IEC ISo Guide 98-1 Guide to the expression of Second edition 2024-02 uncertainty in measurement - Part 1: Introduction Guide pour I'expression de I'incertitude de mesure - Partie 1: Introduction A Referencenumber ISO/IEC Guide 98-1:2024(en) @ ISO/IEC 2024 IS0/IEC Guide 98-1:2024(en) COPYRIGHT PROTECTED DOCUMENT @ IS0/IEC 2024 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or Iso's memberbody inthe country oftherequester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 0111 Email: [email protected] Website: www.iso.org Published in Switzerland @ IS0/IEC 2024 - All rights reserved ii IS0/IEC Guide 98-1:2024(en) ISO/IEC Foreword ISo (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. IsO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of documentshouldbenoted.ThisdocumentwasdraftedinaccordancewiththeeditorialrulesoftheIsO/EC Directives, Part 2 (see www.iso.org/directives or www.iec.ch/members experts/refdocs). IsO and IEC draw attention to the possibility that the implementation of this document may involve the use of (a) patent(s). IsO and IEC take no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, IsO and IEC had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautionedthatthismaynotrepresentthelatestinformation,whichmaybeobtainedfromthepatentdatabase available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement. For an explanation of the voluntary nature of standards, the meaning of IsO specific terms and expressions related to conformity assessment, as well as information about Iso's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www.iso.org/iso/foreword.html In the IEC, see www.iec.ch/understanding-standards. This document was prepared by Working Group 1 of the Joint Committee for Guides in Metrology (as JCGM GUM-1:2023) and was adopted by the national bodies of ISO and IEC. This second edition cancels and replaces the first edition (IS0/IEC Guide 98-1:2009), which has been technically revised. The main changes are as follows: the document has been redrafted as an introduction to the revised ISO/IEC Guide 98 series; most conceptual and technical aspects have been removed. A list of all parts in the ISO/IEC Guide 98 series can be found on the ISO and IEC websites. Given that this document is identical in content to JCGM GUM-1:2023, the decimal symbol is a point on the line. Annex ZZ has been appended to provide a list of corresponding ISO/IEC Guides and JCGM guidance documents for which equivalents are not giv