SIST EN ISO 11929-1:2021
(Main)Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 1: Elementary applications (ISO 11929-1:2019)
Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 1: Elementary applications (ISO 11929-1:2019)
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 this document, advanced applications on the basis of the ISO/IEC Guide 3-1 in ISO 11929-2, applications to unfolding methods in ISO 11929-3, and guidance to the application in ISO 11929-4.
This document 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, the special case of repeated counting measurements with random influences is covered, while measurements with linear analogous ratemeters are covered in Annex B.
ISO 11929-2 extends the former ISO 11929:2010 to the evaluation of measurement uncertainties according to the ISO/IEC Guide 98-3-1. ISO 11929-2 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 the ISO 11929 series, 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[33][34].
The ISO 11929 series 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 11665[8].
NOTE A code system, named UncertRadio, is available for calculations according to ISO 11929-1 to ISO 11929-3. UncertRadio[31][32] can be downloaded for free from https://www.thuenen.de/de/fi/arbeitsbereiche/meeresumwelt/leitstelle-umweltradioaktivitaet-in-fisch/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.
Bestimmung der charakteristischen Grenzen (Erkennungsgrenze, Nachweisgrenze und Grenzen des Überdeckungsintervalls) bei Messungen ionisierender Strahlung - Grundlagen und Anwendungen - Teil 1: Elementare Anwendungen (ISO 11929-1:2019)
Die Normenreihe ISO 11929 legt im Bereich der Metrologie ionisierender Strahlung ein Verfahren zur Berechnung der „Erkennungsgrenze“, der „Nachweisgrenze“ und der „Grenzen des Überdeckungsintervalls“ für eine nicht-negative Messgröße der ionisierenden Strahlung bei Messungen mit Zeit- und Impulsvorwahl fest. Das Messergebnis ergibt sich aus den Ergebnissen von Messungen einer Bruttozählrate und einer Null-effektzählrate sowie weiteren Größen aufgrund eines Modells der Auswertung. Insbesondere kann die Mess-größe die Nettozählrate als Differenz der Bruttozählrate und der Nulleffektzählrate oder die Nettoaktivität einer Probe sein. Sie kann auch durch Kalibrierung der Messeinrichtung, Probenbehandlung und andere Faktoren beein¬flusst sein.
ISO 11929 ist in vier Teile aufgeteilt: elementare Anwendungen in diesem Dokument, fortgeschrittene Anwendungen auf der Grundlage von ISO/IEC Guide 98-3-1 in ISO 11929-2, Anwendungen auf Entfaltungs-methoden in ISO 11929-3 und Anleitungen zur Anwendung in ISO 11929-4.
Dieses Dokument behandelt elementare Anwendungen zählender Messungen, wie sie häufig im Bereich der Metrologie ionisierender Strahlung auftreten werden. Es beschränkt sich auf Anwendungen, bei denen die Unsicherheiten auf der Grundlage des ISO/IEC Guide 98-3 (JCGM 2008) ermittelt werden können. In Anhang A wird der spezielle Fall wiederholter zählender Messungen mit zufälligen Einflüssen und in Anhang B werden Messungen mit linearen analogen Ratemetern behandelt.
ISO 11929-2 erweitert die frühere ISO 11929:2010 um die Auswertung von Messungen, bei denen die Mess-unsicherheiten nach ISO/IEC Guide 98-3-1 ermittelt werden. ISO 11929-2 enthält außerdem Erläuterungen zu allgemeinen Aspekten zählender Messungen und zur Anwendung der Bayes-Statistik auf Messungen.
ISO 11929-3 behandelt die Auswertung von Messungen mit Hilfe von Entfaltungsverfahren und zählende Vielkanalmessungen, falls sie mit Entfaltungsmethoden ausgewertet werden, insbesondere für alpha- und gamma-spektrometrische Messungen. Außerdem gibt ISO 11929-3 Anleitungen, wie mit Korrelationen und Kovarianzen zu verfahren ist.
