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Inter-Lab Comparison (ILCs)

CIPM MRA defines the technical basis of the arrangement as a set of results obtained over the course of time through scientific key comparisons carried out by the Consultative Committees of the CIPM (CCs),  the BIPM and the regional metrology organizations (RMOs), and published by the BIPM and maintained in the KCDB.

The key comparisons are essentially of two types:

1. CIPM key comparisons, of international scope, are carried out by those participants having the highest level of skills in the measurement involved, and are restricted to laboratories of Member States. The CIPM key comparisons deliver "the reference value" for the chosen key quantity;
2. RMO key comparisons, of regional scope, are organized at the scale of a region (though they may include additional participants from other regions) and are open to laboratories of Associates as well as Member States. These key comparisons deliver complementary information without changing the reference value.

GULFMET key comparison

GULFMET key comparison is a key comparison executed in the framework of GULFMET as a regional metrology organization (RMO).

Key comparison reference value

The key comparison reference value is the reference value resulting from the measurements taken in a CIPM key comparison, accompanied by its uncertainty (normally the standard uncertainty). Only CIPM key comparisons (carried out by a Consultative Committee or the BIPM) result in a key comparison reference value.

For a key comparison carried out by GULFMET (GULFMET key comparison) the link to the key comparison reference value is obtained by reference to the results from those institutes which have also taken part in the CIPM key comparison.