A POSSIBLE IMPROVEMENT TO THE ISO-GUM

G. Fanti

Abstract

The ISO-GUM (Guide for Uncertainty Measurement) is a milestone in the history of uncertainty analysis, but practical procedures have still not been completely defined. In order to clarify some operative aspects, this paper proposes a practical improvement to the GUM, presenting a step-by-step procedure that illustrates how to evaluate uncertainty, developing analysis in parallel with the measurement process of the parameter. Following the ISO-GUM baseline, the proposed procedure is subdivided into: a) modelling stage: before designing a measurement chain suitable for a certain parameter, the modelling of the physical system under analysis and of the measurement system used to acquire that parameter is examined; b) instrument design stage: the metrological characteristics of each component of the measurement chain are analysed, also considering the traceability of reference samples; c) advanced stage: all previously detected components are combined with those from test operating conditions, e.g., effects of time, interfering and modifying disturbances; d) correction stage: the systematic effects are accounted for; e) indirect measurement stage: uncertainty propagated to the result of an indirect measurement is obtained by means of sensitivity indexes.

Keywords

uncertainty, measurement, procedure

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IMEKO-WC-2000-UNC-P504.pdf

DOI

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