Use Case Modeling
A structured method for describing functional requirements from the user perspective. Captures actors, goals and interaction steps in concrete scenarios to support analysis, prioritization and testable derivation.
Classification
- ComplexityMedium
- Impact areaOrganizational
- Decision typeDesign
- Organizational maturityIntermediate
Technical context
Principles & goals
Use cases & scenarios
Compromises
- Outdated use cases lead to wrong assumptions in development.
- Excessive formality blocks rapid feedback.
- Unclear actor identification can obscure responsibilities.
- Focus on core scenarios and document alternatives concisely.
- Use simple, predictable role names for actors.
- Link use cases to acceptance criteria and tests early.
I/O & resources
- Product vision or business goals
- Stakeholder interviews and user stories
- Existing process or system documentation
- Documented use cases with primary and alternative scenarios
- Derivation of acceptance criteria and test cases
- Prioritized implementation packages and open questions
Description
Use Case Modeling is a structured method for identifying and modeling functional requirements from the user's perspective. It captures actors, goals and stepwise interactions in concrete scenarios and links business expectations to technical tests. The approach supports shared understanding, prioritization and derivation of implementation tasks.
✔Benefits
- Increases shared understanding between business and engineering.
- Enables clear derivation of acceptance criteria and tests.
- Helps prioritization by focusing on user goals.
✖Limitations
- Focuses on functional requirements, not on non-functional aspects.
- Can become unwieldy if documented at excessive detail.
- Requires active stakeholder involvement for valid results.
Trade-offs
Metrics
- Use-case coverage
Share of identified user needs covered by use cases.
- Testable acceptance criteria per use case
Number of clearly formulated, verifiable acceptance criteria per use case.
- Time to validation
Average time between drafting a use case and stakeholder validation.
Examples & implementations
E-commerce checkout
Use cases describe the sequence from cart to payment including exceptions like payment failures.
Support ticket workflow
Scenarios model ticket creation, prioritization and escalation paths.
Bank transfer
Use cases define permissions, confirmation mechanisms and error handling for transfers.
Implementation steps
Preparation: identify stakeholders and clarify goals.
Elicitation: run workshops, capture actors and primary scenarios.
Modeling: document primary and alternative paths.
Validation: review and adapt use cases with stakeholders.
Derivation: derive acceptance criteria, tests and implementation bundles.
⚠️ Technical debt & bottlenecks
Technical debt
- Incomplete or inconsistent use-case archives hinder maintenance.
- Outdated models without traceability to implementations.
- Lack of standardization leads to divergent modeling styles.
Known bottlenecks
Misuse examples
- Replacing user interviews with mere documentation of typical flows.
- Using use cases to prescribe technical implementation details.
- Assuming a single use case covers all user scenarios.
Typical traps
- Confusing actor with system component.
- Neglecting error and exception paths.
- Involving end users too late in validation steps.
Required skills
Architectural drivers
Constraints
- • Time constraints for workshops
- • Limited access to technical details for business stakeholders
- • Tool or notation constraints (e.g. UML version)