Qualification, Certification and Compliance Terminology
What the terms verification, validation, qualification, acceptance, certification, compliance, substantiation and approval mean — and why they are not interchangeable across industries.
What is it?
Engineering programmes use terms like verification, validation, qualification, acceptance, certification, compliance, substantiation and approval. These terms have specific meanings, but the meanings vary between industries. This page explains the terms and their sector-specific usage.
Term definitions
| Term | General meaning | Sector notes |
|---|---|---|
| Verification | Does the product meet the specification? | Universal — "did we build the thing right?" |
| Validation | Does the product meet the user need? | Universal — "did we build the right thing?" |
| Qualification | Testing/analysis to demonstrate the design meets requirements | Space and defence: formal test programme with qualification levels |
| Acceptance | Confirming each production item meets requirements | Space: acceptance test on each flight article |
| Certification | Formal approval by a regulatory authority | Aerospace: EASA/FAA type certification; not used in civil engineering |
| Compliance | Meeting the requirements of a standard or regulation | Broad usage; regulatory context |
| Substantiation | Demonstrating by analysis that a structure meets requirements | Aerospace-specific: structural substantiation report |
| Approval | Formal acceptance by the responsible authority | Programme-specific: can be regulatory or internal |
Why the distinction matters
In aerospace, "certification" means formal approval by EASA or FAA. In defence, the equivalent may be "qualification" or "acceptance" by the procuring authority. In civil engineering, "certification" may mean CE marking under a directive. The engineer must use the correct term for the applicable sector to avoid confusion and to communicate effectively with the responsible authority.
Where terminology differs by sector, state the sector context explicitly. "Qualification" in a space programme is not the same as "qualification" in an automotive context. Do not assume the terms are interchangeable.
Key relationships
- Verification + validation = the V&V process that underpins qualification and certification
- Qualification → certification: qualification evidence supports the certification case
- Substantiation → certification: structural substantiation is part of the type certification basis
- Compliance → certification: demonstrating compliance with each requirement builds the certification case