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An Interpretation of the Guide to the Expression of Uncertainty in Measurement



Raghu N. Kacker


The Guide to the Expression of Uncertainty in Measurement (GUM) is intended for all scientific and technological measurements in science, engineering, commerce, industry, and regulation. So the GUM must have a clear interpretation. But it mixes up concepts from frequentist and Bayesian statistics in ambiguous ways. Therefore, as presented, the GUM is not clear and liable to be applied in more than one way, leading to more than one way of expressing uncertainty in measurement. This paper attempts to present a clear and coherent interpretation of the GUM and proposes a simple and widely applicable approach to construct expanded uncertainty intervals. Our hope is that the clarifications and the viewpoints presented here will promote a more consistent use of the GUM and facilitate its application to situations not explicitly covered in the original document.
Special Publication (NIST SP) - 500-244
Report Number


Bayesian analysis, expanded uncertainty, frequentist statistics, metrologoy, statistics, uncertainty


Kacker, R. (2000), An Interpretation of the Guide to the Expression of Uncertainty in Measurement, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD (Accessed March 2, 2024)
Created May 1, 2000, Updated October 16, 2008