.png)
ISO 13528 : 2022 Statistical methods for use in proficiency testing by interlaboratory comparison (Full)
.png)
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 on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 69, Applications of statistical methods, Subcommittee SC 6, Measurement methods and results.
This third edition of ISO 13528 cancels and replaces the second edition (ISO 13528:2015), of which it constitutes an minor revision. The changes are as follows:
— notes have been added to 10.1, 10.4.3 and 10.5.3 to draw attention to additional graphical techniques that can assist in meeting the provisions of 10.1;
— Formulae B.4 and B.8 have been corrected to use mml_m1 instead of mml_m2;
— Formula B.16 has been corrected so that the term inside the square root is always non-negative;
— in Table C.2, the correction factor associated with p = 2 has been corrected to read 0,3994;
— additional literature references to the source of values in Table C.2 have been added to the Bibliography and referenced from Notes 1 and 2 of C.5.2.1;
— font styles (Italic or Roman) have been amended throughout for consistency in formulae.
0 Introduction
0.1 The purposes of proficiency testing
Proficiency testing involves the use of interlaboratory comparisons to determine the performance of participants (which may be laboratories, inspection bodies, or individuals) for specific tests or measurements, and to monitor their continuing performance. There are a number of typical purposes of proficiency testing, as described in the Introduction to ISO/IEC 17043. These include the evaluation of laboratory performance, the identification of problems in laboratories, establishing effectiveness and comparability of test or measurement methods, the provision of additional confidence to laboratory customers, validation of uncertainty claims, and the education of participating laboratories. The statistical design and analytical techniques applied shall be appropriate for the stated purpose(s).
0.2 Rationale for scoring in proficiency testing schemes
A variety of scoring strategies is available and in use for proficiency testing. Although the detailed calculations differ, most proficiency testing schemes compare the participant’s deviation from an assigned value with a numerical criterion which is used to decide whether or not the deviation represents cause for concern. The strategies used for value assignment and for choosing a criterion for assessment of the participant deviations are therefore critical. In particular, it is important to consider whether the assigned value and criterion for assessing deviations should be independent of participant results, or should be derived from the results submitted. In this document, both strategies are provided for. However, attention is drawn to the discussion that will be found in Clauses 7 and 8 of the advantages and disadvantages of choosing assigned values or criteria for assessing deviations that are not derived from the participant results. It will be seen that in general, choosing assigned values and assessment criteria independently of participant results offers advantages.
NỘI DUNG:
Foreword ..........................................................................................................................................................................................................................................v
0
Introduction ............................................................................................................................................................................................................vi
1 Scope .................................................................................................................................................................................................................................1
2 Normative references .....................................................................................................................................................................................1
3 Terms and definitions ....................................................................................................................................................................................1
4 General principles ..............................................................................................................................................................................................4
4.1 General requirements for statistical methods ...........................................................................................................4
4.2 Basic model ................................................................................................................................................................................................5
4.3 General approaches for the evaluation of performance ....................................................................................5
5 Guidelines for the statistical design of proficiency testing schemes ...........................................................6
5.1 Introduction to the statistical design of proficiency testing schemes ..................................................6
5.2 Basis of a statistical design .........................................................................................................................................................6
5.3 Considerations for the statistical distribution of results .................................................................................7
5.4 Considerations for small numbers of participants .................................................................................................8
5.5 Guidelines for choosing the reporting format ............................................................................................................8
5.5.1 General requirements for reporting format ..............................................................................................8
5.5.2 Reporting of replicate measurements .............................................................................................................9
5.5.3 Reporting of ‘less than’ or ‘greater than’ a limit (censored data) ...........................................9
5.5.4 Number of significant digits .....................................................................................................................................9
6 Guidelines for the initial review of proficiency testing items and results..........................................10
6.1 Homogeneity and stability of proficiency test items .........................................................................................10
6.2 Considerations for different measurement methods ........................................................................................11
6.3 Blunder removal .................................................................................................................................................................................11
6.4 Visual review of data ......................................................................................................................................................................12
6.5 Robust statistical methods .......................................................................................................................................................12
6.6 Outlier techniques for individual results .....................................................................................................................13
7 Determination of the assigned value and its standard uncertainty .........................................................14
7.1 Choice of method of determining the assigned value .......................................................................................14
7.2 Determining the uncertainty of the assigned value ...........................................................................................14
7.3 Formulation ............................................................................................................................................................................................15
7.4 Certified reference material ....................................................................................................................................................16
7.5 Results from one laboratory ...................................................................................................................................................16
7.6 Consensus value from expert laboratories ................................................................................................................17
7.7 Consensus value from participant results ..................................................................................................................18
7.8 Comparison of the assigned value with an independent reference value ......................................19
8 Determination of criteria for evaluation of performance ....................................................................................20
8.1 Approaches for determining evaluation criteria ..................................................................................................20
8.2 By perception of experts.............................................................................................................................................................21
8.3 By experience from previous rounds of a proficiency testing scheme ..............................................21
8.4 By use of a general model ...........................................................................................................................................................21
8.5 Using the repeatability and reproducibility standard deviations from a previous
collaborative study of precision of a measurement method ......................................................................22
8.6 From data obtained in the same round of a proficiency testing scheme .........................................22
8.7 Monitoring interlaboratory agreement .........................................................................................................................23
9 Calculation of performance statistics ........................................................................................................................................24
9.1 General considerations for determining performance ....................................................................................24
9.2 Limiting the uncertainty of the assigned value .....................................................................................................24
9.3 Estimates of deviation (measurement error) ...........................................................................................................25
9.4 zscores .......................................................................................................................................................................................................26
9.5 z′scores ......................................................................................................................................................................................................27
iii © ISO 2022 – All rights reserved
Contents Page
Licensed to (lyphan@aov.vn)
ISO Store Order: OP-629806 / Downloaded: 2022-09-13
Single user licence only, copying and networking prohibited.
