ASTM E2489-16

Standard Practice for Statistical Analysis of One-Sample and Two-Sample Interlaboratory Proficiency Testing Programs

ABSTRACT
This practice describes methods for the statistical analysis of laboratory results obtained from interlaboratory proficiency testing programs. As in accordance with Practice E1301, proficiency testing is the use of inter-laboratory comparisons for the determination of laboratory testing or measurement performance. The methods provide direction for assessing and categorizing the performance of individual laboratories based on the relative likelihood of occurrence of their test results, and for determining estimates of testing variation associated with repeatability and reproducibility. Assumptions are that a majority of the participating laboratories execute the test method properly and that samples are of sufficient homogeneity that the testing results represent results obtained from each laboratory testing essentially the same material. Each laboratory receives the same instructions or protocol.
This practice is specifically designed to describe simple robust statistical methods for use in proficiency testing programs.
SIGNIFICANCE AND USE
5.1 This practice is specifically designed to describe simple robust statistical methods for use in proficiency testing programs.  
5.2 Proficiency testing programs can use the methods in this practice for the purpose of comparing testing results obtained from a group of participating laboratories. The laboratory comparisons can then be used for evaluation of individual laboratory performance.  
5.3 In addition, the data obtained in proficiency testing programs may contain information regarding repeatability (within-lab) and reproducibility (between-lab) testing variation. Repeatability information is possible only if the program uses more than one sample. See Method B. Proficiency testing programs often have a greater number of participants than might be available for conducting an interlaboratory study to determine the precision of a test method (such as described in Practice E691). Precision estimates obtained for the larger number of participants in a proficiency testing program, along with the corresponding wider variation of test conditions, can provide useful information to standards developers regarding the precision of test results that can be expected for a test method when in actual use in the general testing community.  
5.4 To estimate the precision of a test method, the participants must use the same test method to obtain their test results, and testing must be performed under the conditions required for repeatability and reproducibility. The precision estimates are applicable to the property levels and material types included in the testing program. The precision of a test method may vary considerably for different material types and at different property levels.  
5.5 This practice may be useful to proficiency testing program administrators and provides examples of statistical methods along with explanations of some of the advantages of the suggested methods of analysis. The analyses resulting from the application of methods described in this pra...
SCOPE
1.1 This practice describes methods for the statistical analysis of laboratory results obtained from interlaboratory proficiency testing programs. As in accordance with Practice E1301, proficiency testing is the use of interlaboratory comparisons for the determination of laboratory testing or measurement performance. Conversely, collaborative study (or collaborative trial) is the use of interlaboratory comparisons for the determination of the precision of a test method, as covered by Practice E691.  
1.1.1 Method A covers testing programs using single test results obtained by testing a single sample (each laboratory submits a single test result).  
1.1.2 Method B covers testing programs using paired test results obtained by testing two samples (each laboratory submits one test result for each of the two samples). The two samples should be of the same material or two materials similar enoug...

General Information

• Status: Historical
• Publication Date: 14-Nov-2016
• ICS: 71.040.40 - Chemical analysis
• Technical Committee: E11 - Quality and Statistics
• Drafting Committee: E11.20 - Test Method Evaluation and Quality Control

