Assessing uncertainty in measurement

Abstract

In 1993 the International Organization for Standardization (ISO), in cooperation with several other international organizations, issued Guide to the Expression of Uncertainty in Measurement in order to establish, and standardize for international use, a set of general rules for evaluation and expressing uncertainty in measurement. The ISO recommendation has been of concern to many statisticians because it appears to combine frequentist performance measures and indices of subjective distributions in a way that neither frequentists nor Bayesians can fully endorse. The purpose of this review of the ISO Guide is to describe the essential recommendations made in the Guide, then to show how these recommendations can be regarded as approximate solutions to certain frequentist and Bayesian inference problems. The framework thus provided will, hopefully, allow statisticians to develop improvements to the ISO recommendations (particularly in the approximations used), and also better communicate with the physical science researchers who will be following the ISO guidelines.