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EURACHEM / CITAC Guide CG 4

Quantifying Uncertainty in Analytical Measurement
Third Edition

QUAM:2012.P1

EURACHEM/CITAC Guide

Quantifying Uncertainty in Analytical Measurement
Third Edition

Editors
S L R Ellison (LGC, UK) A Williams (UK)

Composition of the Working Group*
EURACHEM members A Williams Chairman S Ellison Secretary R Bettencourt da Silva W Bremser A Brzyski P Fodor R Kaarls R Kaus B Magnusson E Amico di Meane P Robouch M Rösslein A van der Veen M Walsh W Wegscheider R Wood P Yolci Omeroglu CITAC Representatives A Squirrell I Kuselman A Fajgelj
ILAC National Physical Laboratory of Israel IAEA Vienna UK LGC, Teddington, UK University of Lisbon, Portugal BAM, Germany Eurachem Poland Corvinus University of Budapest, Hungary Netherlands Measurement Institute, The Netherlands Eurachem Germany SP, Sweden Italy IRMM, EU EMPA St. Gallen, Switzerland Netherlands Measurement Institute, The Netherlands Eurachem IRE Montanuniversitaet, Leoben, Austria Food Standards Agency, UK Istanbul Technical University, Turkey

Acknowledgements
This document has been produced primarily by a joint EURACHEM/CITAC Working Group with the composition shown (right). The editors are grateful to all these individuals and organisations and to others who have contributed comments, advice and assistance. Production of this Guide was in part supported by the UK National Measurement System. CITAC Reference This Guide constitutes CITAC Guide number 4

Eurolab Representatives M Golze
BAM, Germany *Attending meetings or corresponding in the period 2009-2011

Quantifying Uncertainty

Contents

CONTENTS
FOREWORD TO THE THIRD EDITION 1. SCOPE AND FIELD OF APPLICATION 2. UNCERTAINTY 2.1. 2.2. 2.3. 2.4. 2.5. DEFINITION OF UNCERTAINTY UNCERTAINTY SOURCES UNCERTAINTY COMPONENTS ERROR AND UNCERTAINTY THE VIM 3 DEFINITION OF UNCERTAINTY 1 3 4 4 4 4 5 6 7 7 8 9 10 12 14 16 16 16 17 17 17 17 18 20 21 22 22 22 23 23 24 25 26 26 26 28

3. ANALYTICAL MEASUREMENT AND