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E2489 −16 An American National Standard
Standard Practice for
Statistical Analysis of One-Sample and Two-Sample
1
Interlaboratory Proficiency Testing Programs
This standard is issued under the fixed designation E2489; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 Thispracticedescribesmethodsforthestatisticalanaly-
sis of laboratory results obtained from interlaboratory profi-
2. Referenced Documents
ciency testing programs. As in accordance with Practice
2
2.1 ASTM Standards:
E1301, proficiency testing is the use of interlaboratory com-
E177Practice for Use of the Terms Precision and Bias in
parisons for the determination of laboratory testing or mea-
ASTM Test Methods
surement performance. Conversely, collaborative study (or
E178Practice for Dealing With Outlying Observations
collaborativetrial)istheuseofinterlaboratorycomparisonsfor
E456Terminology Relating to Quality and Statistics
the determination of the precision of a test method, as covered
E691Practice for Conducting an Interlaboratory Study to
by Practice E691.
Determine the Precision of a Test Method
1.1.1 Method A covers testing programs using single test
E1301Guide for Proficiency Testing by Interlaboratory
results obtained by testing a single sample (each laboratory
3
Comparisons (Withdrawn 2012)
submits a single test result).
E2586Practice for Calculating and Using Basic Statistics
1.1.2 Method B covers testing programs using paired test
results obtained by testing two samples (each laboratory
3. Terminology
submits one test result for each of the two samples). The two
3.1 Definitions—The terminology defined in Terminology
samplesshouldbeofthesamematerialortwomaterialssimilar
E456 applies to this practice unless modified herein.
enough to have approximately the same degree of variation in
3.1.1 collaborative study, n—interlaboratory study in which
test results.
each laboratory uses the defined method of analysis to analyze
1.2 Methods A and B are applicable to proficiency testing
identical portions of homogeneous materials to assess the
programs containing a minimum of 10 participating laborato-
performance characteristics obtained for that method of
ries. 4
analysis. Horwitz
1.3 Themethodsprovidedirectionforassessingandcatego-
3.1.2 collaborative trial, n—see collaborative study.
rizing the performance of individual laboratories based on the
3.1.3 interlaboratory comparison, n—organization,
relative likelihood of occurrence of their test results, and for
performance,andevaluationoftestsonthesameorsimilartest
determining estimates of testing variation associated with
items by two or more laboratories in accordance with prede-
repeatability and reproducibility. Assumptions are that a ma-
termined conditions.
jority of the participating laboratories execute the test method
th
˜
3.1.4 median, X,n—the 50 percentile in a population or
properlyandthatsamplesareofsufficienthomogeneitythatthe
sample. E2586
testing results represent results obtained from each laboratory
3.1.4.1 Discussion—The sample median is the [(n + 1)⁄2]
testing essentially the same material. Each laboratory receives
order statistic if the sample size n is odd and is the average of
the same instructions or protocol.
the [n/2] and [n/2 + 1] order statistics if n is even.
1.4 This standard does not purport to address all of the
3.1.5 outlier, n—see outlying observation. E178
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
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
1
ThispracticeisunderthejurisdictionofASTMCommitteeE11onQualityand Standards volume information, refer to the standard’s Document Summary page on
Statistics and is the direct responsibility of Subcommittee E11.20 on Test Method the ASTM website.
3
Evaluation and Quality Control. The last approved version of this historical standard is referenced on
Current edition approved Nov. 15, 2016. Published November 2016. Originally www.astm.org.
4
approved in 2006. Last previous edition approved in 2011 as E2489–11. DOI: Horwitz, W., “Protocol for the Design, Conduct and Interpretation of Collab-
10.1520/E2489-16. orative Studies,” Pure and Applied Chemistry, Vol 60, No. 6, 1988, pp. 855–864.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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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: E2489 − 11 E2489 − 16 An American National Standard
Standard Practice for
Statistical Analysis of One-Sample and Two-Sample
1
Interlaboratory Proficiency Testing Programs
This standard is issued under the fixed designation E2489; 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 practice describes methods for the statistical analysis of laboratory results obtained from interlaboratory proficiency
testing programs. As in accordance with Practice E1301, proficiency testing is the use of interlaboratory comparisons for the
determination of laboratory testing or measurement performance. Conversely, collaborative study (or collaborative trial) is the use
of interlaboratory comparisons for the determination of the performance characteristics precision of a test method, as covered by
Practice E691.
1.1.1 Method A covers testing programs using single test results obtained by testing a single sample (each laboratory submits
a single test result).
1.1.2 Method B covers testing programs using paired test results obtained by testing two samples (each laboratory submits one
test result for each of the two samples). The two samples should be of the same material or two materials similar enough to have
approximately the same degree of variation in test results.
1.2 Methods A and B are applicable to proficiency testing programs containing a minimum of 10 participating laboratories.
1.3 The methods provide direction for assessing and categorizing the performance of individual laboratories based on the
relative likelihood of occurrence of their test results, and for determining estimates of testing variation associated with repeatability
and reproducibility. Assumptions are that a majority of the participating laboratories execute the test method properly and that
samples are of sufficient homogeneity that the testing results represent results obtained from each laboratory testing essentially the
same material. Each laboratory receives the same instructions or protocol.
1.4 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E178 Practice for Dealing With Outlying Observations
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
E1301 Guide for Proficiency Testing by Interlaboratory Comparisons (Withdrawn 2012)
E2586 Practice for Calculating and Using Basic Statistics
3. Terminology
3.1 Definitions:Definitions
3.1.1 The terminology defined in Terminology E456 applies to this practice unless modified herein.—The terminology defined
in Terminology E456 applies to this practice unless modified herein.
1
This practice is under the jurisdiction of ASTM Committee E11 on Quality and Statistics and is the direct responsibility of Subcommittee E11.20 on Test Method
Evaluation and Quality Control.
Current edition approved Oct. 1, 2011Nov. 15, 2016. Published October 2011November 2016. Originally approved in 2006. Last previous edition approved in 20062011
ε1
as E2489 – 06E2489 – 11. . DOI: 10.1520/E2489-11.10.1520/E2489-16.
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.
3
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E2489 − 16
3.1.1 collaborative study, n—interlaboratory study in which each laboratory uses the defined method of analysis to analyze
identical portions of homogeneous materials to assess the performance characteristics obtained for that method of analysis.
4
Horwitz
3.1.2 collaborative trial, n—see collaborative study.
3.1.3 interlaboratory comparison, n—organization, perfor
...