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Calibration, Verification, and Validation

Conducting measurements with a device that can be misinterpreted as calibration, validation, or verification.

Many laboratories have misinterpreted the term “verification” to avoid performing a calibration on a device used to support testing. The terms “calibration,” “verification,” and “validation” are quite different. They should not be confused with one another or used interchangeably.

Calibration Data Leads to Decisions

Simply put, a calibration produces data, nothing more. Once the calibration data is available, there are decisions to be taken.

A verification decision is typically taken each time an item is calibrated. Does the measurement data fall within specifications? Is the uncertainty sufficiently low to make this determination?

A validation decision is normally taken with a first-time calibration or the first time an item is used for a task. A secondary validation decision should be taken when the item does not meet all the specified limits as it may still be fit for purpose for some, but not all operations. An item may be identified for several purposes (tests) in a laboratory; an out-of-tolerance data point for one measurement parameter may not affect some of those tests.

In short, there are three steps: calibration as a first step produces measurement results, verification as a second step confirms results are within defined limits, and validation as a third step confirms fitness for purpose.

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