ASTM D6631-05(2019)
(Guide)Standard Guide for Committee D01 for Conducting an Interlaboratory Study for the Purpose of Determining the Precision of a Test Method
Standard Guide for Committee D01 for Conducting an Interlaboratory Study for the Purpose of Determining the Precision of a Test Method
SIGNIFICANCE AND USE
3.1 The purpose of an interlaboratory evaluation, as defined in this guide, is to determine the variability of results obtained in different laboratories on equivalent equipment using a prescribed test method.
3.2 The definitions of statistical terms used in this guide are contained in Terminology E456.
SCOPE
1.1 This guide covers a simplified statistical procedure for planning and conducting interlaboratory evaluations of test methods.
1.2 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.
General Information
Relations
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: D6631 − 05 (Reapproved 2019)
Standard Guide for
Committee D01 for Conducting an Interlaboratory Study for
the Purpose of Determining the Precision of a Test Method
This standard is issued under the fixed designation D6631; 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 current limits of both the software, and the statistical protocols
currently available, this effectively restricts the use of this
1.1 This guide covers a simplified statistical procedure for
guide to test methods which yield results that are continuous.
planning and conducting interlaboratory evaluations of test
This generally means a measured quantity, such as pH or
methods.
brightness. Results that are discrete (such as counts or pass-
1.2 This international standard was developed in accor-
fail), or ordered (ranked), present three special problems in the
dance with internationally recognized principles on standard-
creation of a meaningful precision statement:
ization established in the Decision on Principles for the
4.1.1 The amount of information contained in discrete and
Development of International Standards, Guides and Recom-
ordereddataismuchlessthanincontinuousdata,necessitating
mendations issued by the World Trade Organization Technical
the collection of much more data.
Barriers to Trade (TBT) Committee.
4.1.2 The sensitivity (the ability to discriminate between
similar samples) is much less in discrete and ordered data than
2. Referenced Documents
continuous data.
2.1 ASTM Standards:
4.1.3 Since the precision statement relies on the normal
E177 Practice for Use of the Terms Precision and Bias in
distribution, and the distributions of discrete and ordered data
ASTM Test Methods
are usually decidedly non-normal, the normal precision state-
E456 Terminology Relating to Quality and Statistics
ment is invalid.
E691 Practice for Conducting an Interlaboratory Study to
4.2 Given these concerns with discrete and ordered data, a
Determine the Precision of a Test Method
simple statement of the results obtained in these types of
E1345 Practice for Reducing the Effect of Variability of
studies might be the most useful information for a prospective
Color Measurement by Use of Multiple Measurements
user of a test method.
3. Significance and Use
5. Preliminary
3.1 The purpose of an interlaboratory evaluation, as defined
5.1 Flow chart the test method.
in this guide, is to determine the variability of results obtained
in different laboratories on equivalent equipment using a
5.2 Survey known sources of information related to the test
prescribed test method.
method to establish how results are affected by variations in
operating conditions, atmospheric conditions, differences be-
3.2 The definitions of statistical terms used in this guide are
tween operators, etc. Select what appears to be the optimum
contained in Terminology E456.
procedure.
4. Problem Formulation
5.3 Provide instructions for the test method and, without
4.1 The objective of the evaluation should be to clearly comment, observe a laboratory technician perform a test
define the expected precision of the test method. Within the according to these instructions. Revise any parts of the draft
causing difficulty.
1 5.4 If desirable, make a comparative study with other test
This guide is under the jurisdiction of ASTM Committee D01 on Paint and
Related Coatings, Materials, and Applications and is the direct responsibility of methods for measuring the property by using specimens with a
Subcommittee D01.20 on Quality Assurance and Statistics.
wide range of values of the property under test (and possibly
Current edition approved June 1, 2019. Published June 2019. Originally
with wide ranges in other properties).
approved in 2001. Last previous edition approved in 2015 as D6631 – 05 (2015).
