Applying usability cost-benefit analysis - explorations in commercial and open source software development contexts

This thesis explores whether usability cost-benefit analysis is helpful when applied to commercial and open source software (OSS) development contexts. First, the thesis examines the differences and commonalities among the existing usability cost-benefit analysis models. The results indicate that there are considerable variations in the usability cost-benefit analysis literature in how the different categories of usability costs and benefits are identified and documented. Second, the thesis examines how well the existing usability cost-benefit considerations fit into practice in closed source software development. The results indicate that there are considerable risks of failure when using usability cost-benefit considerations in the commercial development context, when the inherent costs of usability activities become apparent, concrete, and measurable. Conversely, the potential benefits of better usability remain vague, uncertain, and unconvincing to the management. In order to build better usability cost-benefit models and minimize the potential that the models have unforeseen inherent risks, as outlined in this thesis, researchers should focus strongly on bringing forward the possible benefits of usability instead of focusing on the costs of designing and implementing user interfaces that would be realized in any case, regardless of the usability activities. Third, the thesis identifies the parallels and differences between open source software development and closed source software development in order to identify how usability costs and benefits fit into OSS development. The usability costs and benefits specific to OSS development are reflected in the experiences of bringing usability into the OSS development context. The results indicate that it is possible to fit usability cost-benefit considerations into the OSS development context, even though there are no apparent financial or resource factors to be considered. Furthermore, to fit usability cost-benefit considerations into the OSS development context, the philosophy, principles, hierarchical structure, community structure, and characteristics of OSS development must be considered. Usability cost-benefit considerations that fit into the OSS development context might help convince core developers that usability activities are important and should be integrated into the project roadmap.