Managing Quality Requirements in Software Product Development

Abstract: Software product development companies experience different challenges in managing quality requirements compared to functional requirements. In this context, quality requirements are defined as requirements that describe a restriction on the system, and specify how well the system performs its functions. In a market–driven development context with large markets, potential customers, and strong competitors push the software product development companies to release the software product to a certain market segment at the right time with higher level of quality than the competitors. This thesis focuses on techniques and methods that support software product development companies that release their product to an open market. The goals are to find means to improve the ability to make early estimates of quality requirements with adequate accuracy, such as performance, in order to enhance high–level decision–making. This thesis is based on empirical research, including both quantitative and qualitative research design. The research results include a systematic literature review of empirical studies on quality requirements, which presents the state of research. The results show that there is a gap in the research literature of how cost estimation of quality requirements is conducted. How quality requirements are handled in practice is discovered and described in a survey in requirements engineering for embedded systems. From the survey, issues emerge such as when the quality level is good enough, and how to get quality requirements into projects when functional requirements are prioritized. A case study within the embedded software domain investigates how quality requirements metrics are used in an industrial context, which concludes that for a method to be successful, it is important that it is flexible enough to handle the diverse nature of quality requirements. Finally, a model for cost–benefit analysis of quality requirements, called QUPER, was set into operation in a case study. The intent was to evaluate and improve the model for supporting requirements prioritization and quality requirements roadmapping at early stages of release planning.