DOI: 10.1520/D6631-05R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Preparation for Interlaboratory Study
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Prepare a clear statement of the type of information
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. required from the interlaboratory evaluation.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6631 − 05 (2019)
6.2 Based on the study made in one laboratory (Section 5), reproducibility. (It must be emphasized that the word “differ-
prepare a proposed master plan for the interlaboratory evalu- ent” in this section, could apply to multiple manufacturers, or
ation. Discuss the plan, in an open meeting, if possible, with models of equipment.) However, different equipment, using
other participants in the study. different techniques or protocols for measurement, for
example, rotational and efflux cup viscometers, must NOT be
6.3 Select the materials to be used in the interlaboratory
used in the same study.
evaluations so as to:
10.1.4 Replicates—Each evaluation must at least be run in
6.3.1 Cover the applicable range of the property or compo-
duplicate.
nent to be measured, and
6.3.2 Represent as many classes of materials as feasible, to
10.2 Intralaboratory Precision is usually ascertained by
which the test method will be applied. having repeats made over the shortest possible time, preferably
the same day. If considered desirable, a completely unbiased
7. Pilot Evaluation
estimate of intralaboratory error can be obtained by use of
“blind” repetition. In this procedure two samples of at least
7.1 If the test method is new or the procedure for an old test
method is greatly altered, a pilot study by one laboratory one,andpreferablymore,ofthetestmaterialsaredistributedas
separate materials. If all the materials are duplicated, the total
involving a few materials (two or three) may reveal seriously
misleading directions in the written procedure. A Box and amount of work can be kept the same by not repeating the test
at another time. However, elimination of the time variable
Whisker Plot (as outlined in Practice E1345), or a Violin Plot
may help to clarify this evaluation. might alert cooperators to the use of blind repetition which, in
any event, is not readily applicable when all the test materials
8. Participating Laboratory Qualification
differ markedly in properties.
8.1 It is important that the managers of proposed partici-
10.3 For analytical test methods, the precision of which is
p
...
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6631 − 05 (Reapproved 2019)
Standard Guide for
Committee D01 for Conducting an Interlaboratory Study for
the Purpose of Determining the Precision of a Test Method
This standard is issued under the fixed designation D6631; 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 current limits of both the software, and the statistical protocols
currently available, this effectively restricts the use of this
1.1 This guide covers a simplified statistical procedure for
guide to test methods which yield results that are continuous.
planning and conducting interlaboratory evaluations of test
This generally means a measured quantity, such as pH or
methods.
brightness. Results that are discrete (such as counts or pass-
1.2 This international standard was developed in accor-
fail), or ordered (ranked), present three special problems in the
dance with internationally recognized principles on standard-
creation of a meaningful precision statement:
ization established in the Decision on Principles for the
4.1.1 The amount of information contained in discrete and
Development of International Standards, Guides and Recom-
ordered data is much less than in continuous data, necessitating
mendations issued by the World Trade Organization Technical
the collection of much more data.
Barriers to Trade (TBT) Committee.
4.1.2 The sensitivity (the ability to discriminate between
similar samples) is much less in discrete and ordered data than
2. Referenced Documents
continuous data.
2.1 ASTM Standards:
4.1.3 Since the precision statement relies on the normal
E177 Practice for Use of the Terms Precision and Bias in
distribution, and the distributions of discrete and ordered data
ASTM Test Methods
are usually decidedly non-normal, the normal precision state-
E456 Terminology Relating to Quality and Statistics
ment is invalid.
E691 Practice for Conducting an Interlaboratory Study to
4.2 Given these concerns with discrete and ordered data, a
Determine the Precision of a Test Method
simple statement of the results obtained in these types of
E1345 Practice for Reducing the Effect of Variability of
studies might be the most useful information for a prospective
Color Measurement by Use of Multiple Measurements
user of a test method.
