ASTM C670-24a
(Practice)Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
Standard Practice for Preparing Precision and Bias Statements for Test Methods for Construction Materials
ABSTRACT
This practice provides guidance in preparing precision and bias statements for ASTM test methods pertaining to construction materials. Test method shall conform to the maximum acceptable range of individual measurements. In order to be valid the indexes of precision to be included in the precision statement as guides for the operator must be based on estimates of the precision of the test method obtained from a statistically designed inter-laboratory series of tests. This series of tests must involve a sufficient number of laboratories, materials, and replicate measurements so that the results obtained provide reliable estimates of the true precision characteristic of the test method. The procedures described in this practice are based on the assumption that the proper estimates of precision have already been obtained. In any test method, tolerances are placed on the accuracy of measuring equipment. All tests made with a given set of equipment which has an error within the permitted tolerance will produce results with a small consistent bias, but that bias is not inherent in the test method and is not included in the bias statement for the test method. There are two conditions which permit the bias of a test method to be estimated: a standard reference sample of known value has been tested by the test method, and the test method has been applied to a sample which has been compounded in such a manner that the true value of the property being measured is known, such as may be the case, for example, in a test for cement content of concrete.
SCOPE
1.1 The Form and Style for ASTM Standards requires that all test methods contain statements on precision and bias. Further, the precision statement is required to contain a statement on single-operator precision (repeatability) and a statement on multilaboratory precision (reproducibility). This practice provides guidance for preparing precision and bias statements that comply with these requirements. Discussion of the purpose and significance of precision and bias statements for users of test methods is also provided. Examples of precision statements that conform to this practice are included in Appendix X1. This practice supplements Practice E177 and has been developed to meet the needs of ASTM Committees dealing with construction materials.
Note 1: Although this practice is under the jurisdiction of Committee C09, the current version was developed jointly by Committees C01 and C09 and has subsequently been adopted for use by other committees dealing with construction materials.
1.2 This practice assumes that an interlaboratory study (ILS) has been completed in accordance with Practice C802 or Practice E691. The interlaboratory study provides the necessary statistical values to write the precision and bias statements.
1.3 The system of units for this practice is not specified. Dimensional quantities in the practice are presented only in examples of precision and bias statements.
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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.
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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: C670 − 24a
Standard Practice for
Preparing Precision and Bias Statements for Test Methods
1
for Construction Materials
This standard is issued under the fixed designation C670; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.1 The Form and Style for ASTM Standards requires that
Barriers to Trade (TBT) Committee.
all test methods contain statements on precision and bias.
Further, the precision statement is required to contain a
2. Referenced Documents
statement on single-operator precision (repeatability) and a
2
statement on multilaboratory precision (reproducibility). This
2.1 ASTM Standards:
practice provides guidance for preparing precision and bias C802 Practice for Conducting an Interlaboratory Test Pro-
statements that comply with these requirements. Discussion of
gram to Determine the Precision of Test Methods for
the purpose and significance of precision and bias statements Construction Materials
for users of test methods is also provided. Examples of
C1067 Practice for Conducting a Ruggedness Evaluation or
precision statements that conform to this practice are included Screening Program for Test Methods for Construction
in Appendix X1. This practice supplements Practice E177 and Materials
has been developed to meet the needs of ASTM Committees D6607 Practice for Inclusion of Precision Statement Varia-
dealing with construction materials. tion in Specification Limits
E177 Practice for Use of the Terms Precision and Bias in
NOTE 1—Although this practice is under the jurisdiction of Committee
ASTM Test Methods
C09, the current version was developed jointly by Committees C01 and
E456 Terminology Relating to Quality and Statistics
C09 and has subsequently been adopted for use by other committees
dealing with construction materials.
E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.2 This practice assumes that an interlaboratory study
(ILS) has been completed in accordance with Practice C802 or
3. Terminology
Practice E691. The interlaboratory study provides the neces-
sary statistical values to write the precision and bias state-
3.1 Definitions:
ments.
