EVOLVING USE CASES

You should always begin by developing an outline of a use case (in a step-by-step format) before delving into the details. In early iterations, during the elaboration phase, only a few use cases (those that are considered architecturally significant) are described in detail beyond the brief description.

Your model will often contain use cases that are so simple that they do not need a detailed description of the flow of events, and a step-by-step outline may be sufficient. The criterion for making this decision is that there should be no disagreement among the various stakeholders about what the use case means and that designers and testers are comfortable with the level of detail provided by the step-by-step format. Examples are use cases that describe simple entry or retrieval of data from the system. Toward the end of elaboration, all use cases that will be described in detail should be completed.