Supporting Requirements Reuse in Notification Systems Design through Task Modeling

In hierarchical task analysis, designers study and decompose the tasks users perform while interacting with a system. Overlooking task analysis can have serious consequences on the design outcome. By making tasks clear to the designers, we can leverage an in-depth understanding of a usage scenario. Resulting from task analysis is a task model that explicitly enumerates the low-level tasks and activities a user can perform with a piece of software. Our first challenge was to identify a design space (notification systems) and knowledge storage approach (claims). By attaching claims to tasks in a hierarchical task analysis, the model creates a visualization of relationships, embodying the system requirements. Successfully adapting task modeling to model notification tasks shows promise in benefiting the requirements analysis of notification system design and promoting reuse. This paper describes a procedure and instantiation of hierarchical task analysis, to help designers identify the most important aspects to focus design and to support reuse of design knowledge within and between projects. The results of our usability study make us confident that users are able to understand the processes of task modeling if provided with sufficient help.