ISO/FDIS 11929-2

Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation — Fundamentals and application — Part 2: Advanced applications

The ISO 11929 series specifies a procedure, in the field of ionizing radiation metrology, for the calculation of the "decision threshold", the "detection limit" and the "limits of the coverage interval" for a non-negative ionizing radiation measurand when counting measurements with preselection of time or counts are carried out. The measurand results from a gross count rate and a background count rate as well as from further quantities on the basis of a model of the evaluation. In particular, the measurand can be the net count rate as the difference of the gross count rate and the background count rate, or the net activity of a sample. It can also be influenced by calibration of the measuring system, by sample treatment and by other factors. ISO 11929 has been divided into four parts covering elementary applications in ISO 11929-1, advanced applications on the basis of the GUM Supplement 1 in this document, applications to unfolding methods in ISO 11929-3, and guidance to the application in ISO 11929-4. ISO 11929-1 covers basic applications of counting measurements frequently used in the field of ionizing radiation metrology. It is restricted to applications for which the uncertainties can be evaluated on the basis of the ISO/IEC Guide 98-3 (JCGM 2008). In Annex A of ISO 11929-1:2019 the special case of repeated counting measurements with random influences is covered, while measurements with linear analogous ratemeters are covered in Annex B of ISO 11929-1:2019. This document extends the former ISO 11929:2010 to the evaluation of measurement uncertainties according to the ISO/IEC Guide 98-3-1. It also presents some explanatory notes regarding general aspects of counting measurements and on Bayesian statistics in measurements. ISO 11929-3 deals with the evaluation of measurements using unfolding methods and counting spectrometric multi-channel measurements if evaluated by unfolding methods, in particular, for alpha- and gamma‑spectrometric measurements. Further, it provides some advice on how to deal with correlations and covariances. ISO 11929-4 gives guidance to the application of ISO 11929, summarizes shortly the general procedure and then presents a wide range of numerical examples. Information on the statistical roots of ISO 11929 and on its current development may be found elsewhere[30,31]. ISO 11929 also applies analogously to other measurements of any kind especially if a similar model of the evaluation is involved. Further practical examples can be found, for example, in ISO 18589[1], ISO 9696[2], ISO 9697[3], ISO 9698[4], ISO 10703[5], ISO 7503[6], ISO 28218[7], and ISO 11885[8]. NOTE A code system, named UncertRadio, is available for calculations according to ISO 119291 to ISO 11929-3. UncertRadio[27][28] can be downloaded for free from https://www.thuenen.de/en/fi/fields-of-activity/marine-environment/coordination-centre-of-radioactivity/uncertradio/. The download contains a setup installation file which copies all files and folders into a folder specified by the user. After installation one has to add information to the PATH of Windows as indicated by a pop‑up window during installation. English language can be chosen and extensive "help" information is available. . Another tool is the package ?metRology'[32] which is available for programming in R. It contains the two R functions ?uncert' and ?uncertMC' which perform the GUM conform uncertainty propagation, either analytically or by the Monte Carlo method, respectively. Covariances/correlations of input quantities are included. Applying these two functions within iterations for decision threshold and the detection limit calculations simplifies the programming effort significantly. It is also possible to implement this part of ISO 11929 in a spreadsheet containing a Monte Carlo add-in or into other commercial mathematics software.

Détermination des limites caractéristiques (seuil de décision, limite de détection et extrémités de l'intervalle élargi) pour mesurages de rayonnements ionisants — Principes fondamentaux et applications — Partie 2: Applications avancées

