Laboratory Effects Models for Interlaboratory Comparisons

Published

June 16, 2009

Author(s)

Blaza Toman, Antonio M. Possolo

Abstract

Statistical analysis of inter-laboratory comparisons (e.g. Key Comparisons, Supplemental Comparisons) 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 CCQM-K25.

Citation

Accreditation and Quality Assurance

Volume

14

Issue

10

Pub Type

Journals

Keywords

Statistical analysis, key comparisons, reference value, uncertainty.

Citation

Toman, B. and Possolo, A. (2009), Laboratory Effects Models for Interlaboratory Comparisons, Accreditation and Quality Assurance (Accessed December 5, 2024)