Stability Tests in the Process of Organization of Interlaboratory Comparison

Success in programs of interlaboratory comparisons is based on two basic pillars. In addition to the inseparable share of the laboratory and the quality of the activities performed, the quality of the organized program of interlaboratory comparison also affects the final success. Organizing tests is a time consuming process. It includes several important stages that precede the laboratory's participation in the program itself. One of the most important stages is the selection of an object suitable for the purpose of comparative measurements. One of the criteria for selecting an interlaboratory comparison item is its stability. The article focuses on the basis of ILC, the causes of unsuccessful results, areas where a stability test is required and where not, and one of the possible approaches to checking the stability of a measuring instrument. The proposed approach is defined by the measurement model, described by methodological steps and was applied in practice, where the results were evaluated and analysed in the discussion. In conclusion, it can be stated that the proposed approach is particularly suitable for areas where it is possible to obtain a relatively large amount of data by automating the collection, as it is an application of statistical approaches. Even with this approach, cost-effectiveness must not be forgotten, with an impact on the final price for participation in the ILC. The situation therefore requires the search for optimal solutions in terms of the degree of risk and the cost of stability tests.