La série ISO 11929 spécifie une procédure applicable, dans le domaine de la métrologie des rayonnements ionisants, pour le calcul du «seuil de décision», de la «limite de détection» et des «limites de l'intervalle élargi» pour un mesurande de rayonnement ionisant non négatif, lorsque des mesurages par comptage sont effectués avec une présélection du temps ou du nombre d'impulsions. Le mesurande résulte d'un taux de comptage brut et d'un taux de comptage du bruit de fond ainsi que de grandeurs supplémentaires reposant sur un modèle d'évaluation. En particulier, le mesurande peut être le taux de comptage net défini comme la différence du taux de comptage brut et du taux de comptage du bruit de fond, ou l'activité nette d'un échantillon. Il peut également être influencé par l'étalonnage du système de mesure, par le traitement de l'échantillon et par d'autres facteurs. L'ISO 11929 a été scindée en quatre parties couvrant les applications élémentaires dans l'ISO 11929-1, les applications avancées reposant sur le Guide ISO/IEC 98-3-1 dans le présent document, les applications aux méthodes de déconvolution dans l'ISO 11929-3, et les recommandations d'application dans l'ISO 11929-4. L'ISO 11929-1 couvre les applications de base des mesurages par comptage souvent utilisées dans le domaine de la métrologie des rayonnements ionisants. Elle se limite aux applications pour lesquelles il est possible d'évaluer les incertitudes sur la base du Guide ISO/IEC 98-3 (JCGM 2008). L'Annexe A de l'ISO 11929-1:2019 traite du cas particulier des mesurages répétés par comptage avec des influences aléatoires, alors que l'Annexe B de l'ISO 11929-1:2019 couvre les mesurages avec des ictomètres analogiques linéaires. Le présent document étend l'ancienne ISO 11929:2010 à l'évaluation des incertitudes de mesure conformément au Guide ISO/IEC 98-3-1. Il contient également plusieurs notes explicatives concernant les aspects généraux des mesurages par comptage et les statistiques bayésiennes dans les mesurages. L'ISO 11929-3 traite de l'évaluation des mesurages en utilisant des méthodes de déconvolution ainsi que de l'évaluation des mesurages multicanaux spectrométriques par comptage en cas d'évaluation par des méthodes de déconvolution, en particulier pour les mesurages spectrométriques alpha et gamma. Elle fournit en outre des conseils pour le traitement avec des corrélations et des covariances. L'ISO 11929-4 fournit des recommandations pour l'application de l'ISO 11929, résume les grandes lignes de la procédure générale et présente ensuite un large éventail d'exemples numériques. Des informations relatives à l'origine des statistiques de l'ISO 11929 et à son stade de développement actuel peuvent être trouvées dans les Références [30] et [31]. L'ISO 11929 s'applique également de manière analogue à d'autres mesurages de tout type, notamment si un modèle d'évaluation similaire est concerné. D'autres exemples pratiques sont, par exemple, disponibles dans l'ISO 18589[1], l'ISO 9696[2], l'ISO 9697[3], l'ISO 9698[4], l'ISO 10703[5], l'ISO 7503[6], l'ISO 28218[7] et l'ISO 11665[8]. NOTE Un logiciel, baptisé UncertRadio, est disponible pour les calculs conformes aux ISO 119291 à ISO 11929-3. UncertRadio[27][28] peut être téléchargé gratuitement à l'adresse: https://www.thuenen.de/en/fi/fields-of-activity/marine-environment/coordination-centre-of-radioactivity/uncertradio/. Le logiciel disponible en téléchargement contient un fichier d'installation qui copie tous les fichiers et dossiers à un emplacement spécifié par l'utilisateur. Après l'installation, des informations doivent être saisies concernant le CHEMIN sous Windows qui a été indiqué dans une fenêtre contextuelle au cours de l'installation. La langue anglaise peut être choisie et des informations d'aide étendue sont proposées. Un autre outil est le progiciel «metRology»[32] qui est disponible pour la programmation en langage R. Il contient les deux fonctions R «uncert» et «uncertMC» qui assurent la propa

General Information

• Status: Not Published
• ICS: 17.240 - Radiation measurements
• Technical Committee: ISO/TC 85/SC 2 - Radiological protection
• Drafting Committee: ISO/TC 85/SC 2/WG 17 - Radioactivity measurements
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 07-Aug-2025
• Completion Date: 07-Aug-2025

Relations

• Consolidates: ISO 5148:2022 - Plastics — Determination of specific aerobic biodegradation rate of solid plastic materials and disappearance time (DT50) under mesophilic laboratory test conditions
• Effective Date: 07-Jan-2025
• Revises: ISO 11929-2:2019 - Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation — Fundamentals and application — Part 2: Advanced applications
• Effective Date: 07-Jan-2025

