Measurement calibration: a set of operations to determine, under specified conditions, the relationship between the measured value indicated by a measuring instrument or measurement system, or the value represented by a physical gauge or reference material, and the corresponding value reproduced by a standard. Calibration results can be given to the measured value, but also to determine the value of the correction value, calibration can also determine other metrological characteristics, such as the role of the influence of the amount of calibration results can be issued as a "calibration certificate" or "calibration report".
Measurement verification: verification and calibration of the same point is: all belong to the traceability of an effective and reasonable methods and means, the purpose is to achieve the traceability of the value.
The difference between the two:
1. Accreditation is a comprehensive assessment of the measurement characteristics of measuring instruments; and calibration is mainly to determine its value.
2. Accreditation of measuring instruments to make a qualified or unqualified conclusion; and calibration does not determine the qualification of measuring instruments.
3. Accreditation should be issued a certificate, stamped with the seal of inspection or notice of failure; while the calibration is issued by the calibration certificate or calibration report and reflect the error in value.
4. Accreditation based on the test procedures; and calibration based on the calibration specification / test procedures.
Reference: what is the difference between metrological verification and metrological calibration