"Calibration" in isotopic measurements

The meaning of calibration in general and in the field of isotopic measurem ents in particular is described, stressing the fundamental difference betwe en calibration as an aim and tools to achieve calibration. The role of prop er uncertainty budgeting as a prerequisite for establishing a "calibrated" measurement is explained. It leads to the recommendation that the quality o f the uncertainty statement should be heavily weighed when ranking or judgi ng "calibrated" isotopic measurement results evaluated by the Commission on Atomic Weight and Isotopic Abundances. (C) 2000 Elsevier Science B.V.