Improving Requirements Selection Quality in Market-Driven Software Development

Sammanfattning: The thesis aims at finding means for assessing and improving the requirements engineering (RE) process in order to enhance software product quality and increase the competitive edge of software organisations. Quality can be defined as the ability to satisfy the customers’ expectations. Thus, from an RE perspective, improved quality implies improved requirements elicitation and prioritisation efforts. The thesis focuses on software-developing organisations that release their product in several releases on an open market. These market-driven organisations do not have one single customer to negotiate a contract with, but rather a set of potential customers with various wishes that need to be prioritised. The thesis is based on empirical research strategies, including both quantitative and qualitative approaches. The research results include a survey of current RE challenges in market-driven organisations in which issues such as lack of communication, turbulent markets and problems with release planning emerged. Process behaviour was explored in an analytical model using queuing theory to model three process phases: screening, evaluation and implementation. The model was validated in a survey. Furthermore, a case study using model building and simulation visualises relations between product quality and lead-time. A post-release analysis method, called PARSEQ, was introduced in a case study, with the intent to evaluate the requirements selection quality in prior releases and find improvement suggestions. Finally, a controlled experiment comparing two requirements prioritisation techniques was conducted, with the result that the simple and intuitive technique was superior regarding time-consumption, ease of use and accuracy.