This paper presents a development process with particular focus on non-functional properties. The process is built around the concept of measurements at different levels of abstraction. It distinguishes the roles of measurement designer and application designer. We propose the notion of multiple context models of measurements corresponding to different levels of abstraction. This enables us to provide CASE tool support for the refinement of non-functional specifications by requiring transformations between context models and measurement definitions to be specified by the measurement designer and using them to refine non-functional specifications. KEY WORDS Software Design and Development, Software Methodologies, Quality of Service, Component-Based Software