Software Quality Evaluation for Evolving Systems in Distributed Development Environments
Abstract: Context: There is an overwhelming prevalence of companies developing software in global software development (GSD) contexts. The existing body of knowledge, however, falls short of providing comprehensive empirical evidence on the implication of GSD contexts on software quality for evolving software systems. Therefore there is limited evidence to support practitioners that need to make informed decisions about ongoing or future GSD projects. Objective: This thesis work seeks to explore changes in quality, as well as to gather confounding factors that influence quality, for software systems that evolve in GSD contexts. Method: The research work in this thesis includes empirical work that was performed through exploratory case studies. This involved analysis of quantitative data consisting of defects as an indicator for quality, and measures that capture software evolution, and qualitative data from company documentations, interviews, focus group meetings, and questionnaires. An extensive literature review was also performed to gather information that was used to support the empirical investigations. Results: Offshoring software development work, to a location that has employees with limited or no prior experience with the software product, as observed in software transfers, can have a negative impact on quality. Engaging in long periods of distributed development with an offshore site and eventually handing over all responsibilities to the offshore site can be an alternative to software transfers. This approach can alleviate a negative effect on quality. Finally, the studies highlight the importance of taking into account the GSD context when investigating quality for software that is developed in globally distributed environments. This helps with making valid inferences about the development settings in GSD projects in relation to quality. Conclusion: The empirical work presented in this thesis can be useful input for practitioners that are planning to develop software in globally distributed environments. For example, the insights on confounding factors or mitigation practices that are linked to quality in the empirical studies can be used as input to support decision-making processes when planning similar GSD projects. Consequently, lessons learned from the empirical investigations were used to formulate a method, GSD-QuID, for investigating quality using defects for evolving systems. The method is expected to help researchers avoid making incorrect inferences about the implications of GSD contexts on quality for evolving software systems, when using defects as a quality indicator. This in turn will benefit practitioners that need the information to make informed decisions for software that is developed in similar circumstances.
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