The “Guide to the Expression of Uncertainty in Measurement” (GUM) is an extremely important document. It unifies methods for calculating measurement uncertainty and enables the consistent interpretation and comparison of measurement results regardless of who and where obtained these measurements. Since the document was published in 1995, it has been realized that its recommendations do not properly address an important class of measurements, namely, non-linear indirect measurements. This drawback prompted the initiation of the revision of GUM in the Working Group 1 of the Joint Committee for Guides in Metrology, which commenced in October 2006. The upcoming revision of GUM provides the metrological community with an opportunity to improve this important document, in particular, to reflect developments in Metrology that have occurred since the GUM publication in 1995. Thus, a discussion of the directions for this revision is important and timely. By identifying several shortcomings of the GUM and proposing directions for its improvement, we hope this article will contribute to this discussion.
metrology, measurement, inaccuracy, uncertainty, error