A process framework for customising software quality models

The quality objective of many software organisations is to deliver software products that meet and or exceed customer expectations. The key to achieving this is to capture these expectations at the beginning of the project by clearly defining all quality requirements. The characteristics particularly defined in ISO/IEC 9126-1 (2001) provide the framework for specifying quality requirements. The ISO/IEC 9126-1 quality model is intended to be applicable to any type of software product or intermediate product. Before application this model needs to be tailored to a specific software and specific need. Since these characteristics cannot be directly measured this makes it difficult to directly prioritise and choose the most relevant characteristics and sub-characteristics. Hence a process framework that will link these characteristics and subcharacteristics to user needs is required. This will in turn help customise software quality models like ISO/IEC 9126-1 (2001) and other general software quality models. A process framework for customising software quality models is proposed in the text and it is further shown how this framework was applied in a real working environment in an attempt to quantitatively validate it. The results collected in the study showed that the framework could be used reliably in customising a generic software quality model at characteristic level only. The deviations at sub-characteristic level were due to unclear questions in the generated Generic Quality Questionnaire that resulted in misunderstandings. And the metrics used to create these questions were not fully tested for validity and reliability due to time constraints. Enhancements are discussed in the study and it is further shown how reliability can also be achieved at sub-characteristic level.