ISO 13528:2022(E)
9.6 Zeta scores (ζ) ......................................................................................................................................................................................28
9.7 En
scores ....................................................................................................................................................................................................29
9.8 Evaluation of participant uncertainties in testing ..............................................................................................30
9.9 Combined performance scores .............................................................................................................................................31
10 Graphical methods for describing performance scores .........................................................................................32
10.1 Application of graphical methods .......................................................................................................................................32
10.2 Histograms of results or performance scores .........................................................................................................32
10.3 Kernel density plots ........................................................................................................................................................................33
10.4 Bar-plots of standardized performance scores ......................................................................................................34
10.5 Youden plot..............................................................................................................................................................................................34
10.6 Plots of repeatability standard deviations .................................................................................................................35
10.7 Split samples ..........................................................................................................................................................................................36
10.8 Graphical methods for combining performance scores over several rounds of a
proficiency testing scheme .......................................................................................................................................................37
11 Design and analysis of qualitative proficiency testing schemes (including nominal
and ordinal properties) .............................................................................................................................................................................38
11.1 Types of qualitative data ............................................................................................................................................................38
11.2 Statistical design................................................................................................................................................................................38
11.3 Assigned values for qualitative proficiency testing schemes ....................................................................39
11.4 Performance evaluation and scoring for qualitative proficiency testing schemes ................40
Annex A (normative)Symbols .................................................................................................................................................................................42
Annex B (informative)Homogeneity and stability of proficiency test items .......................................................44
Annex C (informative)Robust analysis ..........................................................................................................................................................52
Annex D (informative)Additional guidance on statistical procedures ......................................................................63
Annex E (informative)Illustrative examples ........68
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 on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 69, Applications of statistical methods, Subcommittee SC 6, Measurement methods and results.
This third edition of ISO 13528 cancels and replaces the second edition (ISO 13528:2015), of which it constitutes an minor revision. The changes are as follows:
— notes have been added to 10.1, 10.4.3 and 10.5.3 to draw attention to additional graphical techniques that can assist in meeting the provisions of 10.1;
— Formulae B.4 and B.8 have been corrected to use mml_m1 instead of mml_m2;
— Formula B.16 has been corrected so that the term inside the square root is always non-negative;
— in Table C.2, the correction factor associated with p = 2 has been corrected to read 0,3994;
— additional literature references to the source of values in Table C.2 have been added to the Bibliography and referenced from Notes 1 and 2 of C.5.2.1;
— font styles (Italic or Roman) have been amended throughout for consistency in formulae.
0 Introduction
0.1 The purposes of proficiency testing
Proficiency testing involves the use of interlaboratory comparisons to determine the performance of participants (which may be laboratories, inspection bodies, or individuals) for specific tests or measurements, and to monitor their continuing performance. There are a number of typical purposes of proficiency testing, as described in the Introduction to ISO/IEC 17043. These include the evaluation of laboratory performance, the identification of problems in laboratories, establishing effectiveness and comparability of test or measurement methods, the provision of additional confidence to laboratory customers, validation of uncertainty claims, and the education of participating laboratories. The statistical design and analytical techniques applied shall be appropriate for the stated purpose(s).
0.2 Rationale for scoring in proficiency testing schemes
A variety of scoring strategies is available and in use for proficiency testing. Although the detailed calculations differ, most proficiency testing schemes compare the participant’s deviation from an assigned value with a numerical criterion which is used to decide whether or not the deviation represents cause for concern. The strategies used for value assignment and for choosing a criterion for assessment of the participant deviations are therefore critical. In particular, it is important to consider whether the assigned value and criterion for assessing deviations should be independent of participant results, or should be derived from the results submitted. In this document, both strategies are provided for. However, attention is drawn to the discussion that will be found in Clauses 7 and 8 of the advantages and disadvantages of choosing assigned values or criteria for assessing deviations that are not derived from the participant results. It will be seen that in general, choosing assigned values and assessment criteria independently of participant results offers advantages.
