ASTM D7372-21

Standard Guide for Analysis and Interpretation of Proficiency Test Program Results

SIGNIFICANCE AND USE
5.1 This guide can be used to evaluate the performance of a laboratory or group of laboratories participating in a proficiency test (PT) program involving petroleum and petroleum products.  
5.2 Data accrued, using the techniques included in this guide, provide the ability to monitor analytical measurement system precision and bias. These data are useful for updating standard test methods, as well as for indicating areas of potential measurement system improvement for action by the laboratory. This guide serves both the individual participating laboratory and the responsible standards development group as follows:  
5.2.1 Tools and Approaches for Participating Laboratories.
Administrative Reviews
Flagged Data and Investigations
Data Normality Checks
QQ Plots
Histograms
Bias (Deviation from Mean)
Run-Sum
Z-Scores, Z′-Scores Trends
Precision Performance—TPIIND, F-test
Comparison of PTP and Individual Laboratory Site Precision  
5.2.2 Tools and Approaches for Responsible Standards Development Groups.
TPI and precision trends
Bias and precision comparisons via box & whisker plots
Normality evaluations
Relative standard deviations
Uncontrolled variables  
5.3 Reference is made in this guide to the ASTM International Proficiency Test Program on Petroleum Products, Liquid Fuels, and Lubricants, version PTP 2.0 implemented in 2016–2017. Program reports containing similarly displayed results and statistical treatments may be available in other PT programs. Appendix X2 summarizes the statistical tools referenced in this guide and Appendix X3 is a collection of examples covering QQ plots, histograms, and Run-Sum described in this guide.
SCOPE
1.1 This guide covers the evaluation and interpretation of proficiency test program (PTP) results. For proficiency test program participants, this guide describes procedures for assessing participants’ results relative to the collective PT program results and potentially improving the laboratory’s testing performance based on the assessment of findings and insights. For the committees responsible for the test methods included in PT programs, this guide describes procedures for assessing industry’s ability to perform test methods and for potentially identifying opportunities for improvements.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2021
• ICS: 11.100.01 - Laboratory medicine in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.94 - Coordinating Subcommittee on Quality Assurance and Statistics

