Processing Dependent Systematic Contributions to Measurement Uncertainty

In the measurement field, the correlation of two uncertainty contributions is a form of probabilistic association that can significantly affect the final uncertainty associated to the measurement result. The Guide to the expression of uncertainty in measurement recommends a mathematical approach to deal with correlated random contributions to measurement uncertainty. A similar kind of association, or dependence, can characterize also different systematic contributions to uncertainty and should be taken into account when evaluating their effect on the final measurement uncertainty. This paper discusses a new approach to handle such systematic contributions when they are represented by symmetric possibility distributions (PDs) of the same shape. This method allows one to build the joint PD of two systematic contributions, both dependent and independent, and propagate them through a generic measurement function.