ASTM E2935-17
(Practice)Standard Practice for Conducting Equivalence Testing in Laboratory Applications
Standard Practice for Conducting Equivalence Testing in Laboratory Applications
ABSTRACT
This practice provides statistical methodology for conducting equivalence testing on numerical data from two sources to determine if their true means or variances differ by no more than predetermined limits. This standard provides guidance on experiments and statistical methods needed to demonstrate that the test results from a modified testing process are equivalent to those from the current testing process, where equivalence is defined as agreement within a prescribed limit, termed an equivalence limit.
SIGNIFICANCE AND USE
4.1 Laboratories conducting routine testing have a continuing need to make improvements in their testing processes. In these situations it must be demonstrated that any changes will neither cause an undesirable shift in the test results from the current testing process nor substantially affect a performance characteristic of the test method. This standard provides guidance on experiments and statistical methods needed to demonstrate that the test results from a modified testing process are equivalent to those from the current testing process, where equivalence is defined as agreement within a prescribed limit, termed an equivalence limit.
4.1.1 The equivalence limit, which represents a worst-case difference or ratio, is determined prior to the equivalence test and its value is usually set by consensus among subject-matter experts.
4.1.2 Examples of modifications to the testing process include, but are not limited, to the following:
(1) Changes to operating levels in the steps of the test method procedure,
(2) Installation of new instruments, apparatus, or sources of reagents and test materials,
(3) Evaluation of new personnel performing the testing, and
(4) Transfer of testing to a new location.
4.1.3 Examples of performance characteristics directly applicable to the test method include bias, precision, sensitivity, specificity, linearity, and range. Additional characteristics are test cost and elapsed time needed to conduct the test procedure.
4.2 Equivalence testing is performed by a designed experiment that generates test results from the modified and current testing procedures on the same types of materials that are routinely tested. The design of the experiment depends on the type of equivalence needed as discussed below. Experiment design and execution for various objectives is discussed in Section 5.
4.2.1 Means equivalence is concerned with a potential shift in the mean test result in either direction due to a modification in the tes...
SCOPE
1.1 This practice provides statistical methodology for conducting equivalence testing on numerical data from two sources to determine if their true means or variances differ by no more than predetermined limits.
1.2 Applications include (1) equivalence testing for bias against an accepted reference value, (2) determining means equivalence of two test methods, test apparatus, instruments, reagent sources, or operators within a laboratory or equivalence of two laboratories in a method transfer, and (3) determining non-inferiority of a modified test procedure versus a current test procedure with respect to a performance characteristic.
1.3 The guidance in this standard applies to experiments conducted on a single material at a given level of the test result or on multiple materials covering a range of selected test results.
1.4 Guidance is given for determining the amount of data required for an equivalence trial. The control of risks associated with the equivalence decision is discussed.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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...
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Designation: E2935 − 17 An American National Standard
Standard Practice for
1
Conducting Equivalence Testing in Laboratory Applications
This standard is issued under the fixed designation E2935; 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 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This practice provides statistical methodology for con-
E177Practice for Use of the Terms Precision and Bias in
ducting equivalence testing on numerical data from two
ASTM Test Methods
sources to determine if their true means or variances differ by
E456Terminology Relating to Quality and Statistics
no more than predetermined limits.
E2282Guide for Defining the Test Result of a Test Method
1.2 Applications include (1) equivalence testing for bias
E2586Practice for Calculating and Using Basic Statistics
against an accepted reference value, (2) determining means
E3080Practice for Regression Analysis
equivalence of two test methods, test apparatus, instruments, 3
2.2 USP Standard:
reagent sources, or operators within a laboratory or equiva-
USP <1223> Validation of Alternative Microbiological
lence of two laboratories in a method transfer, and (3)
Methods
determiningnon-inferiorityofamodifiedtestprocedureversus
a current test procedure with respect to a performance charac-
3. Terminology
teristic.
3.1 Definitions—See Terminology E456 for a more exten-
sive listing of statistical terms.