ISO 11929-4 gibt nach einer kurzen Darstellung des Verfahrens mit einer Fülle von numerischen Beispielen Anleitungen zur Anwendung der Normenreihe ISO 11929. Informationen über die statistischen Grundlagen von ISO 11929 und ihrer aktuellen Entwicklung können an anderer Stelle gefunden werden [33], [34].
Sinngemäß gilt die Normenreihe ISO 11929 auch bei anderen Messungen gleich welcher Art, wenn dasselbe Modell der Auswertung angewendet wird. Weitere praktische Beispiele können anderen ISO-Normen entnom-men werden, z. B. ISO 18589 [1], ISO 9696 [2], ISO 9697 [3], ISO 9698 [4], ISO 10703 [5], ISO 7503 [6], ISO 28218 [7], und ISO 11665 [8].
ANMERKUNG Ein Programmpaket namens UncertRadio ist für Berechnungen nach ISO 11929-1 bis ISO 11929-3 ver¬fügbar. UncertRadio [31], [32] kann unter https://www.thuenen.de/de/fi/arbeitsbereiche/meeresumwelt/leitstelle-umwelt¬radioaktivität-in-fisch/uncertradio/ kostenfrei heruntergeladen werden. Der Download enthält eine Installationsdatei, die alle Dateien in einen vom Benutzer spezifizierten Ordner kopiert. Nach der Installation ist noch eine Information, die wäh¬rend der Installation durch ein Pop-up-Fenster angezeigt wird, zum „PFAD“ von Windows hinzuzufügen. Es kann die eng¬lische Sprache gewählt werdenN2 und es ist eine ausführliche „Hilfe“-Information verfügbar.
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 1: Applications élémentaires (ISO 11929-1:2019)
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 le présent document, les applications avancées reposant sur le Guide ISO/IEC 3-1 dans l'ISO 11929-2, les applications aux méthodes de déconvolution dans l'ISO 11929-3, et les recommandations d'application dans l'ISO 11929-4.
Le présent document couvre les applications de base des mesurages par comptage souvent utilisés dans le domaine de la métrologie des rayonnements ionisants. Il 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 traite du cas particulier des mesurages répétés par comptage avec des influences aléatoires, alors que l'Annexe B couvre les mesurages avec des ictomètres analogiques linéaires.
L'ISO 11929-2 étend l'ancienne ISO 11929:2010 à l'évaluation des incertitudes de mesure conformément au Guide ISO/IEC 98-3-1. L'ISO 11929-2 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 la série 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 [33][34].
La série ISO 11929 s'applique également de manière analogue à d'autres mesurages de tout type, notamment si un modèle d'évaluation similaire est concerné. Des exemples pratiques complémentaires peuvent être trouvés, par exemple, 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 11929-1 à ISO 11929-3. UncertRadio[31][32] peut être téléchargé gratuitement à l'adresse: https://www.thuenen.de/de/fi/arbeitsbereiche/meeresumwelt/leitstelle-umweltradioaktivitaet-in-fisch/uncertradio/. Le logiciel disponible en téléchargement contient un fichier d'installation qui copie tous les fichiers et dossiers
Ugotavljanje karakterističnih mej (odločitveni prag, zaznavanje meje in omejitev intervala pokritja) pri meritvah ionizirnega sevanja - Osnove in uporaba - 1. del: Osnovne aplikacije (ISO 11929-1:2019)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 11929-1:2021
01-april-2021
Ugotavljanje karakterističnih mej (odločitveni prag, zaznavanje meje in omejitev
intervala pokritja) pri meritvah ionizirnega sevanja - Osnove in uporaba - 1. del:
Osnovne aplikacije (ISO 11929-1:2019)
Determination of the characteristic limits (decision threshold, detection limit and limits of
the coverage interval) for measurements of ionizing radiation - Fundamentals and
application - Part 1: Elementary applications (ISO 11929-1:2019)
Bestimmung der charakteristischen Grenzen (Erkennungsgrenze, Nachweisgrenze und
Grenzen des Überdeckungsintervalls) bei Messungen ionisierender Strahlung -
Grundlagen und Anwendungen - Teil 1: Elementare Anwendungen (ISO 11929-1:2019)
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 1: Applications élémentaires (ISO 11929-1:2019)
Ta slovenski standard je istoveten z: EN ISO 11929-1:2021
ICS:
17.240 Merjenje sevanja Radiation measurements
SIST EN ISO 11929-1:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 11929-1:2021
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SIST EN ISO 11929-1:2021
EN ISO 11929-1
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2021
EUROPÄISCHE NORM
ICS 17.240
English Version
Determination of the characteristic limits (decision
threshold, detection limit and limits of the coverage
interval) for measurements of ionizing radiation -
Fundamentals and application - Part 1: Elementary
