Verification – Confirmation that Specifications are Met in Quality Assurance

Verification is a disciplined, methodical process used to establish that a product, system, process, or component strictly conforms to specified requirements, standards, and customer or regulatory expectations. It is a foundational practice in aviation, aerospace, medical devices, and other high-reliability, safety-critical sectors. Verification is not a one-time event, but a continuum of confirmation activities that begin at the earliest stages of design and persist through production, integration, and operational deployment.

Verification is defined by industry standards and regulatory frameworks such as ICAO Doc 9859 (Safety Management Manual), ISO 9001:2015, ISO 13485:2016, EASA Part 21, and FAA regulations. These sources require the acquisition of objective evidence—such as test results, inspection records, and reviews—that demonstrate compliance with all stated requirements.

Verification is vital for mitigating risk, preventing defects, and establishing traceability from requirements through to final product delivery. It applies to hardware, software, documentation, procedures, and processes. Every verification activity must be repeatable, transparent, and based on documented criteria and acceptance thresholds. In aviation, for example, airworthiness certifications require detailed verification of every design and production stage to ensure that aircraft and components are safe and conform to their type design. This includes document reviews, physical inspections, laboratory tests, static and dynamic analyses, and simulations.

Verification supports quality assurance by providing a factual foundation for decision-making, regulatory submission, and customer acceptance. The emphasis on objective evidence distinguishes verification from informal checks, ensuring that every claim of compliance is substantiated, auditable, and defensible.

Purpose of Verification in Quality Assurance

The purpose of verification in quality assurance is to ensure, at every stage of the product or process lifecycle, that outputs strictly conform to their respective input requirements and specifications. This approach is especially crucial in industries like aviation, aerospace, and medical devices, where failure can result in significant safety and operational risks.

Verification acts as a proactive barrier against nonconformity, ensuring that misinterpretations, design flaws, manufacturing defects, and process deviations are caught and resolved before final acceptance or operational use. Quality management systems (QMS) such as ISO 9001 and ISO 13485 embed verification activities into each process, from requirements capture and design to procurement, assembly, and delivery.

For example, the FAA’s AC 21-43 and EASA’s Part 21 regulations require manufacturers to verify that each aircraft or part conforms to its approved design data before issuing a statement of conformity. Verification is not limited to physical products—it applies equally to software (through code reviews and static analysis), documentation (by inspections), and operational procedures (via audits and walkthroughs).

The principal question verification answers is: Are we building the product right? By focusing on conformance to specification, verification systematically eliminates sources of error and ambiguity, reducing the risk of costly rework, regulatory rejection, or safety incidents.

In regulated environments, verification is often a legal and contractual requirement. Objective evidence produced during verification activities is retained as part of the quality record, supporting regulatory submissions, customer audits, and internal reviews.

Verification vs. Validation: Key Differences

Verification and validation are two fundamental aspects of quality assurance, often paired but distinctly different in their intention, methods, and timing.

• Verification confirms that the product, process, or system complies with its specified requirements, typically using activities such as inspections, document reviews, static analysis, and unit tests. It answers the question, “Are we building the product right?” and is performed throughout development, often as a static process.
• Validation ensures that the product fulfills its intended purpose and user needs under real or simulated operating conditions. It answers the question, “Are we building the right product?” and is a dynamic process, involving functional and system-level testing, field trials, or user acceptance testing.

This distinction is codified in standards such as ISO 9001:2015 and ICAO Doc 9760, which mandate both verification and validation as separate, complementary activities. Verification provides internal assurance of correctness, while validation assures external suitability and regulatory acceptance.

How Verification is Used

Verification is systematically embedded into every stage of the product or process lifecycle, especially in regulated industries. Critical junctures for verification include:

Verification Activities & Methods

Verification activities are adapted to the item being verified and the associated risk. Common methods include:

• Document Reviews: Comprehensive analysis of requirements, specifications, and test procedures to confirm completeness and compliance.
• Design Reviews: Structured, multidisciplinary evaluations to confirm that designs are feasible, compliant, and traceable to requirements.
• Code Reviews: Systematic inspection of software source code for adherence to standards, correctness, safety, and security.
• Inspections: Formal, checklist-driven assessment of physical products, documents, or processes, documented with findings and nonconformities.
• Walkthroughs: Informal group sessions for peer feedback and early error detection.
• Static Analysis: Automated or manual analysis of code, models, or documents without execution, identifying syntax errors, logic flaws, and nonconformance.
• Testing (Non-Destructive): Tests that do not damage the product, such as electrical continuity or leak tests.