3. Significance and Use
5. Preliminary
3.1 The purpose of an interlaboratory evaluation, as defined
5.1 Flow chart the test method.
in this guide, is to determine the variability of results obtained
in different laboratories on equivalent equipment using a
5.2 Survey known sources of information related to the test
prescribed test method.
method to establish how results are affected by variations in
operating conditions, atmospheric conditions, differences be-
3.2 The definitions of statistical terms used in this guide are
tween operators, etc. Select what appears to be the optimum
contained in Terminology E456.
procedure.
4. Problem Formulation
5.3 Provide instructions for the test method and, without
4.1 The objective of the evaluation should be to clearly comment, observe a laboratory technician perform a test
define the expected precision of the test method. Within the according to these instructions. Revise any parts of the draft
causing difficulty.
1 5.4 If desirable, make a comparative study with other test
This guide is under the jurisdiction of ASTM Committee D01 on Paint and
Related Coatings, Materials, and Applications and is the direct responsibility of methods for measuring the property by using specimens with a
Subcommittee D01.20 on Quality Assurance and Statistics.
wide range of values of the property under test (and possibly
Current edition approved June 1, 2019. Published June 2019. Originally
with wide ranges in other properties).
approved in 2001. Last previous edition approved in 2015 as D6631 – 05 (2015).
DOI: 10.1520/D6631-05R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 6. Preparation for Interlaboratory Study
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1 Prepare a clear statement of the type of information
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. required from the interlaboratory evaluation.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6631 − 05 (2019)
6.2 Based on the study made in one laboratory (Section 5), reproducibility. (It must be emphasized that the word “differ-
prepare a proposed master plan for the interlaboratory evalu- ent” in this section, could apply to multiple manufacturers, or
ation. Discuss the plan, in an open meeting, if possible, with models of equipment.) However, different equipment, using
other participants in the study. different techniques or protocols for measurement, for
example, rotational and efflux cup viscometers, must NOT be
6.3 Select the materials to be used in the interlaboratory
used in the same study.
evaluations so as to:
10.1.4 Replicates—Each evaluation must at least be run in
6.3.1 Cover the applicable range of the property or compo-
duplicate.
nent to be measured, and
6.3.2 Represent as many classes of materials as feasible, to 10.2 Intralaboratory Precision is usually ascertained by
which the test method will be applied. having repeats made over the shortest possible time, preferably
the same day. If considered desirable, a completely unbiased
7. Pilot Evaluation
estimate of intralaboratory error can be obtained by use of
7.1 If the test method is new or the procedure for an old test “blind” repetition. In this procedure two samples of at least
one, and preferably more, of the test materials are distributed as
method is greatly altered, a pilot study by one laboratory
involving a few materials (two or three) may reveal seriously separate materials. If all the materials are duplicated, the total
amount of work can be kept the same by not repeating the test
misleading directions in the written procedure. A Box and
Whisker Plot (as outlined in Practice E1345), or a Violin Plot at another time. However, elimination of the time variable
might alert cooperators to the use of blind repetition which, in
may help to clarify this evaluation.
any event, is not readily applicable when all the test materials
8. Participating Laboratory Qualification
differ markedly in properties.
8.1 It is important that the managers of proposed partici-
10.3 For analytical test methods, the precision of which is
pants in an interlaboratory study be aware of the capability of
usually very good, two repeats each in duplicat
...
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: D6631 − 05 (Reapproved 2015) D6631 − 05 (Reapproved 2019)
Standard Guide for
Committee D01 for Conducting an Interlaboratory Study for
the Purpose of Determining the Precision of a Test Method
This standard is issued under the fixed designation D6631; 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 guide covers a simplified statistical procedure for planning and conducting interlaboratory evaluations of test methods.
1.2 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
2.1 ASTM Standards:
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
E1345 Practice for Reducing the Effect of Variability of Color Measurement by Use of Multiple Measurements
3. Significance and Use
3.1 The purpose of an interlaboratory evaluation, as defined in this guide, is to determine the variability of results obtained in
different laboratories on equivalent equipment using a prescribed test method.