applications (ISO 11929-1:2019)
Détermination des limites caractéristiques (seuil de Bestimmung der charakteristischen Grenzen
décision, limite de détection et extrémités de (Erkennungsgrenze, Nachweisgrenze und Grenzen des
l'intervalle élargi) pour mesurages de rayonnements Überdeckungsintervalls) bei Messungen ionisierender
ionisants - Principes fondamentaux et applications - Strahlung - Grundlagen und Anwendungen - Teil 1:
Partie 1: Applications élémentaires (ISO 11929- Elementare Anwendungen (ISO 11929-1:2019)
1:2019)
This European Standard was approved by CEN on 18 January 2021.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11929-1:2021 E
worldwide for CEN national Members.
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SIST EN ISO 11929-1:2021
EN ISO 11929-1:2021 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 11929-1:2021
EN ISO 11929-1:2021 (E)
European foreword
The text of ISO 11929-1:2019 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 11929-1:2021 by Technical Committee CEN/TC 430 “Nuclear
energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2021, and conflicting national standards shall
be withdrawn at the latest by August 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 11929-1:2019 has been approved by CEN as EN ISO 11929-1:2021 without any
modification.
3
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SIST EN ISO 11929-1:2021
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SIST EN ISO 11929-1:2021
INTERNATIONAL ISO
STANDARD 11929-1
Second edition
2019-02
Determination of the characteristic
limits (decision threshold, detection
limit and limits of the coverage
interval) for measurements of ionizing
radiation — Fundamentals and
application —
Part 1:
Elementary 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 1: Applications élémentaires
Reference number
ISO 11929-1:2019(E)
©
ISO 2019
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SIST EN ISO 11929-1:2021
ISO 11929-1:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii © ISO 2019 – All rights reserved
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SIST EN ISO 11929-1:2021
ISO 11929-1:2019(E)
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 a measurement and calculating the
characteristic limits . 8
5.1 General aspects . 8
5.2 Modelling the measurement . 9
5.3 General considerations about the applicability of the ISO/IEC Guide 98-3 . 9
5.4 Evaluating the input quantities, standard uncertainties and covariances, and the
primary result and its associated standard uncertainty .10
5.5 Evaluating the standard uncertainty as a function of an assumed true value of the
measurand .10
5.6 Calculating the decision threshold and decisions to be made .11
5.7 Calculating the detection limit and assessment of the measurement procedure .12
5.8 Calculating a coverage interval for the measurand .12
5.9 Calculating the best estimate of the measurand and its associated standard uncertainty 13
5.10 Reporting the results .14
6 Fundamentals and evaluation of the measurement .16
6.1 General aspects concerning the measurand .16
6.2 Model of evaluation .16
6.2.1 General model .16
6.2.2 Model in ionizing radiation counting measurements .17
6.3 Evaluation of the primary measurement result .18
6.4 Standard uncertainty associated with the primary measurement result .18
7 Standard uncertainty as a function of an assumed value of the measurand .19
8 Decision threshold, detection limit and assessments .21
8.1 Specifications.21
8.2 Decision threshold .21
8.3 Detection limit .21
8.4 Assessments .22
9 Limits of the coverage interval .23
9.1 General aspects .23
9.2 The probabilistically symmetric coverage interval .23
9.3 The shortest coverage interval .24
10 The best estimate and its associated standard uncertainty .24
11 Documentation .25
Annex A (normative) Repeated counting measurements with random influences .26
Annex B (normative) Measurements with ratemeters .31
Annex C (informative) Calculation of the detection limit by iteration .33
Annex D (informative) Calculations with a generalized net count rate .35
Annex E (informative) Distribution function of the standardized normal distribution .38
Bibliography .40
© ISO 2019 – All rights reserved iii
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SIST EN ISO 11929-1:2021
ISO 11929-1:2019(E)
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
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 This document was prepared by ISO/TC 85, Nuclear energy, nuclear
technologies, and radiological protection, Subcommittee SC 2, Radiological protection.
