Important Terms


Determination of the relation between the measurement results of a measuring instrument/device (or the values represented by a material measure or a reference material) and the associated quantity values provided by a measurement standard under specified conditions. Calibration should not be confused with adjustment of a measuring instrument. A Calibration is valid only for the moment of calibration. Unlike verification it cannot make long-term forecasts.


The adjustment is a set of operations carried out on a measuring system so that it provides prescribed indications corresponding to given values of a quantity to be measured. The given values are preset either by a more accurate measuring instrument or by known material properties. Then the measuring instrument is aligned i.e. with an adjusting screw. So an adjustment necessitates an intervention signifying a permanent change of the measuring instrument.


Determination of one or more characteristic values of a certain material, product or process according to a defined method.

Conformity assessment

Systematic examination of the extent to which a product, a process or a service complies with predefined requirements. The requirements for verifications are regulated by law. In this sense, verification is a conformity assessment.


The quality testing of a measuring instrument regulated by law. Verification consists of metrological examination and stamping. The metrological examination assesses the conformity of the measuring instrument with the verification requirements, i.e. whether it complies with the requirements for construction and metrological characteristics and whether it adheres to the limits of error (maximal permissible errors on verification). Stamping should certify the conformity for the duration of the mandatory interval for subsequent verification. All measuring instruments subject to mandatory verification are listed in the Metrology Act.


Property of a measurement result or value of a standard, whereby the result can be related to suitable standards by an unbroken chain of comparison measurements indicating the measurement uncertainty. Traceability is achieved by the use of calibrated measuring instruments or reference material. Verification can also be regarded as a means to traceability.