ASTM D2777-21
(Practice)Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
Standard Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water
SIGNIFICANCE AND USE
5.1 Following this practice should result in precision-and-bias statements that can be achieved by any laboratory properly using the test method studied. These precision-and-bias statements provide the basis for generic limits for use in the Quality Control section of the test method. Optionally, the detection and quantitation values provide estimates of the level at which most laboratories should be able to achieve confident detection and meet the minimum precision (expressed as relative standard deviation) expected.
5.2 The method specifies the matrices for which the test method is appropriate. The collaborative test corroborates the write-up within the limitations of the test design. An extensive test can only use representative matrices so that universal applicability cannot be implied from the results.
5.3 The fundamental assumption of the collaborative study is that the matrices tested, the concentrations tested, and the participating laboratories are a representative and fair evaluation of the scope and applicability of the test method as written.
SCOPE
1.1 This practice establishes uniform standards for estimating and expressing the precision and bias of applicable test methods for Committee D19 on Water. Statements of precision and bias in test methods are required by the Form and Style for ASTM Standards, “Section A21. Precision and Bias (Mandatory).” In principle, all test methods are covered by this practice. However, the variability equations provided in this standard are applicable only to test methods that yield continuous function values.
1.2 Except as specified in 1.4, 1.5, and 1.6, this practice requires the task group proposing a new test method to carry out a collaborative study from which statements for precision (overall and single-operator standard-deviation estimates) and bias can be developed. This practice provides general guidance to task groups in planning and conducting such determinations of precision and bias.
1.3 This practice requires that a task group making a substantive revision to a test method also perform a limited-scale collaborative study (known as a ― comparability study) to evaluate the effect of the revision on the precision and bias statement. This practice provides guidance to task groups for conducting such limited-scale collaborative studies. Examples of substantive modifications may include, but are not limited to, changes in mandatory or allowable instrumentation, reagents, reaction times, etc.
1.3.1 Changes to applicable water matrices in the Scope of a method may constitute a substantive modification under this provision. Only matrices that have been evaluated in an approved collaborative study may be listed in the Scope of a method. It is recognized that the term “matrix” is generally vague. Terms specifying matrix types can cover significantly different chemical constituents, unless the matrix is synthesized to be of a standardized makeup. Substitute Wastewater (Practice D5905) is one such defined matrix. For purposes of this practice, the importance of this requirement is to assist the user of a D19 standard in determining the applicability of the method to their samples. Evaluated matrices should be described with as much detail as possible to minimize misapplication.
1.3.2 A method's concentration-range extension that is deemed to merit additional collaborative testing (even without a method modification that would otherwise be considered substantive) shall require a full collaborative study, as described in 7.1 through 7.5, but only at concentrations representative of the extended range. Note that such a collaborative study could involve as little as a single concentration study in a single reproducible matrix.
1.3.3 Whether a revision to a test method includes substantive modification shall be determined by consensus of the Committee.
1.4 If a full-scale collaborative study is not technically feasible, because...
General Information
Buy Standard
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: D2777 − 21
Standard Practice for
Determination of Precision and Bias of Applicable Test
1
Methods of Committee D19 on Water
This standard is issued under the fixed designation D2777; 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 this practice, the importance of this requirement is to assist the
user of a D19 standard in determining the applicability of the
1.1 This practice establishes uniform standards for estimat-
method to their samples. Evaluated matrices should be de-
ing and expressing the precision and bias of applicable test
scribed with as much detail as possible to minimize misappli-
methods for Committee D19 onWater. Statements of precision
cation.
and bias in test methods are required by the Form and Style for
ASTM Standards, “Section A21. Precision and Bias (Manda- 1.3.2 A method’s concentration-range extension that is
tory).” In principle, all test methods are covered by this deemed to merit additional collaborative testing (even without
practice. However, the variability equations provided in this a method modification that would otherwise be considered
standard are applicable only to test methods that yield continu- substantive) shall require a full collaborative study, as de-
ous function values.
scribed in 7.1 through 7.5, but only at concentrations represen-
tative of the extended range. Note that such a collaborative
1.2 Except as specified in 1.4, 1.5, and 1.6, this practice
study could involve as little as a single concentration study in
requires the task group proposing a new test method to carry
a single reproducible matrix.
out a collaborative study from which statements for precision
(overall and single-operator standard-deviation estimates) and 1.3.3 Whether a revision to a test method includes substan-
bias can be developed.This practice provides general guidance tive modification shall be determined by consensus of the
to task groups in planning and conducting such determinations
Committee.
of precision and bias.
