NF ISO 21748
Guidance for the use of repeatability, reproducibility and trueness estimates in measurement uncertainty estimation
ISO 21748:2010 gives guidance for evaluation of measurement uncertainties using data obtained from studies conducted in accordance with ISO 5725-2:1994; comparison of collaborative study results with measurement uncertainty (MU) obtained using formal principles of uncertainty propagation. (ISO 5725-3:1994 provides additional models for studies of intermediate precision. However, while the same general approach may be applied to the use of such extended models, uncertainty evaluation using these models is not incorporated in ISO 21748:2010.)ISO 21748:2010 is applicable in all measurement and test fields where an uncertainty associated with a result has to be determined. It does not describe the application of repeatability data in the absence of reproducibility data.ISO 21748:2010 assumes that recognized, non-negligible systematic effects are corrected, either by applying a numerical correction as part of the method of measurement, or by investigation and removal of the cause of the effect.The recommendations in ISO 21748:2010 are primarily for guidance. It is recognized that while the recommendations presented do form a valid approach to the evaluation of uncertainty for many purposes, it is also possible to adopt other suitable approaches. In general, references to measurement results, methods and processes in ISO 21748:2010 are normally understood to apply also to testing results, methods and processes.
ISO 21748:2010 gives guidance for evaluation of measurement uncertainties using data obtained from studies conducted in accordance with ISO 5725-2:1994; comparison of collaborative study results with measurement uncertainty (MU) obtained using formal principles of uncertainty propagation. (ISO 5725-3:1994 provides additional models for studies of intermediate precision. However, while the same general approach may be applied to the use of such extended models, uncertainty evaluation using these models is not incorporated in ISO 21748:2010.)
ISO 21748:2010 is applicable in all measurement and test fields where an uncertainty associated with a result has to be determined. It does not describe the application of repeatability data in the absence of reproducibility data.
ISO 21748:2010 assumes that recognized, non-negligible systematic effects are corrected, either by applying a numerical correction as part of the method of measurement, or by investigation and removal of the cause of the effect.
The recommendations in ISO 21748:2010 are primarily for guidance. It is recognized that while the recommendations presented do form a valid approach to the evaluation of uncertainty for many purposes, it is also possible to adopt other suitable approaches. In general, references to measurement results, methods and processes in ISO 21748:2010 are normally understood to apply also to testing results, methods and processes.
TS 21748:2004 gives guidance for the evaluation of measurement uncertainties using data obtained from studies conducted in accordance with ISO 5725-2, and for the comparison of collaborative study results with measurement uncertainty obtained using formal principles of uncertainty propagation. TS 21748:2003 is applicable in all measurement and test fields where an uncertainty associated with a result has to be determined, but does not describe the application of repeatability data in the absence of reproducibility data. The recommendations in this document are primarily for guidance.
ISO 21748:2017 gives guidance for - evaluation of measurement uncertainties using data obtained from studies conducted in accordance with ISO 5725‑2, and - comparison of collaborative study results with measurement uncertainty (MU) obtained using formal principles of uncertainty propagation (see Clause 14). ISO 5725‑3 provides additional models for studies of intermediate precision. However, while the same general approach may be applied to the use of such extended models, uncertainty evaluation using these models is not incorporated in this document. ISO 21748:2017 is applicable to all measurement and test fields where an uncertainty associated with a result has to be determined. ISO 21748:2017 does not describe the application of repeatability data in the absence of reproducibility data. ISO 21748:2017 assumes that recognized, non-negligible systematic effects are corrected, either by applying a numerical correction as part of the method of measurement, or by investigation and removal of the cause of the effect. The recommendations in this document are primarily for guidance. It is recognized that while the recommendations presented do form a valid approach to the evaluation of uncertainty for many purposes, it is also possible to adopt other suitable approaches. In general, references to measurement results, methods and processes in this document are normally understood to apply also to testing results, methods and processes.
- Avant-proposiv
- Introductionv
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1 Domaine d'application1
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2 Termes et définitions1
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3 Symboles5
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4 Principes7
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4.1 Résultats individuels et performance du processus de mesure7
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4.2 Utilisation des données de reproductibilité8
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4.3 Équations fondamentales pour le modèle statistique8
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4.4 Données de répétabilité9
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5 Évaluation de l'incertitude de mesure à l'aide des estimations de la répétabilité, de la reproductibilité et de la justesse9
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5.1 Mode opératoire pour l'évaluation de l'incertitude de mesure9
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5.2 Différences entre fidélité attendue et fidélité réelle10
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6 Établissement de la pertinence des données de performance de la méthode aux résultats de mesure à partir d'un processus de mesure particulier10
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6.1 Généralités10
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6.2 Démonstration du contrôle de la composante du biais imputable au laboratoire10
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6.3 Vérification de la répétabilité13
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6.4 Vérification continue de la performance13
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7 Établissement de la pertinence de l'individu d'essai14
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7.1 Généralités14
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7.2 Échantillonnage14
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7.3 Préparation et traitement préalable des échantillons14
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7.4 Changements du type d'individu d'essai14
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7.5 Variation de l'incertitude avec le niveau de réponse15
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8 Facteurs supplémentaires15
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9 Expression générale pour l'estimation de l'incertitude-type composée16
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10 Budgets d'incertitude fondés sur des données d'essais interlaboratoires16
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11 Évaluation de l'incertitude pour un résultat composé18
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12 Expression de l'information sur l'incertitude18
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12.1 Expression générale18
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12.2 Choix du facteur d'élargissement18
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13 Comparaison des valeurs de performance d'une méthode et des données d'incertitude19
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13.1 Hypothèses de base pour la comparaison19
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13.2 Mode opératoire de comparaison20
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13.3 Raisons des différences20
- Annexe A (informative) Méthodes d'estimation de l'incertitude21
- Annexe B (informative) Évaluation expérimentale de l'incertitude26
- Annexe C (informative) Exemples de calcul de l'incertitude de mesure27
- Bibliographie38
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