Requirements verification and validation techniques

In Step 5, “Verify & Validate Requirements,” each requirement must be verified and validated to ensure that they are the correct requirement. This ensures that the requirements meet the overall objective of the system and all stakeholder needs. Verification and Validation should be done continuously throughout the development of requirements at every level and as part of baseline activities and reviewed during the System Requirements Reviews (SRR).

Definition: Verification and validation (V&V) are independent methods and procedures that are used to check if a component, product, service, or system meets its established requirements and specifications and that it satisfies its intended overall purpose.

Difference Between Validate and Verify Requirements

Requirements verification is the process of making sure that the system requirements are complete and accurate. Validating requirements is checking to see if the documented needs match the expectations of the project’s stakeholders.

• Validate: Confirms that a requirement meets the intent of the stakeholder. “Have the right requirements been specified.”
• Verify: Confirms that the requirements can meet the intended objective of what it is meant for. “Have the requirements been specified right.”

Visit: Verification and Validation for more information.

Validating Requirements

1. The set of requirements is correct, complete, and consistent,
2. A model can be created that satisfies the requirements, and
3. A real-world solution can be built and tested to prove that it satisfies the requirements.
4. Meets the Stakeholder intent

Requirements designers should go back to stakeholders again with the requirements document and review it. The requirements should also all be traced in a rational database at this point. Take Stakeholders’ comments and make changes; hopefully, they’re not any. You may need to revisit Step 2, “Write & Document Requirements,” if there are. Repeat the process until there is complete agreement among all stakeholders. When all requirements are agreed upon, a baseline can be established and managed in Step 6, “Manage Requirements.”

Purpose of Requirements Validation

The purpose of requirements validation is to ensure the right requirements are correct, complete, consistent and communicate stakeholder needs.

Verifying Requirements

The requirement must be verified to prove that each satisfies its stated requirement. Verification is a quality control process that determines if a system meets its system-level requirements. Inspection and demonstration is the main testing method used in Verification. It confirms that the requirements contain the necessary elements of well-written requirements that adhere to the rules of the organization’s development guidelines. Basically, “Is the requirement written correctly in accordance with the organization’s standards, guidelines, rules, and checklists?”. Verification can be done by:

• Prototyping: During prototyping, a simplified form of the software is made so that the requirements can be checked and any problems or limits can be found. It can help people see how the system works and understand it better.
• Inspection: A team of experts looks at the requirements in a planned way to find any mistakes, missing information, or inconsistencies. It can be done by hand or with tools that do it automatically.
• Modeling & Simulation: Simulating a system means making a model of it and trying how it works in different situations. It can help find problems with the standards that might not be clear from the documentation alone.
• Traceability Analysis: Traceability analysis involves keeping track of the relationships between the requirements and other artifacts, like design documents and test cases, to ensure the requirements are full, consistent, and verifiable.
• Expert Inspection: A team of experts looks at the requirements in a planned way to find any mistakes, missing information, or inconsistencies. It can be done by hand or with tools that do it automatically.
• Test and Evaluation (T&E): Testing means developing and running tests to ensure that the requirements meet the desired quality and usefulness standards. It can be done at different levels, such as unit testing, integration testing, and acceptance testing.

Purpose of Requirements Verification

The purpose of requirements verification is to guarantee that the requirements for a system are comprehensive, accurate, and consistent.

Requirements Development Steps

• Overview: Requirements Development Overview
• Step 1: Gather & Develop Requirements
• Step 2: Write & Document Requirements
• Step 3: Check Completeness
• Step 4: Analyze, Refine & Decompose Requirements
• Step 5: Verify & Validate Requirements
• Step 6: Manage Requirements

AcqNotes Tutorials

AcqLinks and References:

• Defense Acquisition Guidebook (DAG) – Chapter 4
• Requirements Development Checklist
• DAU Systems Engineering Fundamentals Guide
• Space and Missile Systems Center (SMC) Systems Engineering Primer & Handbook
• NASA Systems Engineering Handbook (large 9M file)
• EIA-632 “Processes for Engineering a System” – 7 Jan 99
• White Paper: Writing a Requirements Document “For Multimedia and Software Projects” by Rachel S. Smith
• White Paper: Requirements Development, Verification, and Validation Famous Failures by Bahill & Henderson