This second edition of ISO 11929-1 together with ISO 11929-2 and ISO 11929-3, cancels and replaces
ISO 11929:2010, which has been technically revised. The main change is specifically with reference
to the type of statistical treatment of the data and extended with respect to the methodology of
uncertainty assessment from ISO/IEC Guide 98-3:2009, to the ISO/IEC Guide 98-3-1:2008.
A list of all the parts in the ISO 11929 series can be found on the ISO website.
iv © ISO 2019 – All rights reserved
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SIST EN ISO 11929-1:2021
ISO 11929-1:2019(E)
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, at the end, the basis for deciding if
uncertainties have to be taken into account.
This standard 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 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 as well as on
the ISO/IEC Guide 98-3-1 and ISO/IEC 98-3-2. 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 ISO 11929, 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 98-3-1; see also References [13] to [17].
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 series makes use
of a theory of uncertainty in measurement [18] to [20] based on Bayesian statistics (e.g. see References
[21] to [26]) in order to take into account 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 ISO/IEC Guide 98-3. Moreover, ISO 11929:2010 was based on the definitions
[13] [14] [15]
of the characteristic values , the standard proposal , and the explanatory article . 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.
In 2008 the ISO/IEC Guide 98-3-1 has been published, dealing comprehensively with a more general
treatment of measurement uncertainty using the Monte Carlo method in complex measurement
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SIST EN ISO 11929-1:2021
ISO 11929-1:2019(E)
[16]
evaluations. This provided an incentive for writing a corresponding Monte Carlo supplement 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-
1. 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 revised ISO 11929, moreover, is more explicit on the calculation of the characteristic values. It
corrects also a problem in ISO 11929:2010 regarding uncertain quantities and influences, which do not
behave randomly in measurements repeated several times. Reference [17] gives a survey on the basis
of the revision. Furthermore, in ISO 11929-3, it gives detailed advice how to calculate characteristic
values in the case of multivariate measurements using unfolding methods. For such measurements, the
ISO/IEC Guide 3-2 provides the basis of the uncertainty evaluation.
Formulas are provided for the calculation of the characteristic values of an ionizing radiation measurand
via the “standard measurement uncertainty” of the measurand (hereinafter the “standard uncertainty”)
derived according to the ISO/IEC Guide 98-3 as well as via probability density functions (PDFs) of
the measurand derived in accordance with the ISO/IEC Guide 98-3-1. The standard uncertainties or
probability density functions take into account the uncertainties of the actual measurement as well
as those of sample treatment, calibration of the measuring system and other influences. The latter
uncertainties are assumed to be known from previous investigations.
vi © ISO 2019 – All rights reserved
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SIST EN ISO 11929-1:2021
INTERNATIONAL STANDARD ISO 11929-1:2019(E)
Determination of the characteristic limits (decision
threshold, detection limit and limits of the coverage
interval) for measurements of ionizing radiation —
Fundamentals and application —
Part 1:
Elementary applications
1 Scope
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 this document, advanced
applications on the basis of the ISO/IEC Guide 3-1 in ISO 11929-2, applications to unfolding methods in
ISO 11929-3, and guidance to the application in ISO 11929-4.
