Total Risk of a False Decision on Conformity of a Multicomponent Material due to Measurement Uncertainty

Ilya Kuselman, Independent Consultant on Metrology, Modiin, Israel
Francesca Pennecchi, Quality Of Life, Istituto Nazionale Di Ricerca Metrologica, Turin, Italy
Ricardo J.N.B. da Silva, Faculdade De Ciências , Universidade De Lisboa, Lisboa, Portugal
D. Brynn Hibbert, School Of Chemistry, University Of New South Wales , Sydney, Australia

When conformity assessment for each component of a sample is successful, the total probability of a false decision (total consumer’s risk or producer’s risk) on the conformity of the sample as a whole may still be significant. It is shown that the total risk due to measurement uncertainty can be evaluated as a combination of the particular risks of conformity assessment of sample components. For a more complicate task, i.e. for a larger number of components of a sample under control, the total risk is larger. As an example, the total probability of false conforming (total consumer’s risk) is evaluated in customs control of the European completely denatured alcohols, where conformity assessment is performed by comparison of chemical analytical test results with the regulatory limits.