The term Use Case comes from software engineering, especially from research into the Object Oriented Unified Modeling Language (UML) and the Human Computer Interface.

Use cases lead to detailed requirements, a functional specification, testing metrics, and validation of the model.

Called a scenario by an Information Architect, the use case describes a task or goal to be accomplished by the user, or actor, or persona.

It also includes the specific sequence of actions needed to achieve the goal, plus alternative sequences, discovered by User Research, documenting exactly how the user reacts to the model - see Interaction Design.

The collection of use cases describes all the possible ways (good and bad, right and wrong) of using a system.

The results can be documented as Work Flow with a Flow Chart?, Bubble Chart?, or Data Flow Diagram?.