NỘI DUNG:
Foreword ..........................................................................................................................................................................................................................................v
0
Introduction ............................................................................................................................................................................................................vi
1 Scope .................................................................................................................................................................................................................................1
2 Normative references .....................................................................................................................................................................................1
3 Terms and definitions ....................................................................................................................................................................................1
4 General principles ..............................................................................................................................................................................................4
4.1 General requirements for statistical methods ...........................................................................................................4
4.2 Basic model ................................................................................................................................................................................................5
4.3 General approaches for the evaluation of performance ....................................................................................5
5 Guidelines for the statistical design of proficiency testing schemes ...........................................................6
5.1 Introduction to the statistical design of proficiency testing schemes ..................................................6
5.2 Basis of a statistical design .........................................................................................................................................................6
5.3 Considerations for the statistical distribution of results .................................................................................7
5.4 Considerations for small numbers of participants .................................................................................................8
5.5 Guidelines for choosing the reporting format ............................................................................................................8
5.5.1 General requirements for reporting format ..............................................................................................8
5.5.2 Reporting of replicate measurements .............................................................................................................9
5.5.3 Reporting of ‘less than’ or ‘greater than’ a limit (censored data) ...........................................9
5.5.4 Number of significant digits .....................................................................................................................................9
6 Guidelines for the initial review of proficiency testing items and results..........................................10
6.1 Homogeneity and stability of proficiency test items .........................................................................................10
6.2 Considerations for different measurement methods ........................................................................................11
6.3 Blunder removal .................................................................................................................................................................................11
6.4 Visual review of data ......................................................................................................................................................................12
6.5 Robust statistical methods .......................................................................................................................................................12
6.6 Outlier techniques for individual results .....................................................................................................................13
7 Determination of the assigned value and its standard uncertainty .........................................................14
7.1 Choice of method of determining the assigned value .......................................................................................14
7.2 Determining the uncertainty of the assigned value ...........................................................................................14
7.3 Formulation ............................................................................................................................................................................................15
7.4 Certified reference material ....................................................................................................................................................16
7.5 Results from one laboratory ...................................................................................................................................................16
7.6 Consensus value from expert laboratories ................................................................................................................17
7.7 Consensus value from participant results ..................................................................................................................18
7.8 Comparison of the assigned value with an independent reference value ......................................19
8 Determination of criteria for evaluation of performance ....................................................................................20
8.1 Approaches for determining evaluation criteria ..................................................................................................20
8.2 By perception of experts.............................................................................................................................................................21
8.3 By experience from previous rounds of a proficiency testing scheme ..............................................21
8.4 By use of a general model ...........................................................................................................................................................21
8.5 Using the repeatability and reproducibility standard deviations from a previous
collaborative study of precision of a measurement method ......................................................................22
8.6 From data obtained in the same round of a proficiency testing scheme .........................................22
8.7 Monitoring interlaboratory agreement .........................................................................................................................23
9 Calculation of performance statistics ........................................................................................................................................24
9.1 General considerations for determining performance ....................................................................................24
9.2 Limiting the uncertainty of the assigned value .....................................................................................................24
9.3 Estimates of deviation (measurement error) ...........................................................................................................25
9.4 zscores .......................................................................................................................................................................................................26
9.5 z′scores ......................................................................................................................................................................................................27
iii © ISO 2022 – All rights reserved
Contents Page
Licensed to (lyphan@aov.vn)
ISO Store Order: OP-629806 / Downloaded: 2022-09-13
Single user licence only, copying and networking prohibited.
ISO 13528:2022(E)
9.6 Zeta scores (ζ) ......................................................................................................................................................................................28
9.7 En
scores ....................................................................................................................................................................................................29
9.8 Evaluation of participant uncertainties in testing ..............................................................................................30
9.9 Combined performance scores .............................................................................................................................................31
10 Graphical methods for describing performance scores .........................................................................................32
10.1 Application of graphical methods .......................................................................................................................................32
10.2 Histograms of results or performance scores .........................................................................................................32
10.3 Kernel density plots ........................................................................................................................................................................33
10.4 Bar-plots of standardized performance scores ......................................................................................................34
10.5 Youden plot..............................................................................................................................................................................................34
10.6 Plots of repeatability standard deviations .................................................................................................................35
10.7 Split samples ..........................................................................................................................................................................................36
10.8 Graphical methods for combining performance scores over several rounds of a
proficiency testing scheme .......................................................................................................................................................37
11 Design and analysis of qualitative proficiency testing schemes (including nominal
and ordinal properties) .............................................................................................................................................................................38
11.1 Types of qualitative data ............................................................................................................................................................38
11.2 Statistical design................................................................................................................................................................................38
11.3 Assigned values for qualitative proficiency testing schemes ....................................................................39
11.4 Performance evaluation and scoring for qualitative proficiency testing schemes ................40
Annex A (normative)Symbols .................................................................................................................................................................................42
Annex B (informative)Homogeneity and stability of proficiency test items .......................................................44
Annex C (informative)Robust analysis ..........................................................................................................................................................52
Annex D (informative)Additional guidance on statistical procedures ......................................................................63
Annex E (informative)Illustrative examples ........68
%20(1).png "Hướng dẫn download ti liệu")
.png "Hướng dẫn download ti liệu")
%20(1).png "Gói VIP Member EBOOKBKMT - Hỗ trợ tài liệu nhanh nhất, ưu tiên cho thành viên VIP (Update 2025)")
Không có nhận xét nào: