Verification

Verification is a confirmation that an instrument or measurement system meets defined specifications. It differs from calibration in that verification produces a pass/fail result against established criteria, while calibration determines the actual measurement errors and associated uncertainties. Verification may be performed as part of a calibration process (when the as-found data is compared against tolerances) or as an independent check.

In practice, verification can range from a simple functional check to a comprehensive evaluation. Examples include checking a thermometer at the ice point, verifying a balance with a known check weight, or performing an intermediate check on a reference standard between scheduled calibrations. Intermediate verifications are a key element of ISO 17025 quality systems, providing evidence that equipment continues to perform acceptably between full calibrations.

For calibration management, verification serves as a risk-reduction tool. Regularly scheduled verifications between calibrations can catch drift or problems early, before they affect product quality. Verification results should be documented and trended, and out-of-specification verification results should trigger immediate investigation and recalibration. Many organizations establish a verification schedule that is more frequent than the calibration schedule, using simpler checks to maintain confidence in instrument performance.