Interlaboratory comparison as a source of information about the problem

Abstract

Methods of evaluation of interlaboratory comparison results are prescribed by ISO standards. Ruler is probably one of the most widely used length measuring instrument in the world. For laboratories that plan to be accredited for the calibration of Ruler, the acquisition of a specialized Measuring bench is not economically feasible. Confidence in the measured result depends on the measurement uncertainty, and where deficiencies are observed, the values that contribute to the measurement uncertainty should be investigated. This paper describes an interlaboratory comparison for a small number of laboratories on the example of a Measuring bench for calibrating Ruler and indicates the procedure for problem identification; diagnosis of causes; consideration of solutions; initiation of action for improvement and monitoring of the results of applied solutions. The authors documented the problem and listed the elements that contributed to "Unsatisfactory" result in interlaboratory comparisons. They described the actions they took to overcome the "Unsatisfactory" result, analyzed whether the proposed solutions led to "Satisfactory" result and took actions accordingly. The paper presents the results of the international interlaboratory comparison, which are a confirmation of the competence of the personnel, measuring calibration equipment and calibration method.