All activities are documented, with results forming part of the quality record. Verification methods are typically defined in a Verification Plan, subject to regulatory and customer review.

Documentation and Objective Evidence

Verification is defined by the creation and retention of objective evidence—documented proof that requirements have been met. Examples include:

• Signed checklists
• Inspection reports with pass/fail criteria and measurements
• Records of nonconformities and corrective actions
• Traceability matrices mapping requirements to verification activities/results

In aviation and medical devices, objective evidence is essential for demonstrating compliance to regulatory authorities and is retained for the life of the product.

Examples of Verification in Different Industries

Software Development

• Code Reviews: Every line of code in safety-critical software is reviewed for compliance, logical soundness, and absence of vulnerabilities.
• Requirements Traceability: Each requirement is mapped to test cases, design elements, and code modules, ensuring complete coverage.
• Design Inspections: High-level and low-level design documents are examined to confirm correct allocation and definition of interfaces and algorithms.
• Static Analysis: Tools scan code for syntax errors, unreachable code, and security risks; required for regulatory software approval.

Manufacturing & MedTech

• Product Inspections: Dimensional checks, material verification, and functional tests are performed on all stages of production.
• Process Verification: In-process verification ensures process consistency, e.g., contact angle measurement in medical device coating.
• Equipment Calibration: Measurement equipment must be calibrated and traceable, with records maintained and out-of-tolerance equipment investigated.
• Supplier Verification: Incoming inspections and review of compliance certificates and test reports for third-party components.

Medical Device Manufacturing Example

Contact angle measurement is a non-destructive test to verify coating uniformity on medical devices. Measurements at multiple locations are logged; failures trigger investigation and corrective action.

Process Verification

Confirms that a process consistently produces outputs that meet all specified criteria, typically when every output can be measured/tested without destruction (e.g., dimensional checks, leak tests, torque verification).

Use Cases: When and Why to Use Verification

Decision Criteria

• If all critical output characteristics can be measured/tested, verification is sufficient.
• For complex or high-risk processes where not all characteristics can be measured post-production, validation is required.
• Regulatory bodies specify when verification, validation, or both are required.

Regulatory Considerations

• FAA/EASA: All parts and assemblies must be verified before release; objective evidence required.
• FDA QSR: Verification must be documented and records retained.
• ISO 9001/13485: Verification must be planned, executed, and recorded in the QMS.
• ICAO: Verification is a key element of safety management.

Failure to perform and document verification can result in findings, loss of certification, or product recalls.

Benefits of Verification

• Early Defect Detection: Prevents costly downstream corrections or recalls.
• Cost Efficiency: Less resource-intensive than correcting failures post-delivery.
• Regulatory Compliance: Forms the backbone of submissions, audits, and certifications.
• Risk Reduction: Reduces risk of nonconformance, process failures, and safety incidents.
• Continuous Improvement: Drives root cause analysis and process improvements.
• Customer Confidence: Increases trust and supports brand reputation.
• Traceability: Provides a clear audit trail for investigations or warranty claims.

Best Practices for Verification

Structured Approaches

• Define Clear Acceptance Criteria: Requirements must be measurable and unambiguous.
• Use Formal Methods: Follow documented procedures with defined roles and responsibilities.
• Plan Verification Activities: Integrate into the project lifecycle with scheduled activities and documented outcomes.
• Independent Review: Use personnel independent of developers to avoid bias.

Checklists & Traceability

• Checklists: Ensure all elements are reviewed, increasing consistency.
• Traceability Matrices: Map requirements to verification activities/results.
• Change Management: Update verification records as requirements change.

Integration with Validation

• Complementary Activities: Verification ensures conformance; validation ensures suitability for use.
• Feedback Loops: Use validation findings to refine verification criteria.
• Documentation: Maintain comprehensive records for both verification and validation.

Glossary of Related Terms