1.4 If a full-scale collaborative study is not technically
1.3 This practice requires that a task group making a
feasible, because of the nature of the test method or instability
substantive revision to a test method also perform a limited-
of samples, the most complete collaborative study that is
scale collaborative study (known as a — comparability study)
technically feasible shall be conducted to provide the best
to evaluate the effect of the revision on the precision and bias
possible limited basis for estimating the overall and single-
statement. This practice provides guidance to task groups for
operator standard deviations. In some situations, an intermedi-
conducting such limited-scale collaborative studies. Examples
ate collaborative study as described in Guide D7847 may
of substantive modifications may include, but are not limited
provide an appropriate approach. It is recognized that there
to, changes in mandatory or allowable instrumentation,
may be circumstances when even a limited collaborative study
reagents, reaction times, etc.
is not feasible.Any collaborative study plan that does not meet
1.3.1 Changes to applicable water matrices in the Scope of
all the requirements spelled out in this practice will require a
a method may constitute a substantive modification under this
review and recommendation by the Results Advisor and an
provision. Only matrices that have been evaluated in an
approval by the D19 Technical Operations Section of the
approved collaborative study may be listed in the Scope of a
Executive Subcommittee.
method. It is recognized that the term “matrix” is generally
1.4.1 Examples of acceptable studies are the local-area
vague. Terms specifying matrix types can cover significantly
intermediate studies conducted by Subcommittee D19.24 on
different chemical constituents, unless the matrix is synthe-
microbiological methods because of inherent sample perish-
sized to be of a standardized makeup. Substitute Wastewater
ability. Such intermediate collaborative studies meet the same
(Practice D5905) is one such defined matrix. For purposes of
degrees of freedom and participant requirements as full col-
laborative studies. They involve six or more completely
1 independent local-area analysts who can begin analysis of
This practice is under the jurisdiction ofASTM Committee D19 on Water and
is the direct responsibility of Subcommittee D19.02 on Quality Systems,
unifor
...
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: D2777 − 13 D2777 − 21
Standard Practice for
Determination of Precision and Bias of Applicable Test
1
Methods of Committee D19 on Water
This standard is issued under the fixed designation D2777; 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 establishes uniform standards for estimating and expressing the precision and bias of applicable test methods for
Committee D19 on Water. Statements of precision and bias in test methods are required by the Form and Style for ASTM
Standards, “Section A21. Precision and Bias (Mandatory).” In principle, all test methods are covered by this practice. However,
the variability equations provided in this standard are applicable only to test methods that yield continuous function values.
1.2 Except as specified in 1.4, 1.5, and 1.6, this practice requires the task group proposing a new test method to carry out a
collaborative study from which statements for precision (overall and single-operator standard-deviation estimates) and bias can be
developed. This practice provides general guidance to task groups in planning and conducting such determinations of precision and
bias.
1.3 This practice also provides guidance to task groups for conducting limited-scale collaborative studies (known as
“comparability studies”) for test methods that have been revised, when such revision includes substantive modifications. requires
that a task group making a substantive revision to a test method also perform a limited-scale collaborative study (known as
a — comparability study) to evaluate the effect of the revision on the precision and bias statement. This practice provides guidance
to task groups for conducting such limited-scale collaborative studies. Examples of substantive modifications may include, but are
not limited to, changes in mandatory or allowable instrumentation, reagents, reaction times, etc.
1.3.1 Changes to applicable water matrices in the Scope of a method may constitute a substantive modification under this
provision. However, recognize that even the original Only matrices that have been evaluated in an approved collaborative study
may not have used all the various matrix types specified be listed in the Scope of a method. It is recognized that the term “matrix”
is generally vague. Terms specifying matrix types can cover significantly different chemical constituents, unless the matrix is
synthesized to be of a standardized makeup. Substitute Wastewater (Practice D5905in the method’s original Scope.) is one such
defined matrix. For purposes of this practice, the importance of this requirement is to assist the user of a D19 standard in
determining the applicability of the method to their samples. Evaluated matrices should be described with as much detail as
possible to minimize misapplication.
1.3.2 A method’s concentration-range extension that is deemed to merit additional collaborative testing (even without a method
modification that would otherwise be considered substantive) shall require a full collaborative study, as described in Sections7.1
7.1-through 7.5, but only at Youden-pair concentrations representative of the extended range. Note that such a collaborative study
could involve as little as a single-sample Youden-pairsingle concentration study in a single reproducible matrix.
1
This practice is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.02 on Quality Systems, Specification,
and Statistics.
Current edition approved Jan. 1, 2013Dec. 15, 2021. Published February 2013 June 2022. Originally approved in 1969. Last previous edition approved in 20122013 as
D2777 – 12.D2777 – 13. DOI: 10.1520/D2777-13.10.1520/D2777-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D2777 − 21
1.3.3 Whether a revision to a test method includes substantive modification shall be determined by consensus of the Committee.
1.4 If a full-scale collaborative study is not technically feasible, due tobecause of the nature of the test method or instability of
samples, the largest feasible scaled-down most complete collaborative study that is technically feasible shall be conducted to
provide the bes
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.