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/TC 85/SC 2
Determination of the characteristic
Secretariat: AFNOR
limits (decision threshold, detection
Voting begins on:
limit and limits of the coverage
interval) for measurements of
Voting terminates on:
ionizing radiation — Fundamentals
and application —
Part 2:
Advanced applications
Détermination des limites caractéristiques (seuil de décision,
limite de détection et extrémités de l'intervalle élargi)
pour mesurages de rayonnements ionisants — Principes
fondamentaux et applications —
Partie 2: Applications avancées
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 85/SC 2
Determination of the characteristic
Secretariat: AFNOR
limits (decision threshold, detection
Voting begins on:
limit and limits of the coverage
interval) for measurements of
Voting terminates on:
ionizing radiation — Fundamentals
and application —
Part 2:
Advanced applications
Détermination des limites caractéristiques (seuil de décision,
limite de détection et extrémités de l'intervalle élargi)
pour mesurages de rayonnements ionisants — Principes
fondamentaux et applications —
Partie 2: Applications avancées
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/CEN PARALLEL PROCESSING
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Quantities and symbols . 6
5 Summary of procedures for evaluating and reporting uncertainty and characteristic
limits . 8
6 Evaluation of a measurement on the basis of ISO/IEC Guide 98-3:2008/Suppl 1:2008 .11
6.1 Introduction and decisions to be made .11
6.2 General aspects concerning the measurand and the model of evaluation .11
6.3 Establishing probability distributions for the input quantities . 12
6.4 Propagating probability distributions .14
6.5 Evaluation of the primary measurement result . 15
6.6 Standard uncertainty associated with the primary measurement result . 15
7 PDF for an assumed true value of the measurand .15
8 Decision threshold, detection limit and assessments .16
8.1 Specifications .16
8.2 Decision threshold .16
8.3 Detection limit .17
8.4 Assessments . .18
9 Limits of the coverage interval .18
9.1 General Aspects .18
9.2 The probabilistically symmetric coverage interval .19
9.3 The shortest coverage interval .19
10 The best estimate and its associated standard uncertainty .20
11 Documentation .20
Annex A (normative) Measurements with low count numbers .22
Annex B (informative) Explanatory notes .24
Bibliography .38

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 documents 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 ISO/TC 85, Nuclear energy, nuclear technologies, and radiological
protection, Subcommittee SC 2, Radiological protection, in collaboration with the European Committee
for Standardization (CEN) Technical Committee CEN/TC 430, Nuclear energy, nuclear technologies, and
radiological protection, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This third edition of ISO 11929-2 replaces ISO 11929-2:2019, of which it constitutes a minor revision.
The main changes are as follows:
— correction of the internal references within the text;
— correction of the definitions of decision threshold (3.12) and the detection limit (3.13);
— editorial correction in Clause 7;
— correction of Formula (B.3);
— correction of Formula (B.17);
— correction of Formula (B.27);
— editorial correction in B.4.
A list of all the parts in the ISO 11929 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
Measurement uncertainties and characteristic values, such as the decision threshold, the detection limit and
limits of the coverage interval for measurements as well as the best estimate and its associated standard
measurement uncertainty, are of importance in metrology in general, and for radiological protection in
particular. The quantification of the uncertainty associated with a measurement result provides a basis for
the trust an individual can have in a measurement result. Conformity with regulatory limits, constraints or
reference values can only be demonstrated by taking into account and quantifying all sources of uncertainty.
Characteristic limits provide – in the end – the basis for deciding under uncertainty.
The ISO 11929 series provides characteristic values of a non-negative measurand of ionizing radiation.
It is also applicable for a wide range of measuring methods extending beyond measurements of ionizing
radiation.
The limits to be provided according to the ISO 11929 series for specified probabilities of wrong decisions
allow detection possibilities to be assessed for a measurand and for the physical effect quantified by this
measurand as follows:
— the “decision threshold” allows a decision to be made on whether or not the physical effect quantified by
the measurand is present;
— the “detection limit” indicates the smallest true quantity value of the measurand that can still be detected
with the applied measurement procedure; this gives a decision on whether or not the measurement
procedure satisfies the requirements and is therefore suitable for the intended measurement purpose;
— the “limits of the coverage interval” enclose, in the case of the physical effect recognized as present, a
coverage interval containing the true quantity value of the measurand with a specified probability.
Hereinafter, the limits mentioned are jointly called the “characteristic limits”.
NOTE According to ISO/IEC Guide 99:2007 updated by JCGM 200:2012 the term “coverage interval” is used here
instead of “confidence interval” in order to distinguish the wording of Bayesian terminology from that of conventional
statistics.
All the characteristic values are based on Bayesian statistics and on the ISO/IEC 98-3 Guide to the
Expression of Uncertainty in Measurement as well as on the ISO/IEC Guide 98-3:2008/Suppl 1:2008 and
ISO/IEC Guide 98-3:2008/Suppl 2:2011. As explained in detail in ISO 11929-2, the characteristic values are
mathematically defined by means of moments and quantiles of probability distributions of the possib
...

