Describing the UserWrap-up Discussion

When we think about tasks and activities, people have two distict modes of thought. One is procedural: what are the steps needed to complete a task? The other mode of thought is conceptual: what is the nature of the task, how does it relate to other tasks, and how does it relate to the concepts that task manipulates?

Object-oriented practice makes a similar distinction. Within use case diagrams and control classes tasks can be seen as concept—a classifier in UML terms. Within scenarios tasks can be seen as a series of procedural steps.

This discussion provided an object model that formally describes tasks and the entities that they manipulate as well as the presentation we design to support those tasks and the relationship among all of these pieces.

Applications of Formal Models of HCI Concepts

• A user interface design pattern describes a set of design elements and their configuration. The pattern then further describes the context in which use of the pattern is justified. The model of HCI concepts presented in this discussion provides a framework for describing user interface design patterns. The Patterns topic area makes use of this model—or more accurately, this metamodel—to document UI patterns.
• A development process consists of tasks that manipulate requirements, design elements, and design realizations. The model of HCI concepts presented in this discussion formally describes the artifacts used by usability professionals in the course of user-centered development activities. This formal model can be used to describe the HCI artifacts flowing through a development process. To the extent that these HCI artifacts largely overlap with the artifacts produced by other participants in the development process—database architects, for example—the formal model can be used to explicitly address this overlap and understand how to coordinate overlapping work.
• Understanding this explicit model of the user can also help you when using less formal techniques to capture the core information you need.

What's Next?

Consider exploring the Patterns topic next.