This document 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, the special case of repeated
counting measurements with random influences is covered, while measurements with linear analogous
ratemeters are covered in Annex B.
ISO 11929-2 extends the former ISO 11929:2010 to the evaluation of measurement uncertainties
according to the ISO/IEC Guide 98-3-1. ISO 11929-2 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 the ISO 11929 series, summarizes shortly the general
procedure and then presents a wide range of numerical examples. Information on the statistical roots
[33][34]
of ISO 11929 and on its current development may be found elsewhere .
The ISO 11929 series 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,
[1] [2] [3] [4] [5] [6] [7]
in ISO 18589 , ISO 9696 , ISO 9697 , ISO 9698 , ISO 10703 , ISO 7503 , ISO 28218 , and
[8]
ISO 11665 .
NOTE A code system, named UncertRadio, is available for calculations according to ISO 11929-1
[31][32]
to ISO 11929-3. UncertRadio can be downloaded for free from https: //www .thuenen
.de/de/fi/arbeitsbereiche/meeresumwelt/leitstelle -umweltradioaktivitaet -in -fisch/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.
© ISO 2019 – All rights reserved 1
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SIST EN ISO 11929-1:2021
ISO 11929-1:2019(E)
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 3534-1, Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in
probability
ISO 80000-1, Quantities and units — Part 1: General
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 1: Guide to the expression of uncertainty in
measurement, JCGM 100:2008.
ISO/IEC Guide 98-3-1, Evaluation of measurement data — Supplement 1 to the “Guide to the expression of
uncertainty in measurement” — a Propagation of distributions using a Monte Carlo method, JCGM 101:2008
ISO/IEC Guide 98-3-2, Evaluation of measurement data — Supplement 2 to the “Guide to the expression of
uncertainty in measurement” — Models with any number of output quantities, JCGM 102:2011
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM), JCGM 200:2012
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 80000-1, ISO 80000-10,
ISO/IEC Guide 98-3, ISO/IEC Guide 98-3-1, ISO/IEC 98-3-2, ISO/IEC Guide 99 and ISO 3534-1 and the
following apply.
3.1
quantity value
value of a quantity
value
number and reference together expressing magnitude of a quantity
[SOURCE: JCGM 200:2012, 1.19]
3.2
measurement
process of experimentally obtaining one or more quantity values that can reasonably be attributed to a
quantity
[SOURCE: JCGM 200:2012, 2.1]
3.3
measurand
quantity intended to be measured
[SOURCE: JCGM 200:2012, 2.3]
3.4
coverage interval
interval containing the set of true quantity values of a measurand with a stated probability, based on
the information available
[SOURCE: JCGM 200:2012, 2.36]
Note 1 to entry: A coverage interval does not need to be centred on the chosen measured quantity value (see
JCGM
...