ISO /TC 85/SC 2/WG 17
Secretariat: AFNOR
Date: 2025-06-18xx
Determination of the characteristic limits (decision threshold,
detection limit and limits of the coverage interval) for measurements
of ionizing radiation — Fundamentals and applications — Part 2: Advanced
applicationsapplication —
Part 2:
Advanced applications
Détermination des limites caractéristiques (seuil de décision, limite de détection et extrémités de l'intervalle
élargi) pour mesurages de rayonnements ionisants — Principes fondamentaux et applications —
Partie 2: Applications avancées
FDIS stage
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
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO 2025 – All rights reserved
ii
Contents Page
Foreword . iv
Introduction . vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Quantities and symbols . 6
5 Summary of procedures for evaluating and reporting uncertainty and characteristic
limits . 8
6 Evaluation of a measurement on the basis of ISO/IEC Guide 98-3:2008/Suppl 1:2008 . 11
6.1 Introduction and decisions to be made . 11
6.2 General aspects concerning the measurand and the model of evaluation . 11
6.3 Establishing probability distributions for the input quantities . 12
6.4 Propagating probability distributions . 14
6.5 Evaluation of the primary measurement result . 15
6.6 Standard uncertainty associated with the primary measurement result . 15
7 PDF for an assumed true value of the measurand . 16
8 Decision threshold, detection limit and assessments . 16
8.1 Specifications . 16
8.2 Decision threshold . 17
8.3 Detection limit . 17
8.4 Assessments . 18
9 Limits of the coverage interval . 18
9.1 General Aspects . 18
9.2 The probabilistically symmetric coverage interval . 19
9.3 The shortest coverage interval . 19
10 The best estimate and its associated standard uncertainty . 20
11 Documentation . 21
Annex A (normative) Measurements with low count numbers . 22
Annex B (informative) Explanatory notes . 24
Bibliography . 38

