ASTM E2935-16
(Practice)Standard Practice for Conducting Equivalence Testing in Laboratory Applications
Standard Practice for Conducting Equivalence Testing in Laboratory Applications
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 not 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 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.
4.1.2 The equivalence limit, which represents a worst-case difference, is determined prior to the equivalence test and its value is usually set by consensus among subject-matter experts.
4.2 Two principal types of equivalence are covered in the practice, means equivalence and non-inferiority. Means equivalence implies that a sustained shift in test results between the modified and current testing processes refers to an absolute difference, meaning differences in either direction from zero. Non-inferiority is concerned with a difference only in the direction of an inferior outcome in a performance characteristic of the modified testing procedure versus the current testing procedure.
4.2.1 Equivalence testing is performed by an experiment that generates test results from the modified and current testing procedures on the same materials that are routinely tested. An exception is bias equivalence where the experiment consists of conducting multiple te...
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.
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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E2935 − 16 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 E456Terminology Relating to Quality and Statistics
E2282Guide for Defining the Test Result of a Test Method
1.1 This practice provides statistical methodology for con-
E2586Practice for Calculating and Using Basic Statistics
ducting equivalence testing on numerical data from two
3
2.2 USP Standard:
sources to determine if their true means or variances differ by
USP <1223> Validation of Alternative Microbiological
no more than predetermined limits.
Methods
1.2 Applications include (1) equivalence testing for bias
against an accepted reference value, (2) determining means
3. Terminology
equivalence of two test methods, test apparatus, instruments,
3.1 Definitions—See Terminology E456 for a more exten-
reagent sources, or operators within a laboratory or equiva-
sive listing of statistical terms.
lence of two laboratories in a method transfer, and (3)
3.1.1 accepted reference value, n—a value that serves as an
determiningnon-inferiorityofamodifiedtestprocedureversus
agreed-upon reference for comparison, and which is derived
a current test procedure with respect to a performance charac-
as: (1) a theoretical or established value, based on scientific
teristic.
principles, (2) an assigned or certified value, based on experi-
1.3 The guidance in this standard applies only to experi-
mental work of some national or international organization, or
mentsconductedonasinglematerialatagivenlevelofthetest
(3) a consensus or certified value, based on collaborative
result.
experimental work under the auspices of a scientific or
1.4 Guidance is given for determining the amount of data
engineering group. E177
required for an equivalence trial. The control of risks associ-
3.1.2 bias, n—the difference between the expectation of the
ated with the equivalence decision is discussed.
test results and an accepted reference value. E177
1.5 The values stated in SI units are to be regarded as
3.1.3 confidence interval, n—an interval estimate [L, U]
standard. No other units of measurement are included in this
with the statistics L and U as limits for the parameter θ and
standard.
withconfidencelevel1– α,wherePr(L≤θ≤U) ≥1– α. E2586
1.6 This standard does not purport to address all of the
3.1.3.1 Discussion—Theconfidencelevel,1– α,reflectsthe
safety concerns, if any, associated with its use. It is the proportion of cases that the confidence interval [L, U] would
responsibility of the user of this standard to establish appro-
containorcoverthetrueparametervalueinaseriesofrepeated
priate safety and health practices and determine the applica- random samples under identical conditions. Once L and U are
bility of regulatory limitations prior to use.
given values, the resulting confidence interval either does or
doesnotcontainit.Inthissense“confidence”appliesnottothe
2. Referenced Documents
particular interval but only to the long run proportion of cases
2
when repeating the procedure many times.
2.1 ASTM Standards:
E177Practice for Use of the Terms Precision and Bias in 3.1.4 confidence level, n—thevalue,1– α,oftheprobability
ASTM Test Methods associated with a confidence interval, often expressed as a
percentage. E2586
3.1.4.1 Discussion—α is generally a small number. Confi-
1
This test method is under the jurisdiction ofASTM Committee E11 on Quality dence level is often 95 % or 99 %.
and Statistics and is the direct responsibility of Subcommittee E11.20 on Test
3.1.5 confidence limit, n—each of the limits, L and U, of a
Method Evaluation and Quality Control.
confidence interval, or the limit of a one-sided confidence
Current edition approved Nov. 15, 2016. Published January 2017. Originally
approved in 2013. Last previous edition approved in 2015 as E2935 – 15. DOI:
interval. E2586
10.1520/E2935-16.
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
3
Standards volume information, refer to the standard’s Document Summary page on Available from U.S. Pharmacopeial Convention (USP), 12601 Twinbrook
the ASTM website. 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 − 16
3.1.6 degrees of freedom, n—the number of independent 3.1.23 te
...
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 − 15 E2935 − 16 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, laboratory or equivalence of two
laboratories in a method transfer, and (3) equivalence of two laboratories in a method transfer.determining non-inferiority of a
modified test procedure versus a current test procedure with respect to a performance characteristic.
1.3 The current guidance in this standard applies only to experiments conducted on a single material. Guidance is given for
determining the amount of data required for an equivalence trial.material at a given level of the test result.
1.4 The statistical methodologyGuidance is given for determining equivalence used is the two one-sided tests (TOST)
procedure.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 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
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
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] with the statistics L and U as limits for the parameter θ and with
confidence level 1 – α, where Pr(L ≤ θ ≤ U) ≥ 1– α. E2586
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 Oct. 1, 2015Nov. 15, 2016. Published October 2015January 2017. Originally approved in 2013. Last previous edition approved in 20142015 as
E2935 – 14.15. DOI: 10.1520/E2935-15.10.1520/E2935-16.
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
---------------------- Page: 1 ----------------------
E2935 − 16
3.1.3.1 Discussion—
The confidence level, 1 – α, reflects the proportion of cases that the confidence interval [L, U] would contain or cover the true
parameter value in a series of repeated random samples under identical conditions. Once L and U are given val
...
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