SLOVENSKI STANDARD
oSIST prEN ISO 11929-1:2020
01-december-2020
Ugotavljanje karakterističnih mej (odločitveni prag, zaznavanje meje in omejitev
intervala pokritja) pri meritvah ionizirnega sevanja - Osnove in uporaba - 1. del:
Osnovne aplikacije (ISO 11929-1:2019)
Determination of the characteristic limits (decision threshold, detection limit and limits of
the coverage interval) for measurements of ionizing radiation - Fundamentals and
application - Part 1: Elementary applications (ISO 11929-1:2019)
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 1: Applications élémentaires (ISO 11929-1:2019)
Ta slovenski standard je istoveten z: prEN ISO 11929-1
ICS:
17.240 Merjenje sevanja Radiation measurements
oSIST prEN ISO 11929-1:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
oSIST prEN ISO 11929-1:2020
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oSIST prEN ISO 11929-1:2020
INTERNATIONAL ISO
STANDARD 11929-1
Second edition
2019-02
Determination of the characteristic
limits (decision threshold, detection
limit and limits of the coverage
interval) for measurements of ionizing
radiation — Fundamentals and
application —
Part 1:
Elementary 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 1: Applications élémentaires
Reference number
ISO 11929-1:2019(E)
©
ISO 2019
---------------------- Page: 3 ----------------------
oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019
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
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Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved
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oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
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 a measurement and calculating the
characteristic limits . 8
5.1 General aspects . 8
5.2 Modelling the measurement . 9
5.3 General considerations about the applicability of the ISO/IEC Guide 98-3 . 9
5.4 Evaluating the input quantities, standard uncertainties and covariances, and the
primary result and its associated standard uncertainty .10
5.5 Evaluating the standard uncertainty as a function of an assumed true value of the
measurand .10
5.6 Calculating the decision threshold and decisions to be made .11
5.7 Calculating the detection limit and assessment of the measurement procedure .12
5.8 Calculating a coverage interval for the measurand .12
5.9 Calculating the best estimate of the measurand and its associated standard uncertainty 13
5.10 Reporting the results .14
6 Fundamentals and evaluation of the measurement .16
6.1 General aspects concerning the measurand .16
6.2 Model of evaluation .16
6.2.1 General model .16
6.2.2 Model in ionizing radiation counting measurements .17
6.3 Evaluation of the primary measurement result .18
6.4 Standard uncertainty associated with the primary measurement result .18
7 Standard uncertainty as a function of an assumed value of the measurand .19
8 Decision threshold, detection limit and assessments .21
8.1 Specifications.21
8.2 Decision threshold .21
8.3 Detection limit .21
8.4 Assessments .22
9 Limits of the coverage interval .23
9.1 General aspects .23
9.2 The probabilistically symmetric coverage interval .23
9.3 The shortest coverage interval .24
10 The best estimate and its associated standard uncertainty .24
11 Documentation .25
Annex A (normative) Repeated counting measurements with random influences .26
Annex B (normative) Measurements with ratemeters .31
Annex C (informative) Calculation of the detection limit by iteration .33
Annex D (informative) Calculations with a generalized net count rate .35
Annex E (informative) Distribution function of the standardized normal distribution .38
Bibliography .40
© ISO 2019 – All rights reserved iii
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oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
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 This document was prepared by ISO/TC 85, Nuclear energy, nuclear
technologies, and radiological protection, Subcommittee SC 2, Radiological protection.
This second edition of ISO 11929-1 together with ISO 11929-2 and ISO 11929-3, cancels and replaces
ISO 11929:2010, which has been technically revised. The main change is specifically with reference
to the type of statistical treatment of the data and extended with respect to the methodology of
uncertainty assessment from ISO/IEC Guide 98-3:2009, to the ISO/IEC Guide 98-3-1:2008.
A list of all the parts in the ISO 11929 series can be found on the ISO website.
iv © ISO 2019 – All rights reserved
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oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
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, at the end, the basis for deciding if
uncertainties have to be taken into account.
This standard 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 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 as well as on
the ISO/IEC Guide 98-3-1 and ISO/IEC 98-3-2. 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 ISO 11929, 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 98-3-1; see also References [13] to [17].
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 series makes use
of a theory of uncertainty in measurement [18] to [20] based on Bayesian statistics (e.g. see References
[21] to [26]) in order to take into account 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 ISO/IEC Guide 98-3. Moreover, ISO 11929:2010 was based on the definitions
[13] [14] [15]
of the characteristic values , the standard proposal , and the explanatory article . 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.
In 2008 the ISO/IEC Guide 98-3-1 has been published, dealing comprehensively with a more general
treatment of measurement uncertainty using the Monte Carlo method in complex measurement
© ISO 2019 – All rights reserved v
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oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
[16]
evaluations. This provided an incentive for writing a corresponding Monte Carlo supplement 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-
1. 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 revised ISO 11929, moreover, is more explicit on the calculation of the characteristic values. It
corrects also a problem in ISO 11929:2010 regarding uncertain quantities and influences, which do not
behave randomly in measurements repeated several times. Reference [17] gives a survey on the basis
of the revision. Furthermore, in ISO 11929-3, it gives detailed advice how to calculate characteristic
values in the case of multivariate measurements using unfolding methods. For such measurements, the
ISO/IEC Guide 3-2 provides the basis of the uncertainty evaluation.