1.3 The guidance in this standard applies to experiments
conductedonasinglematerialatagivenlevelofthetestresult 3.1.1 accepted reference value, n—a value that serves as an
agreed-upon reference for comparison, and which is derived
or on multiple materials covering a range of selected test
results. as: (1) a theoretical or established value, based on scientific
principles, (2) an assigned or certified value, based on experi-
1.4 Guidance is given for determining the amount of data
mental work of some national or international organization, or
required for an equivalence trial. The control of risks associ-
(3) a consensus or certified value, based on collaborative
ated with the equivalence decision is discussed.
experimental work under the auspices of a scientific or
1.5 The values stated in SI units are to be regarded as engineering group. E177
standard. No other units of measurement are included in this
3.1.2 bias, n—the difference between the expectation of the
standard.
test results and an accepted reference value. E177
1.6 This standard does not purport to address all of the 3.1.3 confidence interval, n—an interval estimate [L, U]
safety concerns, if any, associated with its use. It is the
with the statistics L and U as limits for the parameter θ and
responsibility of the user of this standard to establish appro- with confidence level 1 – α, where Pr(L ≤ θ ≤ U) ≥1– α.
priate safety, health, and environmental practices and deter-
E2586
mine the applicability of regulatory limitations prior to use. 3.1.3.1 Discussion—Theconfidencelevel,1–α,reflectsthe
proportion of cases that the confidence interval [L, U] would
1.7 This international standard was developed in accor-
containorcoverthetrueparametervalueinaseriesofrepeated
dance with internationally recognized principles on standard-
random samples under identical conditions. Once L and U are
ization established in the Decision on Principles for the
given values, the resulting confidence interval either does or
Development of International Standards, Guides and Recom-
doesnotcontainit.Inthissense“confidence”appliesnottothe
mendations issued by the World Trade Organization Technical
particular interval but only to the long run proportion of cases
Barriers to Trade (TBT) Committee.
when repeating the procedure many times.
1 2
This test method is under the jurisdiction ofASTM Committee E11 on Quality For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Statistics and is the direct responsibility of Subcommittee E11.20 on Test contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Method Evaluation and Quality Control. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Oct. 1, 2017. Published November 2017. Originally the ASTM website.
3
approved in 2013. Last previous edition approved in 2016 as E2935 – 16. DOI: Available from U.S. Pharmacopeial Convention (USP), 12601 Twinbrook
10.1520/E2935-17. Pkwy., Rockville, MD 20852-1790, http://www.usp.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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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: E2935 − 16 E2935 − 17 An American National Standard
Standard Practice for
1
Conducting Equivalence Testing in Laboratory Applications
This standard is issued under the fixed designation E2935; 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 provides statistical methodology for conducting equivalence testing on numerical data from two sources to
determine if their true means or variances differ by no more than predetermined limits.
1.2 Applications include (1) equivalence testing for bias against an accepted reference value, (2) determining means equivalence
of two test methods, test apparatus, instruments, reagent sources, or operators within a laboratory or equivalence of two
laboratories in a method transfer, and (3) determining non-inferiority of a modified test procedure versus a current test procedure
with respect to a performance characteristic.
1.3 The guidance in this standard applies only to experiments conducted on a single material at a given level of the test
result.result or on multiple materials covering a range of selected test results.
1.4 Guidance is given for determining the amount of data required for an equivalence trial. The control of risks associated with
the equivalence decision is discussed.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.7 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:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E2282 Guide for Defining the Test Result of a Test Method
E2586 Practice for Calculating and Using Basic Statistics
E3080 Practice for Regression Analysis
3
2.2 USP Standard:
USP <1223> Validation of Alternative Microbiological Methods
3. Terminology
3.1 Definitions—See Terminology E456 for a more extensive listing of statistical terms.
3.1.1 accepted reference value, n—a value that serves as an agreed-upon reference for comparison, and which is derived as: (1)
a theoretical or established value, based on scientific principles, (2) an assigned or certified value, based on experimental work of
some national or international organization, or (3) a consensus or certified value, based on collaborative experimental work under
the auspices of a scientific or engineering group. E177
3.1.2 bias, n—the difference between the expectation of the test results and an accepted reference value. E177
1
This test method 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 Nov. 15, 2016Oct. 1, 2017. Published January 2017November 2017. Originally approved in 2013. Last previous edition approved in 20152016
as E2935 – 15.16. DOI: 10.1520/E2935-16.10.1520/E2935-17.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from U.S. Pharmacopeial Convention (USP), 12601 Twinbrook Pkwy., Rockville, MD 20852-1790, http://www.usp.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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E2935 − 17
3.1.3 confidence interval, n—an interval estimate [L, U] with the statistics L and U as limits for the parameter θ and with
confidence level 1 – α, where Pr(L ≤ θ ≤ U) ≥ 1– 1 – α. E2586
3.1.3.1 Discussion—
The confidence level, 1 –
...
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