Integration, Verification and Validation
Domain 7 tests integration, verification, and validation: assembling elements into a system, proving compliance, and proving fitness for use in the operational context.
Core rules and concepts
- Integration combines elements according to an integration plan. Strategies range from big-bang to incremental; incremental generally reduces risk by exposing interface defects earlier.
- Verification confirms that the system meets specified requirements: "did we build it right?" Validation confirms that it satisfies stakeholder needs in the operational context: "did we build the right system?"
- V&V planning starts with requirements. Each requirement needs a method-inspection, analysis, demonstration, or test-and acceptance criteria.
- Traceability links requirements to verification evidence and to validation scenarios.
Worked example
An aircraft landing-gear controller passes component tests. Integration reveals a timing conflict when the gear and brake systems share a bus. Verification catches the requirement violation. Validation later shows pilots can recover from the annunciation in a representative cockpit. Reasoning: component compliance cannot prove integrated behavior, and verification cannot prove operational fitness.
Traps that cost marks
- Conflating verification and validation.
- Leaving integration and V&V to the end of the program.
- Testing without acceptance criteria or traceability.
- Treating a successful demonstration as validation without operational context.
- Declaring integration complete when interfaces are merely connected, not exercised.
Key points
- Integrate incrementally to expose interfaces.
- Verification checks requirements.
- Validation checks needs in context.
- Plan methods and criteria per requirement.
- Trace evidence both ways.