Verification and Validation: Techniques and Benefits

Verification asks: "Are we building the product right?" It checks whether software work products conform to specified requirements and design.

Validation asks: "Are we building the right product?" It checks whether the final/intermediate product satisfies actual user needs and intended use.

Verification techniques

1. Reviews: Requirements, architecture and design are examined by peers.
2. Walkthroughs: The author leads a team through the work product to identify defects.
3. Inspections: Formal, systematic examination using defined roles and checklists.
4. Static analysis: Tools analyze source code without executing it.
5. Traceability analysis: Requirements are traced to design, implementation and tests.
6. Document checking: Specifications and design artifacts are checked for consistency and completeness.

Validation techniques

1. Unit testing: Individual components are tested.
2. Integration testing: Interacting components are tested together.
3. System testing: The complete system is tested against requirements.
4. Acceptance testing: The customer/user evaluates whether the system meets acceptance criteria.
5. Regression testing: Existing behavior is checked after changes.
6. Usability and operational evaluation: The product is assessed in realistic use conditions.

Verification vs Validation

Verification	Validation
Focuses on conformance to specifications	Focuses on fitness for intended use
Often uses reviews and static techniques	Relies heavily on execution and user-oriented testing
Finds defects early in work products	Confirms behavior of the developed product

Benefits

• Detects defects early when they are cheaper to fix.
• Reduces rework and maintenance cost.
• Improves reliability and quality.
• Confirms requirements are implemented correctly.
• Reduces project risk.
• Improves customer confidence.
• Provides evidence that quality objectives are being met.

Conclusion: Effective V&V combines reviews, inspections, analysis and testing throughout development rather than waiting until the end.