ISO/TS TECHNICAL SPECIFICATION 20612 First edition 2007-12-01 Water quality - Interlaboratory comparisons for proficiency testing of analytical chemistry laboratories Qualite de I'eau- Comparaisons interlaboratoires pour des essais de compétence de laboratoires de chimie analytique Reference number ISO/TS 20612:2007(E) @ ISO 2007 IHSunder Not for Resale ISO/TS 20612:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by IsO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHTPROTECTEDDOCUMENT @ISO2007 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either isO at the address below or IsO's memberbody in the country of the requester. ISO copyright office Case postale 56. CH-1211Geneva 20 Tel. + 4122 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland @ ISo 2007 - All rights reserved ed without license from IHS Not for Resale ISO/TS 20612:2007(E) Contents Page Foreword IV Introduction 1 Scope 2 Normative references 3 Terms and definitions 4 Symbols...... 5 Requirements relating to proficiency test provider 6 Participants.. 7 Proficiency test design 8 Execution of proficiencytests.. 9 Proficiency test evaluation. 10 Presentation of results... 15 11 Archiving and managing the results.. 15 Annex A (informative) Example of Q-method estimation principle.. Annex B (informative) Determination of repeatability standard deviation, Sr Annex C (informative) Example of evaluation method in Clause 9.... Annex D (informative) Example of variance function calculation (9.3).. 21 Bibliography 25 ili from IHS Not for Re ISO/TS 20612:2007(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies technicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeen established has the right to be represented on that committee. International organizations, governmental and International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2 The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In other circumstances, particularly when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of document: an isO working group and is accepted for publication if it is approved by more than 50 % of the members of the parent committee casting a vote; committeeandisacceptedforpublicationifitisapprovedby2/3ofthemembersofthecommitteecasting avote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is International Standard or be withdrawn. Attention is drawn to the possibility that some of the elements o