A Survey of Key Comparisons A Survey of Design, Analysis, and Reporting of Results in Key Comparisons
Adriana Hornikova, William F. Guthrie
Key comparisons are international inter-laboratory studies used to establish the degree of equivalence between national measurement standards. These studies, carried out by National Metrology Institutes (NMIs), are time-consuming, but necessary to facilitate international trade. From the signing of the Mutual Recognition Arrangement (MRA) in 1999 through the end of 2004, 85 key comparisons in a wide range of metrological areas were completed and have results posted in the Key Comparison Database (KCDB) maintained by the BIPM in France and in the International Comparisons Database (ICDB) maintained by NIST in the U.S [1,2]. Supported by this large set of completed comparisons from the KCDB and the ICDB, an opportunity has arisen to study the methods that are being used to conduct key comparisons. This paper summarizes work on currently completed key comparisons and offers recommendations for the design, analysis, and interpretation of future comparisons.