1. Select participating instruments and plan the comparison

Calibrations scheduled at fixed intervals (usually one year) cannot be adapted to an entire fleet of instruments. They inevitably entail two types of disadvantage:

• or they are too close together, resulting in unnecessary extra costs (over-quality);

• or they are spaced too far apart, resulting in metrological non-conformities likely to lead to "product" non-conformities.

This simple observation highlights the need to determine individual periodicities for each instrument, which C2I makes possible.