proposing various approaches to perform the requirements prioritization, only a small number of prioritization approaches have been recently reported with the aim of considering both functional and non-functional requirements during the prioritization stage. However, it is not a straightforward task to decide which of these approaches could be selected for a given prioritization problem unless the main properties of these approaches are well-evaluated. Hence, a detailed evaluation of the recently proposed approaches in an empirical manner would be needed. In this paper, we performed two successive controlled experiments with the aim of evaluating the current requirements prioritization approaches. In the first experiment, we compared the integrated prioritization approach (IPA) with the other approach, called AHP-based approach, whereas in the second experiment, IPA was compared with the other state-of-the-art alternative, named HAM-based approach. In the experiments, evaluation was based on measuring three properties: actual time-consumption, accuracy of results, and ease of use. Statistical analysis of the results obtained from the two experiments showed a better performance of IPA on all the measured properties compared to both AHP-based approach and HAM-based approach. The findings would be useful for practitioners to choose the most appropriate approach for a given prioritization problem, and also could be used as a guideline by interested researchers for identifying trends before conducting a study in future.