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True value and uncertainty in the GUM.

¹National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8910, USA.

Journal of Physics. Conference Series

|May 9, 2022

Summary

This summary is machine-generated.

The Guide to the Expression of Uncertainty in Measurement (GUM) operationalizes measurement uncertainty. Later JCGM documents, by focusing on coverage intervals, diverge from GUM by assuming a unique true value, which is often not applicable in metrology.

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Area of Science:

Metrology
Measurement Science

Background:

The Guide to the Expression of Uncertainty in Measurement (GUM) defines uncertainty operationally.
Joint Committee for Guides in Metrology (JCGM) documents introduced the concept of a coverage interval.
Coverage intervals assume a unique true value for the measurand.

Purpose of the Study:

To clarify the operational definition of measurement uncertainty as presented in the GUM.
To highlight the limitations of the JCGM's coverage interval concept for ordinary measurands.
To correct misunderstandings regarding the GUM's treatment of true values and uncertainty.

Main Methods:

Conceptual analysis of metrology documents.
Comparison of GUM and JCGM approaches to measurement uncertainty.
Examination of the applicability of 'coverage interval' in metrology.

Main Results:

The GUM's operational view of uncertainty is distinct from the pre-GUM concept of a coverage interval.
The JCGM's coverage interval is of limited utility for ordinary measurands, which often lack a unique true value.
Divergence in JCGM documents stems from misinterpretations of GUM concepts.

Conclusions:

The operational definition of uncertainty in the GUM remains crucial for practical metrology.
The JCGM's coverage interval concept is not universally applicable to all measurands.
Revisiting the foundational principles of the GUM is necessary to resolve current ambiguities in uncertainty representation.