|
INTERNATIONAL ISO
STANDARD 4259-5
First edition
2023-12
Petroleum and related products —
Precision of measurement methods
and results —
Part 5:
Statistical assessment of agreement
between two different measurement
methods that claim to measure the
same property
Produits pétroliers et connexes — Fidélité des méthodes de mesure et
de leurs résultats —
Partie 5: Évaluation statistique de l'accord entre deux méthodes de
mesure différentes qui prétendent mesurer la même propriété
Reference number
© ISO 2023
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 member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: [email protected]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 3
5 Procedure overview .4
5.1 General requirements . 4
5.2 Additional requirements for PTP data . 5
5.2.1 General conditions . 5
5.2.2 Test on existence of extreme samples . 5
5.2.3 Test on distribution of lab results . 6
5.2.4 Comparison of precision . 7
5.3 Brief sequential steps of the procedure . 7
5.4 Flow diagram of the procedure . 9
6 Procedure .11
6.1 Sample mean and standard error . 11
6.1.1 General . 11
6.1.2 Computation of the means . 11
6.1.3 Calculation of standard errors . 11
6.2 Suitability of the data .12
6.2.1 Test on property variation .12
6.2.2 Correlation of the test methods .12
6.3 Bias correction selection statistics . 13
6.3.1 General .13
6.3.2 Class 0—No bias correction . 13
6.3.3 Class 1a—Constant bias correction . 13
6.3.4 Class 1b — Proportional bias correction . 14
6.3.5 Class 2 — Proportional and constant bias correction . 14
6.4 Selection of the appropriate bias correction class . 15
6.5 Confirming the normal distribution of weighted residuals . 16
6.6 Sample-specific biases . 17
7 Report .19
8 Confirmation of the correlation.19
Annex A (informative) Worked example using ILS data .21
Annex B (informative) Worked example using PTP data .33
Bibliography .48
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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 ISO document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes 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 had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO 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.
This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels
and lubricants from natural or synthetic sources, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 19, Gaseous and liquid fuels, lubricants and related
products of petroleum, synthetic and biological origin, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
A list of all parts in the ISO 4259 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
This document explains the statistical methodology for assessing the expected agreement between
two standardized test methods that purport to measure the same property of a material. Subsequently,
it is investigated whether a linear bias correction can significantly improve the expected agreement.
The degree of agreement is expressed as a between-methods reproducibility after a bias correction (if
necessary) has been applied.
The method uses numerical results from a set of samples that have been analysed independently using
both test methods by different laboratories. The variation associated with each test method result is
used for assessing the required bias correction.
Annexes A and B give worked out examples showing how the methodology is applied.
v
INTERNATIONAL STANDARD ISO 4259-5:2023(E)
Petroleum and related products — Precision of
measurement methods and results —
Part 5:
Statistical assessment of agreement between two different
measurement methods that claim to measure the same
property
1 Scope
This document specifies statistical methodology for assessing the expected agreement between two
test methods that purport to measure the same property of a material, and for deciding if a simple
linear bias correction can further improve the expected agreement.
This document is applicable for analytical methods which measure quantitative properties of petroleum
or petroleum products resulting from a multi-sample-multi-lab study (MSMLS). These types of studies
include but are not limited to interlaboratory studies (ILS) meeting the requirements of ISO 4259-1
or equivalent, and proficiency testing programmes (PTP) meeting the requirements of ISO 4259-3 or
equivalent.
The methodology specified in this document establishes the limiting value for the difference between
two results where each result is obtained by a different operator using different apparatus and two
methods X and Y, respectively, on identical material. One of the methods (X or Y) has been appropriately
bias-corrected to agree with the other in accordance with this practice. This limit is designated as the
between-methods reproducibility. This value is expected to be exceeded with a probability of 5 % under
the correct and normal operation of both test methods due to random variation.
NOTE Further conditions for application of this methodology are given in 5.1 and 5.2.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 4259-1, Petroleum and related products — Precision of measurement methods and results — Part 1:
Determination of precision data in relation to methods of test
ISO 4259-3, Petroleum and related products — Precision of measurement methods and results — Part 3:
Monitoring and verification of published precision data in relation to methods of test
ISO 4259-4, Petroleum and related products — Precision of measurement methods and results — Part 4:
Use of statistical control charts to validate 'in-statistical-control' status for the execution of a standard test
method in a single laboratory
3 Terms and definitions
For the purposes of this document, the terms and definitions in ISO 4259-1 and the following terms and
definitions apply.
ISO 4259-5:202
...