| Zugriffsnummer | 30007 |
| Dokumenttyp | Zeitschriftenartikel |
| Peer Review | unbekannt |
| Sprache | Englisch |
| Titel | Analysis of key comparison data: critical assessment of elements of current practice with suggested improvements |
| Autor(in); Institution |
Elster, Clemens; 8.4, Mathematische Modellierung und Datenanalyse, PTB-Berlin
Toman, Blaza; NIST, Statistical Engineering Division, Gaithersburg, MD, USA
|
| Quelle/Jahr | Metrologia: 50 (2013), 5, 549 - 555 |
| ISSN | 0026-1394 (PRINT) ; 1681-7575 (ONLINE) |
| DOI | |
| URL | |
| Verlag | Bristol [u.a.]: BIPM & IOP Publ. |
| Klassifikationscode | PACS: 06.20.Dk ; PACS: 02.50.-r |
| Freie Schlagworte | key comparisons ; CIPM-MRA ; Bayesian inference ; fixed effects model |
| Zusammenfassung | The degrees of equivalence can be viewed as possibly the main result in the analysis of key comparison data. Their specification as given in the CIPM MRA is discussed and critically assessed in this paper. We argue that there is an ambiguity in the definition and meaning of the (unilateral) degrees of equivalence. As a consequence of this ambiguity uncertainties quoted for (unilateral) degrees of equivalence may be questioned. The ambiguity can be avoided by identifying the quantities that are being estimated by the degrees of equivalence, and we propose a standard statistical model to do this. We then show that the degrees of equivalence are not a unique measure of consistency between the results and the underlying measurand when determined solely from the data. Prior knowledge or additional assumptions are needed for this purpose, and Bayesian methods are particularly suitable to handle that. However, such measures of consistency depend on the chosen additional assumptions and generally are not in accordance with the current CIPM MRA. Fortunately, quantifying consistency between the results and the underlying measurand is not necessary in order to assess equivalence between the laboratories. We show that on the basis of the (unambiguous) pairwise degrees of equivalence the laboratories can be grouped into equivalent subsets, the largest of which may be chosen to select those laboratories whose CMCs are then viewed as validated. |
