Short answer: Testing measures characteristics of a sample. Inspection examines a product, process, installation or service and determines its conformity with specific requirements — or, on the basis of professional judgement, with general requirements. Certification is a third-party attestation that requirements are fulfilled, usually with ongoing surveillance. Each answers a different question.
Three questions, three services
| Testing | Inspection | Certification | |
|---|---|---|---|
| Question answered | What are the measured values? | Does this item, lot or installation conform now? | Can conformity be relied on over time? |
| Typical output | Test report | Inspection report or certificate for the object inspected | Certificate with a scope, maintained by surveillance |
| Uses judgement? | Mainly measurement | Often, by a competent inspector | Decision by the certification body after review |
| Body standard | ISO/IEC 17025 | ISO/IEC 17020 | ISO/IEC 17021-1 or ISO/IEC 17065 |
Type A, B and C inspection bodies
ISO/IEC 17020 recognises three types of inspection body according to their independence. A Type A body is a fully independent third party. A Type B body forms a separate, identifiable part of an organisation and inspects only for that organisation. A Type C body is also part of an organisation involved in the items it inspects but may inspect for others, with safeguards. Buyers who need independent inspection should ask which type they are dealing with.
Pre-shipment and lot inspection
For product lots, inspection usually combines visual and dimensional checks, labelling and packing verification, quantity counts and, where specified, sampling for laboratory testing. Sampling plans are often based on ISO 2859-1 acceptance-quality limits agreed in the contract. A clear inspection specification agreed in advance prevents most disputes.
What to ask for
- The requirements the item was inspected against, written in the report.
- The sampling plan and what was actually sampled.
- The inspector's name and the body's independence type.
- Photographic or measured evidence for each finding.
Key takeaways
- Inspection gives a judgement on a specific object at a point in time.
- Certification provides continuing assurance through surveillance.
- Neither replaces the other; many supply chains need both.
Next step
How an inspection differs from a certificate or a test report, the three types of inspection body under ISO/IEC 17020, and what a buyer should ask for.
Explore BVS inspection