Formulas are provided for the calculation of the characteristic values of an ionizing radiation measurand
via the “standard measurement uncertainty” of the measurand (hereinafter the “standard uncertainty”)
derived according to the ISO/IEC Guide 98-3 as well as via probability density functions (PDFs) of
the measurand derived in accordance with the ISO/IEC Guide 98-3-1. The standard uncertainties or
probability density functions take into account the uncertainties of the actual measurement as well
as those of sample treatment, calibration of the measuring system and other influences. The latter
uncertainties are assumed to be known from previous investigations.
vi © ISO 2019 – All rights reserved
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oSIST prEN ISO 11929-1:2020
INTERNATIONAL STANDARD ISO 11929-1:2019(E)
Determination of the characteristic limits (decision
threshold, detection limit and limits of the coverage
interval) for measurements of ionizing radiation —
Fundamentals and application —
Part 1:
Elementary applications
1 Scope
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 this document, advanced
applications on the basis of the ISO/IEC Guide 3-1 in ISO 11929-2, applications to unfolding methods in
ISO 11929-3, and guidance to the application in ISO 11929-4.
This document 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, the special case of repeated
counting measurements with random influences is covered, while measurements with linear analogous
ratemeters are covered in Annex B.
ISO 11929-2 extends the former ISO 11929:2010 to the evaluation of measurement uncertainties
according to the ISO/IEC Guide 98-3-1. ISO 11929-2 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 the ISO 11929 series, summarizes shortly the general
procedure and then presents a wide range of numerical examples. Information on the statistical roots
[33][34]
of ISO 11929 and on its current development may be found elsewhere .
The ISO 11929 series 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,
[1] [2] [3] [4] [5] [6] [7]
in ISO 18589 , ISO 9696 , ISO 9697 , ISO 9698 , ISO 10703 , ISO 7503 , ISO 28218 , and
[8]
ISO 11665 .
NOTE A code system, named UncertRadio, is available for calculations according to ISO 11929-1
[31][32]
to ISO 11929-3. UncertRadio can be downloaded for free from https: //www .thuenen
.de/de/fi/arbeitsbereiche/meeresumwelt/leitstelle -umweltradioaktivitaet -in -fisch/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.
© ISO 2019 – All rights reserved 1
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oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
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 3534-1, Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in
probability
ISO 80000-1, Quantities and units — Part 1: General
ISO 80000-10, Quantities and units — Part 10: Atomic and nuclear physics
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 1: Guide to the expression of uncertainty in
measurement, JCGM 100:2008.
ISO/IEC Guide 98-3-1, Evaluation of measurement data — Supplement 1 to the “Guide to the expression of
uncertainty in measurement” — a Propagation of distributions using a Monte Carlo method, JCGM 101:2008
ISO/IEC Guide 98-3-2, Evaluation of measurement data — Supplement 2 to the “Guide to the expression of
uncertainty in measurement” — Models with any number of output quantities, JCGM 102:2011
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM), JCGM 200:2012
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 80000-1, ISO 80000-10,
ISO/IEC Guide 98-3, ISO/IEC Guide 98-3-1, ISO/IEC 98-3-2, ISO/IEC Guide 99 and ISO 3534-1 and the
following apply.
3.1
quantity value
value of a quantity
value
number and reference together expressing magnitude of a quantity
[SOURCE: JCGM 200:2012, 1.19]
3.2
measurement
process of experimentally obtaining one or more quantity values that can reasonably be attributed to a
quantity
[SOURCE: JCGM 200:2012, 2.1]
3.3
measurand
quantity intended to be measured
[SOURCE: JCGM 200:2012, 2.3]
3.4
coverage interval
interval containing the set of true quantity values of a measurand with a stated probability, based on
the information available
[SOURCE: JCGM 200:2012, 2.36]
Note 1 to entry: A coverage interval does not need to be centred on the chosen measured quantity value (see
JCGM 101:2008).
