Pass / Fail / Inconclusive Criteria for Inter-Laboratory Comparisons

Published

April 14, 2015

Author(s)

Blaza Toman, Bodo Mickan, Gerd Wubbeler, Olha Bodnar, Clemens Elster, John D. Wright

Abstract

Inter-laboratory comparisons use the best available transfer standards to check participants uncertainty analyses, identify underestimated uncertainty claims or measurement errors, and improve the global measurement system. For some measurands (e.g. flow) instability of the transfer standard can lead to an inconclusive comparison result. If the transfer standard uncertainty is large relative to a participating laboratorys uncertainty, the commonly used standardized degree of equivalence |En_i|less than or equal to}1 criterion does not always correctly assess whether a participant is working within its uncertainty claims. We show comparison results that demonstrate the problem and discuss the loss of explanatory power in terms of statistical hypothesis tests. We propose several criteria for assessing a comparison result as passing, failing, or inconclusive and investigate the behavior of En and alternative comparison measures for a range of d_i / u_{lab i} and u_TS / u_{lab i} values. Two of them (Criteria C and D) successfully discerned between passing, failing, and inconclusive comparison results for the cases we examined.

Proceedings Title

9th International Symposium on Fluid Flow Measurement (ISFFM)

Conference Dates

April 14-17, 2015

Conference Location

Arlington, VA, US

Pub Type

Conferences

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Keywords

Comparison, degree of equivalence, criteria, transfer standard, uncertainty

Citation

Toman, B. , Mickan, B. , Wubbeler, G. , Bodnar, O. , Elster, C. and Wright, J. (2015), Pass / Fail / Inconclusive Criteria for Inter-Laboratory Comparisons, 9th International Symposium on Fluid Flow Measurement (ISFFM), Arlington, VA, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=918285 (Accessed April 20, 2024)