Verification vs Validation
Built it right, or built the right thing? The distinction inspectors probe.
What a comparison is not
A comparison is SPEQ’s reading of how two published documents differ. Neither is the right answer, it is not a determination of which applies to you, and neither is summarised in a way that replaces reading it.
Verification confirms that an output meets its specified requirements — “did we build it right?” Validation confirms that it consistently does what it is actually for, under real conditions — “did we build the right thing, and does it reliably deliver?” The two words are used loosely in everyday speech, but in a regulated quality system they are distinct activities with distinct evidence.
| ASPECT | VERIFICATION | VALIDATION |
|---|---|---|
| Question answered | Does it meet the specification? | Does it consistently deliver the intended result in use? |
| Reference point | The written requirement / design spec | The intended use and user/patient needs |
| Typical activity | Inspection, test-against-spec, review, IQ/OQ checks | PQ / process performance qualification; demonstrating consistent output |
| When | Throughout build; each requirement checked | Once verified elements are integrated, under representative conditions |
| Evidence | Traceability to requirements; pass/fail against spec | Repeated, consistent performance across runs/conditions |
| Process context | Qualification (IQ/OQ) verifies equipment/installation meets spec | Process validation shows the process reliably yields conforming product |
| Device context | Design verification: outputs meet design inputs | Design validation: device meets user needs / intended use |
You are verifying when you check an output against a defined requirement — a dimension against a drawing, an installed utility against its design, a design output against its design input.
You are validating when you demonstrate, under representative conditions, that the whole thing consistently achieves its intended purpose — the process yields conforming product run after run; the device meets the user’s real need.
Verification is against the spec; validation is against the intent. In process terms, qualification (IQ/OQ) is verification of the equipment and installation, and process validation (PQ) is the demonstration that the process reliably makes good product. Inspectors probe the seam: teams that “validated” without first verifying — or that verified to spec but never showed consistent real-world performance — are the ones who get findings.
Verification vs Validation: frequently asked questions
Common questions on how Verification and Validation differ and when each applies.
What is the simplest way to remember the difference?
Verification = “did we build it right?” (meets the specification). Validation = “did we build the right thing?” (consistently delivers the intended use). Verification checks against the spec; validation checks against the purpose.
Is qualification (IQ/OQ/PQ) verification or validation?
IQ and OQ are essentially verification — confirming the equipment is installed and operates per specification. PQ (performance qualification) is the validation step — demonstrating the equipment/process consistently performs under real production conditions. Process validation as a whole spans both.
In medical devices, what is design verification vs design validation?
Design verification confirms design outputs meet design inputs (you built to spec). Design validation confirms the finished device meets user needs and intended use, under actual or simulated use conditions (you built the right device). Both are required under the device QMS.
Can you validate without verifying?
Not credibly. Validation assumes the individual elements already meet their specifications; if you never verified them, a successful validation run is luck, not evidence. Regulators expect verification to underpin validation.