MBSE FAQ: How does MBSE enable Requirements Verification & Validation (V&V)?

Requirement Validation is typically the responsibility of system Stakeholders, who review Requirement specifications (e.g., SysML Requirement diagrams) to determine that they define "the right product" to be built. Requirement qualities checked during Validation include, but are not limited to, the following: Correctness, Completeness, Consistency, Clarity (Unambiguousness), Conciseness, Feasibility, Necessity, and Prioritization.

• SysML Support for Requirement Validation: SysML supports Requirement Validation by defining Requirements as first class visual modeling elements that can be classified (e.g., Functional, Performance, Interface, Design Constraints), organized into hierarchies (via Containment relationships), and assigned properties (TaggedValues) as needed (e.g., Risk, VerifyMethod, Priority, Level-of-Effort).

Requirement Verification is typically the responsibility of System Engineers and Systems Analysts, who (as per [Boehm 84]) "establish the truth of the correspondence between" the systems engineering product and its Requirement specification.

• SysML Support for Requirement Verification: SysML primarily supports Requirement Verification via two complementary relationships:
  • Satisfy («satisfy») dependency: The client model element fulfills a supplier Requirement. (See example.)
  • Verify («verify») dependency: The client TestCase («testCase») determines whether a supplier Requirement has been fulfilled. (See example.)

Another Requirement Verification best practice is to define a VerifyMethod property (TaggedValue) for Requirements with appropriate values (e.g., Analysis, Demonstration, Inspection, Test).