Requirements Traceability Matrix

A Requirements Traceability Matrix (RTM) is a document that maps each requirement to its origin (stakeholder need or regulation), the design elements that implement it, and the tests that verify it has been met. The RTM provides bidirectional traceability: forward traceability confirms that every requirement has a corresponding design element and test; backward traceability confirms that every design element and test exists to satisfy a requirement, with no gold-plating or unjustified complexity.

RTMs are mandated in safety-critical industries: IEC 61508 (functional safety), ISO 13485 (medical devices), and AS9100 (aerospace quality) all require demonstrable links between requirements and verification activities. Even outside regulated industries, RTMs are a best practice because they expose gaps early — a requirement with no linked test will likely be untested, and an untested requirement is a risk that will surface in production or customer use.

A well-maintained RTM includes: requirement ID, requirement text, source (standard, customer, internal), design reference (drawing number, specification), verification method (test, analysis, inspection, demonstration), verification status, and responsible engineer. In agile hardware teams, the RTM is often maintained in a lightweight tool rather than a formal document, but the traceability relationships are no less important.