Use Case - Limitations

Limitations

Limitations of Use cases include:

• Use cases are not well suited to capturing non-interaction based requirements of a system (such as algorithm or mathematical requirements) or non-functional requirements (such as platform, performance, timing, or safety-critical aspects). These are better specified declaratively elsewhere.
• Use case templates do not automatically ensure clarity. Clarity depends on the skill of the writer(s).
• Use cases are complex to write and to understand, for both end users and developers.
• As there are no fully standard definitions of use cases, each project must form its own interpretation.
• Some use case relationships, such as extends, are ambiguous in interpretation and can be difficult for stakeholders to understand.
• In Agile, simpler user stories are preferred to use cases.
• Use case developers often find it difficult to determine the level of user interface (UI) dependency to incorporate in a use case. While use case theory suggests that UI not be reflected in use cases, it can be awkward to abstract out this aspect of design, as it makes the use cases difficult to visualize. In software engineering, this difficulty is resolved by applying requirements traceability, for example with a traceability matrix.
• Use cases can be over-emphasized. Bertrand Meyer discusses issues such as driving system design too literally from use cases, and using use cases to the exclusion of other potentially valuable requirements analysis techniques.
• Use cases are a starting point for test design, but since each test needs its own success criteria, use cases may need to be modified to provide separate postconditions for each path.