Glossary Behavior & verification
What are verification methods?
Verification methods are the ways to show a requirement is met: inspection, analysis, demonstration and test, chosen for the evidence each one needs.
Verification methods
Verification methods are the ways of showing that a product meets a requirement. The usual four are inspection (examining the item or its documentation), analysis (calculation, modeling or simulation), demonstration (operating the item to show that it works, with little or no measurement) and test (operating it under controlled conditions and measuring the result). Verification asks whether the product was built right; validation asks whether it is the right product.
Why it matters
Choosing a method forces the question of what evidence will prove a requirement, and a requirement no method can verify is usually badly written. Planning methods early also shows what tests, analyses and equipment the project will need.
How it goes wrong
- Writing requirements without asking how each will be verified
- Defaulting to test when analysis or inspection would give the evidence more cheaply
- Leaving verification planning until the design is finished
In Cairn
Cairn records each verification activity against a requirement, with its method (inspection, analysis, demonstration or test), a description, its results and a status: draft, planned, passed, failed or blocked. The Verification lens lays them out as a verification cross-reference matrix. Wording checks flag requirements that would be hard to verify as written, such as ones with words like "adequate" or a performance requirement with no number. The Verification specialist can propose activities, through Change Review.
Questions
- What is the difference between demonstration and test?
- Both operate the item. A demonstration shows that it works, with little or no measurement; a test measures how it performs under controlled conditions against a stated criterion.
- What is the difference between verification and validation?
- Verification shows the product meets its requirements. Validation shows it meets the user's actual needs in its intended use.
See it on your own system.
Describe what you are building and Cairn interviews you, then builds the first model with you.