Spreadsheet for evaluation of global risks in conformity assessment of a multicomponent material or object

A user-friendly MS-Excel spreadsheet is developed for evaluation of global consumer's and producer's risks in conformity assessment of chemical composition of a multicomponent material or object, when up to four component concentrations are under control. These risks are probabilities of incorrect conformity decisions related to a material batch (lot or similar) randomly drawn from a statistical population of such batches. The probabilities characterize the material quality globally, allowing the prediction of false decisions on conformity of a future batch, based on the future measurement results. The spreadsheet program evaluates risks using Monte Carlo simulations. As input data, the following need to be provided to the software: parameters of normal or lognormal distribution of actual (true') values of the component concentrations (prior distribution); parameters of the distribution of measurements results at the actual value of the component concentration (likelihood function); and correlation matrices for couples of the actual components' concentrations under control and also for corresponding measurement results. The spreadsheet is validated by comparison of the risk estimates with those calculated in R programing environment by numerical integration of the relevant analytical formulae. The developed Excel file and a demonstration videos of its use are available as electronic supplementary material.