ASTM E2935-21
(Practice)Standard Practice for Evaluating Equivalence of Two Testing Processes
Standard Practice for Evaluating Equivalence of Two Testing Processes
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 studies are 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 te...
SCOPE
1.1 This practice provides statistical methodology for conducting equivalence studies on numerical data from two sources of test results to determine if their true means, variances, or other parameters differ by no more than predetermined limits.
1.2 Applications include (1) equivalence studies 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 either on a single material at a given level of the test result or on multiple materials covering a selected range of test results.
1.4 Guidance is given for determining the amount of data required for an equivalence study. 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 t...
General Information
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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: E2935 − 21 An American National Standard
Standard Practice for
1
Evaluating Equivalence of Two Testing Processes
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
1.1 This practice provides statistical methodology for con- 2.1 ASTM Standards:
ducting equivalence studies on numerical data from two E122PracticeforCalculatingSampleSizetoEstimate,With
Specified Precision, the Average for a Characteristic of a
sources of test results to determine if their true means,
variances, or other parameters differ by no more than prede- Lot or Process
E177Practice for Use of the Terms Precision and Bias in
termined limits.
ASTM Test Methods
1.2 Applications include (1) equivalence studies for bias
E456Terminology Relating to Quality and Statistics
against an accepted reference value, (2) determining means
E2282Guide for Defining the Test Result of a Test Method
equivalence of two test methods, test apparatus, instruments,
E2586Practice for Calculating and Using Basic Statistics
reagent sources, or operators within a laboratory or equiva-
E3080Practice for Regression Analysis with a Single Pre-
lence of two laboratories in a method transfer, and (3)
dictor Variable
determiningnon-inferiorityofamodifiedtestprocedureversus
3
2.2 USP Standard:
a current test procedure with respect to a performance charac-
USP <1223> Validation of Alternative Microbiological
teristic.
Methods
1.3 The guidance in this standard applies to experiments
conductedeitheronasinglematerialatagivenlevelofthetest 3. Terminology
resultoronmultiplematerialscoveringaselectedrangeoftest
3.1 Definitions—See Terminology E456 for a more exten-
results.
sive listing of statistical terms.
1.4 Guidance is given for determining the amount of data
3.1.1 accepted reference value, n—a value that serves as an
required for an equivalence study. The control of risks associ- agreed-upon reference for comparison, and which is derived
ated with the equivalence decision is discussed.
as: (1) a theoretical or established value, based on scientific
principles, (2) an assigned or certified value, based on experi-
1.5 The values stated in SI units are to be regarded as
mental work of some national or international organization, or
standard. No other units of measurement are included in this
(3) a consensus or certified value, based on collaborative
standard.
experimental work under the auspices of a scientific or
1.6 This standard does not purport to address all of the
engineering group. E177
safety concerns, if any, associated with its use. It is the
3.1.2 bias, n—the difference between the expectation of the
responsibility of the user of this standard to establish appro-
test results and an accepted reference value. E177
priate safety, health, and environmental practices and deter-
3.1.3 confidence interval, n—an interval estimate [L, U]
mine the applicability of regulatory limitations prior to use.
with the statistics L and U as limits for the parameter θ and
1.7 This international standard was developed in accor-
with confidence level 1 – α, where Pr(L ≤ θ ≤ U) ≥1– α.
dance with internationally recognized principles on standard-
E2586
ization established in the Decision on Principles for the
3.1.3.1 Discussion—Theconfidencelevel,1– α,reflectsthe
Development of International Standards, Guides and Recom-
proportion of cases that the confidence interval [L, U] would
mendations issued by the World Trade Organization Technical
containorcoverthetrueparametervalueinaseriesofrepeated
Barriers to Trade (TBT) Committee.
random samples under identical conditions. Once L and U are
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 June 1, 2021. Published June 2021. Originally the ASTM website.
ɛ1 3
approved in 2013. Last previous edition approved in 2020 as E2935 – 20 . DOI: Available from U.S. Pharmacopeial Convention (USP), 12601 Twinbrook
10.1520/E2935-21. Pkwy., Rockville, MD 20852-1790, http://www.usp.org.
Copyright © ASTM International, 100
...
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.
´1
Designation: E2935 − 20 E2935 − 21 An American National Standard
Standard Practice for
Conducting Equivalence Tests for Comparing Evaluating
1
Equivalence of Two Testing Processes
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
ε NOTE—Terms were corrected editorially in May 2021.
1. Scope
1.1 This practice provides statistical methodology for conducting equivalence testingstudies on numerical data from two sources
of test results to determine if their true means, variances, or other parameters differ by no more than predetermined limits.
1.2 Applications include (1) equivalence testingstudies 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 either on a single material at a given level of the test result
or on multiple materials covering a selected range of test results.
1.4 Guidance is given for determining the amount of data required for an equivalence trial.study. 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 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:
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
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 July 1, 2020June 1, 2021. Published August 2020June 2021. Originally approved in 2013. Last previous edition approved in 20172020 as E2935
ɛ1
– 17.20 . DOI: 10.1520/E2935-20E01.10.1520/E2935-21.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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E2935 − 21
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 with a Single Predictor Variable
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
3.1.3 confidence interval, n—an interval estimate [L, U]
...
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