Measurement comparisons: A tool to guarantee the reliability of measurement systems and of high-tech industry

Measurement comparisons or inter-laboratory comparisons (ILCs) are the main tool to establish the measurements' compatibility between different laboratories or different measurement methods. Therefore, they are a mean to establish the equivalence of national standards maintained at the National Measurement Institutes (NMI), the correctness of the measurement traceability transfer from NMIs to secondary calibration laboratories, of their accreditation processes and the suitability of their operators' competence and equipment. ILCs' role is then of strategic importance as the NMIs and the secondary calibration laboratories lay at the top of a chain representing the measurement system of each modern industrialized country. Each step of this chain has to be under control to assure that final products (or product parts) could eventually assembled with other parts made in other countries. At the level of NMI, high-level key comparisons are carried out to compare national standards while at the national level, ILCs between NMIs and secondary laboratories are useful to verify the capabilities of these laboratories. Secondary laboratories calibrate standards and instruments of lower level and industrial laboratories. As these last ones support directly the industrial and manufacturing sectors, it can be concluded that ILCs are the main tool to assure the reliability of measurement systems and thus a strategic support for high-tech modern industry.