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Simple Guide for Evaluating and Expressing the Uncertainty of NIST Measurement Results



Antonio M. Possolo


The "Simple Guide" supplements, but does not replace NIST Technical Note 1297, whose techniques for uncertainty evaluation may continue to be used when there is no compelling reason to question their applicability and fitness for purpose, as enunciated in a grandfathering clause. The "Simple Guide" proposes widening the meaning of "measurement", characterizes measurement uncertainty probabilistically, describes measurement models and discusses their inputs, presents bottom-up and top-down approaches to uncertainty evaluation, explains how measurement uncertainty may be evaluated for measurement equations and for observation equations, and reviews ways of expressing measurement uncertainty. The "Simple Guide" includes many examples of uncertainty evaluations worked out in detail, drawn from a very diverse collection of areas of application of measurement science.
Technical Note (NIST TN) - 1900
Report Number


measurement uncertainty, measurement model, measurement equation, observation equation, top- down, bottom-up, input, output, probability distribution, statistical method, Bayesian, Monte Carlo, NIST Uncertainty Machine, bootstrap, coverage region, coverage probability.


Possolo, A. (2015), Simple Guide for Evaluating and Expressing the Uncertainty of NIST Measurement Results, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed April 20, 2024)
Created November 4, 2015, Updated June 2, 2021