3.2 The definitions of statistical terms used in this guide are contained in Terminology E456.
4. Problem Formulation
4.1 The objective of the evaluation should be to clearly define the expected precision of the test method. Within the current
limits of both the software, and the statistical protocols currently available, this effectively restricts the use of this guide to test
methods which yield results that are continuous. This generally means a measured quantity, such as pH or brightness. Results that
are discrete (such as counts or pass-fail), or ordered (ranked), present three special problems in the creation of a meaningful
precision statement:
4.1.1 The amount of information contained in discrete and ordered data is much less than in continuous data, necessitating the
collection of much more data.
4.1.2 The sensitivity (the ability to discriminate between similar samples) is much less in discrete and ordered data than
continuous data.
4.1.3 Since the precision statement relies on the normal distribution, and the distributions of discrete and ordered data are
usually decidedly non-normal, the normal precision statement is invalid.
4.2 Given these concerns with discrete and ordered data, a simple statement of the results obtained in these types of studies
might be the most useful information for a prospective user of a test method.
5. Preliminary
5.1 Flow chart the test method.
This guide is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of Subcommittee
D01.20 on Quality Assurance and Statistics.
Current edition approved Dec. 1, 2015June 1, 2019. Published December 2015June 2019. Originally approved in 2001. Last previous edition approved in 20112015 as
D6631 – 05 (2011).(2015). DOI: 10.1520/D6631-05R15.10.1520/D6631-05R19.
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
D6631 − 05 (2019)
5.2 Survey known sources of information related to the test method to establish how results are affected by variations in
operating conditions, atmospheric conditions, differences between operators, etc. Select what appears to be the optimum procedure.
5.3 Provide instructions for the test method and, without comment, observe a laboratory technician perform a test according to
these instructions. Revise any parts of the draft causing difficulty.
5.4 If desirable, make a comparative study with other test methods for measuring the property by using specimens with a wide
range of values of the property under test (and possibly with wide ranges in other properties).
6. Preparation for Interlaboratory Study
6.1 Prepare a clear statement of the type of information required from the interlaboratory evaluation.
6.2 Based on the study made in one laboratory (Section 5), prepare a proposed master plan for the interlaboratory evaluation.
Discuss the plan, in an open meeting, if possible, with other participants in the study.
6.3 Select the materials to be used in the interlaboratory evaluations so as to:
6.3.1 Cover the applicable range of the property or component to be measured, and
6.3.2 Represent as many classes of materials as feasible, to which the test method will be applied.
7. Pilot Evaluation
7.1 If the test method is new or the procedure for an old test method is greatly altered, a pilot study by one laboratory involving
a few materials (two or three) may reveal seriously misleading directions in the written procedure. A Box and Whisker Plot (as
outlined in Practice E1345), or a Violin Plot may help to clarify this evaluation.
8. Participating Laboratory Qualification
8.1 It is important that the managers of proposed participants in an interlaboratory study be aware of the capability of those
participants to run the method under study. This is not the responsibility of the originator of the study, or ASTM. A Box and
Whisker Plot will also be helpful in this qualification protocol.
9. First Interlaboratory Evaluation
9.1 For the first interlaboratory evaluation use at least three materials to cover the expected range in property values and include
all of the laboratories that will participate in the main interlaboratory evaluation. This evaluation will clarify the procedure,
eliminate laboratories that do not comply with the procedure because of nonstandard conditions or equipment and, together with
the main study, give some idea of-the time constancy of laboratory results.
10. Main Interlaboratory Evaluation
10.1 Variables—The major variables that can be included in an interlaboratory evaluation of a test method are: materials,
laboratories, apparatus, and replicates, described as follows: (In the event that the minimums for these variables cannot be met,
it is advisable that the recommendation in 4.2 be consi
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.