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Benefits of use cases
Use cases are generally regarded as an excellent technique for capturing the functional requirements of a system. In particular, use cases:
- Discourage premature design
- Are reusable within a project
- Are useful for scoping
- Have proved to be easily understandable by business users
- Can be written in a variety of styles to suit the particular needs of the project
- Are concerned with the interactions between the user and the system
- Put requirements in context, they are clearly described in relationship to business tasks.
- Help stakeholders to understand the nature and scope of the business area or the system under development
Look out for...
- Scenarios - a scenario is a chopped-down, plain-English version of a use case, i.e. a practical description without the technical description of a formal use case, that allows normal users to understand them and confirm if they describe a real situation
- Confusing use cases and use case diagrams - use cases (which are written specifications) are separate and distinct from use case diagrams (which are diagrams of the relationship between actors and groups of uses cases).
- Clarity - use cases do not automatically ensure clarity. Clarity depends on the skill of the writer(s).
- Learning curve - there is a learning curve involved in interpreting use cases correctly, for both end users and programmers. Since there are no fully standard definitions of use cases, each group must gradually evolve its own interpretation.
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Related information |
Bittner, K. & Spence, I. (2002) Use Case Modelling. Addison Wesley Professional, 2-3.
Cockburn, A. (2000) Writing effective use cases. Addison-Wesley. ISBN 0-201-70225-8 |
Alternative methods
The relationship between use cases and actors are diagrammed using use case diagrams. Use case diagrams are a UML-standardized (Unified Modelling Language) notation.
Proponents of agile methodologies (e.g. Xtreme Programming) often consider use cases too needlessly document-centric, preferring to use the simpler approach of a "user story". A user story replaces the formality and structure of a use case with an informal, iterative narrative. |
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