Linking the Results of CIPM and RMO Key Comparisons With Linear Trends

Area of Science:

• Metrology
• Statistical Analysis
• Electrical Measurements

Background:

• Interlaboratory comparisons are crucial for assessing measurement capabilities of National Metrology Institutes (NMIs).
• Linking results from separate comparisons is challenging, especially when NMIs do not participate in the same studies.
• Existing methods may not adequately connect disparate datasets for establishing equivalence.

Purpose of the Study:

• To propose a statistical approach for linking results of interlaboratory comparisons.
• To establish degrees of equivalence and their uncertainties between NMIs that have not shared common comparisons.
• To demonstrate the application of this method to specific resistance measurement comparisons.

Main Methods:

• Development of a statistical framework to connect linear trends in interlaboratory comparison data.
• Application to scenarios with identical nominal values or magnitudes of measured quantities.
• Calculation of degrees of equivalence and associated uncertainties for linked NMIs.

Main Results:

• Successfully established degrees of equivalence between NMIs involved in the CCEM-K2 and SIM.EM-K2 resistance comparisons.
• Demonstrated the method's applicability for linking comparisons at the 1 GΩ resistance level.
• Quantified the uncertainties associated with the established degrees of equivalence.

Conclusions:

• The proposed statistical approach provides a robust method for linking independent interlaboratory comparisons.
• This enables a more comprehensive assessment of metrological equivalence across different NMIs and comparison series.
• The method enhances the consistency and reliability of international measurement comparisons, particularly for electrical resistance.