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 documents 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/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 ISO/TC 85, Nuclear energy, nuclear technologies, and radiological protection,
Subcommittee SC 2, Radiological protection, in collaboration with the European Committee for
Standardization (CEN) Technical Committee CEN/TC 430, Nuclear energy, nuclear technologies, and
radiological protection, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This third edition of ISO 11929-2 replaces ISO 11929-2:2019, of which it constitutes a minor revision.
The main changes are as follows:
— — correction of the internal references within the text;
— — 3.12 and 3.13: correction of the definitions of decision threshold (3.12) and the detection limit (3.13);
— — Clause 7: editorial correction in 7;
— — B.2.1: correction of 0Formula (B.3);
— — B.3.1: correction of 0Formula (B.17);
— — B.2.2: correction of 0Formula (B.27));
— — B.4: editorial correction in B.4.
A list of all the parts in the ISO 11929 series can be found on the ISO website.
© ISO 2025 – All rights reserved
iv
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.
v
Introduction
Measurement uncertainties and characteristic values, such as the decision threshold, the detection limit and
limits of the coverage interval for measurements as well as the best estimate and its associated standard
measurement uncertainty, are of importance in metrology in general, and for radiological protection in
particular. The quantification of the uncertainty associated with a measurement result provides a basis for the
trust an individual can have in a measurement result. Conformity with regulatory limits, constraints or
reference values can only be demonstrated by taking into account and quantifying all sources of uncertainty.
Characteristic limits provide – in the end – the basis for deciding under uncertainty.
The ISO 11929 series provides characteristic values of a non-negative measurand of ionizing radiation. It is
also applicable for a wide range of measuring methods extending beyond measurements of ionizing radiation.
The limits to be provided according to the ISO 11929 series for specified probabilities of wrong decisions allow
detection possibilities to be assessed for a measurand and for the physical effect quantified by this measurand
as follows:
— — the “decision threshold” allows a decision to be made on whether or not the physical effect quantified
by the measurand is present;
— — the “detection limit” indicates the smallest true quantity value of the measurand that can still be
detected with the applied measurement procedure; this gives a decision on whether or not the
measurement procedure satisfies the requirements and is therefore suitable for the intended
measurement purpose;
— — the “limits of the coverage interval” enclose, in the case of the physical effect recognized as present, a
coverage interval containing the true quantity value of the measurand with a specified probability.
Hereinafter, the limits mentioned are jointly called the “characteristic limits”.
NOTE According to ISO/IEC Guide 99:2007 updated by JCGM 200:2012 the term “coverage interval” is used here
instead of “confidence interval” in order to distinguish the wording of Bayesian terminology from that of conventional
statistics.
All the characteristic values are based on Bayesian statistics and on the ISO/IEC 98-3 Guide to the Expression
of Uncertainty in Measurement as well as on the ISO/IEC Guide 98-3:2008/Suppl 1:2008 and ISO/IEC Guide
98-3:2008/Suppl 2:2011. As explained in detail in ISO 11929-2, the characteristic values are mathematically
defined by means of moments and quantiles of probability distributions of the possible measurand values.
Since measurement uncertainty plays an important part in the ISO 11929 series, the evaluation of
measurements and the treatment of measurement uncertainties are carried out by means of the general
procedures according to the ISO/IEC Guide 98-3 and to the ISO/IEC Guide 98-3:2008/Suppl 1:2008; see also
References [0[9] to [013].]. This enables the strict separation of the evaluation of the measurements, on the
one hand, and the provision and calculation of the characteristic values, on the other hand. The ISO 11929
[14 to 16]
series makes use of a theory of uncertainty in measurement based on Bayesian statistics (e.g. References
[0[17] to [022])]) in order to allow to take into account also those uncertainties that cannot be derived from
repeated or counting measurements. The latter uncertainties cannot be handled by frequentist statistics.
Because of developments in metrology concerning measurement uncertainty laid down in the ISO/IEC Guide
98-3, ISO 11929:2010 was drawn up on the basis of the ISO/IEC Guide 98-3, but using Bayesian statistics and
the Bayesian theory of measurement uncertainty. This theory provides a Bayesian foundation for the
[ [9]]
ISO/IEC Guide 98-3. Moreover, ISO 11929:2010 was based on the definitions of the characteristic values, 0,
[ [10]] [ [11]]
the standard proposal, 0, and the introducing article. 0. It unified and replaced all earlier parts of ISO
11929 and was applicable not only to a large variety of particular measurements of ionizing radiation but also,
in analogy, to other measurement procedures.
© ISO 2025 – All rights reserved
vi
Since the ISO/IEC Guide 98-3:2008/Suppl 1:2008 has been published, dealing comprehensively with a more
general treatment of measurement uncertainty using the Monte Carlo method in complex measurement
[ [12]]
evaluations. This provided an incentive for writing a corresponding Monte Carlo supplement 0 to
ISO 11929:2010 and to revise ISO 11929:2010. The revised ISO 11929 is also essentially founded on Bayesian
statistics and can serve as a bridge between ISO 11929:2010 and the ISO/IEC Guide 98-3:2008/Suppl 1:2008.
Moreover, more general definitions of the characteristic values (ISO 11929-2) and the Monte Carlo
computation of the characteristic values make it possible to go a step beyond the present state of
standardization laid down in ISO 11929:2010 since probability distributions rather than uncertainties can be
propagated. It is thus more comprehensive and extending the range of applications.
The ISO 11929 series, moreover, is more explicit on the calculation of the characteristic values. It corrects also
a problem in ISO 11929:2010 regarding uncertain quantiti
...