Role of measurement uncertainty in conformity assessment

Abstract

Conformity assessment, focused on risks quantification, evolved from being binary to being probabilistic. In fact, new methods described by the standard ISO CEI guide 98-4 [1] and FD X 07-039 [2] show how measurement uncertainty is integrated in the conformity assessment (FD X 07-039 : “Role of measurement uncertainty in conformity assessment – implementation of NF ISO/IEC Guide 98-4 – illustration through industrial case studies”). In such a probabilistic framework, the conformity assessment relies on two quantities: the measurement with its related uncertainty and the measurand prior knowledge. Both quantities are combined statistically to determine measurand posterior knowledge, and to quantify a global or specific risks either for the producer or the consumer. The standard also defines how integrating those two quantities improves the reliability of decisions based on measurements. This work will first present a clarification of the probabilistic approach described by the FD X07-039. Then, the measurand prior knowledge use will be explained. Finally, future metrology applications caused by such an approach will be listed.