Statistical analysis of key comparison and inter-laboratory experiments is required to produce an estimate of the measurand called a reference value and further, measures of equivalence of the participating laboratories. Methods of estimation of the reference value have been proposed that rest on the idea of finding a so-called consistent subset of laboratories, that is, eliminating outlying participants. In this paper we propose an alternative statistical model, one that accommodates all of the participants data and incorporates the dispersion among the laboratories into the total uncertainty of the various estimates. This model recognizes the fact that the dispersion of values between laboratories often is substantially larger than the measurement uncertainties provided by the participating laboratories. We illustrate the method on data from key comparison CCL-K1.
Proceedings Title: Conference on Advanced Mathematical and Computational Tools in Metrology and Testing
Conference Dates: June 23-25, 2008
Conference Location: Paris, -1
Pub Type: Conferences