Abstract
Accredited technical laboratories are responsible not only for conducting certification tests to ensure the quality of construction products, but also for participating in continuous quality control during facility construction. An important factor in ensuring the validity of results is the expertise of the experts performing the tests. This article describes the requirements for accredited laboratories and providers of qualification verification for interlaboratory comparison tests. It also discusses the organization of these tests and the options for assigning values to construction industry testing laboratories and qualification verification providers. An algorithm for calculating the robust arithmetic mean to determine the assigned value is presented. Recommended methods for determining the assigned value are considered, depending on the product and the parameter being determined, as well as the number of samples required and the possibility for further use. Examples of determining the assigned value using different methods of calculation are provided. Recommendations are made on choosing the method for determining the assigned value based on the specific nature of tests and the characteristics of construction industry equipment.