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D7372 −21 An American National Standard
Standard Guide for
Analysis and Interpretation of Proficiency Test Program
1
Results
This standard is issued under the fixed designation D7372; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* D6617 Practice for Laboratory Bias Detection Using Single
Test Result from Standard Material
1.1 This guide covers the evaluation and interpretation of
D6792 Practice for Quality Management Systems in Petro-
proficiency test program (PTP) results. For proficiency test
leum Products, Liquid Fuels, and Lubricants Testing
program participants, this guide describes procedures for
Laboratories
assessing participants’ results relative to the collective PT
D7915 Practice for Application of Generalized Extreme
program results and potentially improving the laboratory’s
Studentized Deviate (GESD) Technique to Simultane-
testing performance based on the assessment of findings and
ously Identify Multiple Outliers in a Data Set
insights. For the committees responsible for the test methods
E177 Practice for Use of the Terms Precision and Bias in
included in PT programs, this guide describes procedures for
ASTM Test Methods
assessing industry’s ability to perform test methods and for
E456 Terminology Relating to Quality and Statistics
potentially identifying opportunities for improvements.
E2586 Practice for Calculating and Using Basic Statistics
1.2 This standard does not purport to address all of the
E2655 Guide for Reporting Uncertainty of Test Results and
safety concerns, if any, associated with its use. It is the
Use of the Term Measurement Uncertainty inASTM Test
responsibility of the user of this standard to establish appro-
Methods
priate safety, health, and environmental practices and deter-
2.2 ASTM standards used only in Appendix X3 are also
mine the applicability of regulatory limitations prior to use.
listed in X3.1.
1.3 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3. Terminology
ization established in the Decision on Principles for the
3.1 Definitions:
Development of International Standards, Guides and Recom-
3.1.1 More extensive lists of terms related to quality,
mendations issued by the World Trade Organization Technical
statistics, and related terms are found in Terminology D4175.
Barriers to Trade (TBT) Committee.
3.1.1.1 Intheeventofdisagreementbetweenthequotedtext
and the latest in the referenced standard, the latter supersedes
2. Referenced Documents
the text in this standard.
2
2.1 ASTM Standards:
3.1.2 accuracy, n—closeness of agreement between an ob-
D4175 Terminology Relating to Petroleum Products, Liquid
served value and an accepted reference value. E177, E456
Fuels, and Lubricants
3.1.2.1 Discussion—The term accuracy, when applied to a
D6259 Practice for Determination of a Pooled Limit of
set of test results, involves a combination of a random
Quantitation for a Test Method
component and of a common systematic error or bias
D6299 Practice for Applying Statistical Quality Assurance
component. E177
and Control Charting Techniques to Evaluate Analytical
3.1.3 analytical measurement system, n—a collection of one
Measurement System Performance
or more components or subsystems, such as sample handling
and preparation, test equipment, instrumentation, display
devices, data handlers, printouts or output transmitters, that are
1
This guide is under the jurisdiction of ASTM Committee D02 on Petroleum
Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcom- usedtodetermineaquantitativevalueofaspecificpropertyfor
mittee D02.94 on Coordinating Subcommittee on Quality Assurance and Statistics.
an unknown sample in accordance with a standard test method.
Current edition approved May 1, 2021. Published September 2021. Originally
3.1.4 Anderson-Darling Resolution Sensitive Statistic,
approved in 2007. Last previous edition approved in 2017 as D7372 – 17. DOI:
10.1520/D7372-21.
ADrs, n—a goodness-of-fit statistical tool used to objectively
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
test for normality of proficiency testing data.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.1.4.1 Discussion—ADrs is a modified version of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Anderson-Darling Statistic (see D6299
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D7372 − 17 D7372 − 21 An American National Standard
Standard Guide for
Analysis and Interpretation of Proficiency Test Program
1
Results
This standard is issued under the fixed designation D7372; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This guide covers the evaluation and interpretation of proficiency test program (PTP) results. For proficiency test program
participants, this guide describes procedures for assessing participants’ results relative to the collective PT program results and
potentially improving the laboratory’s testing performance based on the assessment of findings and insights. For the committees
responsible for the test methods included in PT programs, this guide describes procedures for assessing industry’s ability to
perform test methods and for potentially identifying opportunities for improvements.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D6259 Practice for Determination of a Pooled Limit of Quantitation for a Test Method
D6299 Practice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-
ment System Performance
D6617 Practice for Laboratory Bias Detection Using Single Test Result from Standard Material
D6792 Practice for Quality Management Systems in Petroleum Products, Liquid Fuels, and Lubricants Testing Laboratories
D7915 Practice for Application of Generalized Extreme Studentized Deviate (GESD) Technique to Simultaneously Identify
Multiple Outliers in a Data Set
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E2586 Practice for Calculating and Using Basic Statistics
E2655 Guide for Reporting Uncertainty of Test Results and Use of the Term Measurement Uncertainty in ASTM Test Methods
2.2 ASTM standards used only in Appendix X3 are also listed in X3.1.
1
This guide is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.94 on Coordinating Subcommittee on Quality Assurance and Statistics.
Current edition approved Oct. 1, 2017May 1, 2021. Published October 2017September 2021. Originally approved in 2007. Last previous edition approved in 20122017
as D7372 – 12.D7372 – 17. DOI: 10.1520/D7372-17.10.1520/D7372-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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D7372 − 21
3. Terminology
3.1 Definitions:
3.1.1 More extensive lists of terms related to quality, statistics, and related terms are found in Terminology D4175.
3.1.1.1 In the event of disagreement between the quoted text and the latest in the referenced standard, the latter supersedes the text
in this standard.
3.1.2 accuracy, n—closeness of agreement between an observed value and an accepted reference value. E177, E456
3.1.2.1 Discussion—
The term accuracy, when applied to a set of test results, involves a combination of a random component and of a common
systematic error or bias component. E177
3.1.3 analytical measurement system, n—a collection of one or more components or subsystems, such as sample handling and
preparation, test equipment, instrumentation, displa
...