Abstract

This thesis investigates the concept of personas, which are narrative representations of specific individuals of an interactive system's target audience. Personas aim at involving users in the design process to improve the usability of an interactive system before its development and deployment. This thesis first highlights the differences between design as defined in engineering and interaction design. Interaction design, which has its foundations in the human computer interaction community, is identified as an activity of researching, planning and modeling the software behaviours and services from the user's perspective. After discussion of user involvement in software development, we introduce a 3-steps model of the design process and review interaction design methodologies and their way to "know the users". Models of users' knowledge promoted in those methodologies are exposed and the persona model, rationale and lifecycle are described in details. Personas' uses and benefits are explained within the software engineering lifecycle and interaction design practices. Also, personas' mechanisms and effects are discussed in context of the design activity in terms of innovation, engagement and reflection-in-action. Then, with the help of two studies, a survey and an ethnographic report, personas are found useful and usable for software designers but their contribution in the overall software development lifecycle is questioned. Therefore, the need to formally assess the quality in use of personas and the challenges this tool faces in the software engineering community are identified.