Evaluation of mass measurements in accordance with the GUM

When the mass laboratory of DFM was created in 1989, harmonized principles for the evaluation of measurement uncertainty were being created based on a very simple principle endorsed by the CIPM: all uncertainties should be interpreted as the square root of variances (standard deviations) and should be combined and expressed as such. This paper describes how DFM has interpreted this principle for the calibration of mass standards and for the measurement of mass in general. The importance of reporting calibration results in a compact way that is easily propagated down the traceability chain is also discussed.