Measurement problems of conformity assessment in the quality infrastructure

A brief description of the problems that arise in the measurement problems of assessing compliance with established requirements in the quality infrastructure is given, including in connection with the requirements of ISO/IEC 17025:2017(E) “General requirements for the competence of testing and calibration laboratories” for documenting and applying decision-making rules for determinative and control tests, taking into account possible risks. These problems are conventionally divided into two groups: problems of methods for solving measurement problems, on which discussions are still ongoing, and problems of conformity assessment procedures, for which the experience of control theory can be used. The first group includes the problems of uncertainty and precision of measurement, the inadequacy of measurement equations in the indirect measurement method, the loss of the property of freedom from distribution by the criteria of agreement in the statistical verification of complex hypotheses, the exclusion of outliers in measurement protocols and terminological contradictions. It is shown that the measurement tasks of assessing compliance with established requirements in the quality infrastructure can be formulated as typical problems of the theory of control. Therefore, the second group consists of problems that can be solved by methods for determining the completeness of control, setting tolerance limits for controlled parameters, and selecting the confidence level. Then it becomes possible to assess the risks of statistical assumptions, false positive and false negative decisions about compliance with established requirements based on mathematical models of control objects.