Glossary Behavior & verification
What is a verification cross-reference matrix?
A verification cross-reference matrix (VCRM) lists each requirement against the methods that will verify it, so every requirement has a plan.
Also called VCRM, verification matrix, requirements verification matrix.
Verification cross-reference matrix (VCRM)
A verification cross-reference matrix, or VCRM, is a table with one row per requirement and a column for each verification method: inspection, analysis, demonstration and test. Each row marks the method or methods that will verify the requirement, and often adds the level at which it is verified, the activity that does it and its status. At reviews it shows that every requirement has a plan, and later a result.
Why it matters
It makes verification something you can check for completeness: a row with no method is a requirement nobody plans to prove, and a row with a failed result is an open problem. It also shows the verification effort, method by method.
How it goes wrong
- Marking methods without naming the activity that will carry them out
- Letting the matrix fall out of step as requirements change
- Calling a requirement closed when only some of its activities have passed
In Cairn
The Verification lens is a VCRM: one row per requirement, a column each for Inspection, Analysis, Demonstration and Test, and the requirement's state at the end of the row. Click an empty cell to add that method for that requirement. A requirement has passed when all its activities have passed, and is failing when any has failed or is blocked; the counts roll up on Overview. Each activity records its method, description, results and status. Cairn has no field for the level at which a requirement is verified.
Questions
- How is a VCRM different from a traceability matrix?
- A traceability matrix shows how requirements link to each other and to the design. A VCRM is about verification: which method will prove each requirement, and whether it has.
- When should a VCRM be started?
- As soon as requirements are written. Choosing a method for each one tests whether it can be verified at all, while it is still cheap to reword.
See it on your own system.
Describe what you are building and Cairn interviews you, then builds the first model with you.