A Framework for Precise, Reusable Task Abstractions

Current methods for abstraction of task descriptions within the behavioral view are ad hoc, leading to imprecision, inconsistency, and ambiguity in task- and user-centered interface design representations. However, as interaction designers communicate with software designers and implementers, precise and consistent design representations are crucial.Our experience with the User Action Notation (UAN) reveals the most difficulty in lower levels of abstraction, those levels just above the articulatory level of task description. This level is crucial in interface design because it is the level at which user actions are used to manipulate interface artifacts, or widgets. Even cases believed to be simple and well understood, such as the select task, are seen to be problematic. We argue for inclusion of semantics in task abstraction. We also argue for guiding lower level abstraction within the task-subtask hierarchy by bringing to bear other kinds of abstraction hierarchies, particularly domain-oriented and taxonomical hierarchies.