Verification and Validation - Short Note

Verification and Validation (V&V) are the two pillars of software quality assurance, applied throughout the SDLC.

Definitions

• Verification: "Are we building the product right?" - confirming that each work product (requirement, design, code) conforms to its specification. It is a static activity - done without executing the software.
• Validation: "Are we building the right product?" - confirming that the final product actually satisfies the customer's needs and intended use. It is a dynamic activity - done by running the software.

Difference Table

Aspect	Verification	Validation
Question	Building the product right	Building the right product
Checks against	Specification/design	User needs & requirements
Execution	No execution needed	Requires execution
Timing	During development	After development / at delivery
Examples	Reviews, walkthroughs, inspections, static analysis, reviews of SRS/design	Unit, integration, system and acceptance testing, alpha/beta testing
Found by	QA team, peers, reviewers	Test engineers, customer

Techniques

Verification (static): Reviews (informal, walkthrough, peer review, Fagan inspection), static analysis tools, formal/mathematical proof, traceability and document checks.

Validation (dynamic): Unit testing, integration testing, system testing, acceptance testing, prototyping, alpha and beta testing with real users.

Objectives

• Detect defects early, when they are cheapest to fix.
• Ensure correctness, completeness, consistency and traceability.
• Reduce rework, cost and project risk.
• Build customer confidence that quality goals are met.

Conclusion: V&V must run in parallel throughout the SDLC - validation without verification misses design flaws, and verification without validation never checks real user needs.