“The lifecycle itself has essentially three tasks: requirements analysis, design/ testing/development, and installation, with the middle stage being the largest and involving many subtasks (see Figure 6.14). Note the production of a set of usability goals in the first task. Mayhew suggests that these goals be captured in a style guide that is then used throughout the project to help ensure that the usability goals are adhered to.
This lifecycle follows a similar thread to our interaction design model but includes considerably more detail. It includes stages of identifying requirements, designing, evaluating, and building prototypes. It also explicitly includes the style guide as a mechanism for capturing and disseminating the usability goals of the proJect. Recognizing that some projects will not require the level of structure presented in the fulllifecycle, Mayhew suggests that some substeps can be skipped if they are unnecessarily complex for the system being developed.”
From: Preece, J., Rogers, Y., Sharp, H. (2002), Interaction Design: Beyond Human-Computer Interaction, New York: Wiley, p.195