2 © ISO 2019 – All rights reserved
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oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
Note 2 to entry: A coverage interval should not be termed “confidence interval” to avoid confusion with the
statistical concept.
3.5
measurement method
method of measurement
generic description of a logical organization of operations used in a measurement
[SOURCE: JCGM 200:2012, 2.4]
3.6
measurement procedure
detailed description of a measurement according to one or more measurement principles and to a
given measurement method, based on a measurement model and including any calculation to obtain a
measurement result
[SOURCE: JCGM 200:2012, 2.6]
3.7
measurement result
result of measurement
set of quantity values being attributed to a measurand together with any other available relevant
information
[SOURCE: JCGM 200:2012, 2.9]
3.8
measured quantity value
value of a measured quantity
measured value
quantity value representing a measurement result
[SOURCE: JCGM 200:2012, 2.10]
3.9
true quantity value
true value of a quantity
true value
quantity value consistent with the definition of a quantity
[SOURCE: JCGM 200:2012, 2.11]
Note 1 to entry: In the Error Approach to describing measurement, a true quantity value is considered unique
and, in practice, unknowable. The Uncertainty Approach is to recognize that, owing to the inherently incomplete
amount of detail in the definition of a quantity, there is not a single true quantity value but rather a set of
true quantity values consistent with the definition. However, this set of values is, in principle and in practice,
unknowable. Other approaches dispense altogether with the concept of true quantity value and rely on the
concept of metrological compatibility of measurement results for assessing their validity.
Note 2 to entry: When the definitional uncertainty associated with the measurand is considered to be negligible
compared to the other components of the measurement uncertainty, the measurand may be considered to have
an “essentially unique” true quantity value. This is the approach taken by the ISO/IEC Guide 98-3 and associated
documents, where the word “true” is considered to be redundant.
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oSIST prEN ISO 11929-1:2020
ISO 11929-1:2019(E)
3.10
measurement uncertainty
uncertainty of measurement
uncertainty
non-negative parameter characterizing the dispersion of the quantity values being attributed to a
measurand, based on the information used
[SOURCE: JCGM 200:2012, 2.26]
Note 1 to entry: Measurement uncertainty includes components arising from systematic effects, such as
components associated with corrections and the assigned quantity values of measurement standards, as well
as the definitional uncertainty. Sometimes estimated systematic effects are not corrected for but, instead,
associated measurement uncertainty components are incorporated.
Note 2 to entry: The parameter may be, for example, a standard deviation called standard measurement
uncertainty (or a specified multiple of it), or the half-width of an interval, having a stated coverage probability.
Note 3 to entry: Measurement uncertainty comprises, in general, many components. Some of these may be
evaluated by Type A evaluation of measurement uncertainty from the statistical distribution of the quantity
values from series of measurements and can be characterized by standard deviations. The other components,
which may be evaluated by Type B evaluation of measurement uncertainty, can also be characterized by standard
deviations, evaluated from probability density functions based on experience or other information.
Note 4 to entry: In general, for a given set of information, it is understood that the measurement uncertainty is
associated with a stated quantity value attributed to the measurand. A modification of this value results in a
modification of the associated uncertainty.
3.11
model of evaluation
set of mathematical relationships between all measured and other quantities involved in the evaluation
of measurements
Note 1 to entry: The model of evaluation does not need to be an explicit function; it can also be an algorithm
realized by a computer code.
3.12
decision threshold
value of the estimator of the measurand, which, when exceeded by the result of an actual measurement
using a given measurement procedure of a measurand quantifying a physical effect, is used to decide
that the physical effect is present
Note 1 to entry: The decision threshold is defined such that in cases where the measur
...
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