3.1.1 For definitions of general statistical terms, refer to
Terminology E456.
1.3 The system of units for this practice is not specified.
3
Dimensional quantities in the practice are presented only in
3.2 Definitions of Terms Specific to This Standard:
examples of precision and bias statements.
3.2.1 test determination, n—the value of a characteristic of
1.4 This standard does not purport to address all of the a single test specimen obtained by a specified test method.
safety concerns, if any, associated with its use. It is the
3.2.1.1 Discussion—The term “replicate” is often used for
responsibility of the user of this standard to establish appro-
each test determination if multiple determinations are required
priate safety, health, and environmental practices and deter-
to obtain a test result (see 4.1).
mine the applicability of regulatory limitations prior to use.
3.2.2 test result, n—the value of a characteristic of a
1.5 This international standard was developed in accor-
material obtained by carrying out a specified test method.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the 3.2.2.1 Discussion—A test result may be a single test
1
This practice is under the jurisdiction of ASTM Committee C09 on Concrete
2
and Concrete Aggregates and is the direct responsibility of Subcommittee C09.94 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
on Evaluation of Data (Joint C09 and C01). contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Current edition approved Feb. 1, 2024. Published March 2024. Originally Standards volume information, refer to the standard’s Document Summary page on
approved in 1971. Last previous edition approved in 2024 as C670 – 24. DOI: the ASTM website.
3
10.1520/C0670-24A. Terms are listed in order of hierarchy beginning with the basic concept.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohoc
...
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: C670 − 24 C670 − 24a
Standard Practice for
Preparing Precision and Bias Statements for Test Methods
1
for Construction Materials
This standard is issued under the fixed designation C670; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope*
1.1 The Form and Style for ASTM Standards requires that all test methods contain statements on precision and bias. Further, the
precision statement is required to contain a statement on single-operator precision (repeatability) and a statement on
multilaboratory precision (reproducibility). This practice provides guidance for preparing precision and bias statements that
comply with these requirements. Discussion of the purpose and significance of precision and bias statements for users of test
methods is also provided. Examples of precision statements that conform to this practice are included in Appendix X1. This
practice supplements Practice E177 and has been developed to meet the needs of ASTM Committees dealing with construction
materials.
NOTE 1—Although this practice is under the jurisdiction of Committee C09, the current version was developed jointly by Committees C01 and C09 and
has subsequently been adopted for use by other committees dealing with construction materials.
1.2 This practice assumes that an interlaboratory study (ILS) has been completed in accordance with Practice C802 or Practice
E691. The interlaboratory study provides the necessary statistical values to write the precision and bias statements.
1.3 The system of units for this practice is not specified. Dimensional quantities in the practice are presented only in examples
of precision and bias statements.
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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 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:
C802 Practice for Conducting an Interlaboratory Test Program to Determine the Precision of Test Methods for Construction
Materials
1
This practice is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.94 on
Evaluation of Data (Joint C09 and C01).
Current edition approved Jan. 1, 2024Feb. 1, 2024. Published March 2024. Originally approved in 1971. Last previous edition approved in 20152024 as
C670 – 15.C670 – 24. DOI: 10.1520/C0670-24.10.1520/C0670-24A.
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.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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C670 − 24a
C1067 Practice for Conducting a Ruggedness Evaluation or Screening Program for Test Methods for Construction Materials
D6607 Practice for Inclusion of Precision Statement Variation in Specification Limits
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology
3.1 Definitions:
3.1.1 For definitions of general statistical terms, refer to Terminology E456.
3
3.2 Definitions of Terms Specific to This Standard:
3.2.1 test determination, n—the value of a characteristic of a single test specimen obtained by a specified test method.
3.2.1.1 Discussion—
The term “replicate” is often used for a test determination.each test determination if multiple determinations are req
...
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