ASTM D4270-95(2001)

Standard Guide for Using Existing Practices in Developing and Writing Test Methods (Withdrawn 2009)

SIGNIFICANCE AND USE
There are enough existing practices related to the development of test methods or the preparation of one or more sections of new test methods so that even the experienced author may not use them as effectively as possible. This guide shows the person(s) preparing a new test method where and when the existing practices can best be used.
Using this standard as a guide, a task group should be able to prepare a draft of a new test in less time and with less effort than if this guide were not used. In addition, a well-prepared draft of a new test method is less likely to receive negative votes.
SCOPE
1.1 This guide is intended to assist task groups in the preparation of a test method. It can help the task group use existing statistically related ASTM practices more effectively during the development and writing of the test method.  
1.2 Some of the essential activities that should occur during the development of a new test method are not in existing or proposed practices under the jurisdiction of ASTM Subcommittee D13.93 on Statistics. This guide includes a brief explanation of how such activities should be carried out.  
1.3 This guide is applicable to properties that are evaluated by both parametric and nonparametric methods of estimation. The instructions on properties that are best evaluated by nonparametric methods are less complete than those for properties that are evaluated by parametric methods.
WITHDRAWN RATIONALE
This guide is intended to assist task groups in the preparation of a test method. It can help the task group use existing statistically related ASTM practices more effectively during the development and writing of the test method.
This guide is being withdrawn because D13 no longer has the expertise to maintain and statistical standards are being maintained by Committee E11.  
Formerly under the jurisdiction of Committee D13 on Textiles, this guide was withdrawn in February 2009.

General Information

• Status: Withdrawn
• Publication Date: 31-Dec-2000
• Withdrawal Date: 14-Jan-2009
• ICS: 59.080.01 - Textiles in general
• Technical Committee: D13 - Textiles

Relations

• Replaces: ASTM D4270-95 - Standard Guide for Using Existing Practices in Developing and Writing Test Methods
• Effective Date: 01-Jan-2001

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D4270–95 (Reapproved 2001)
Standard Guide for
Using Existing Practices in Developing and Writing Test
Methods
This standard is issued under the fixed designation D 4270; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 4855 Practice for Comparing Test Methods
E 456 Terminology Relating to Quality and Statistics
1.1 This guide is intended to assist task groups in the
E 691 Practice for Conducting an Interlaboratory Study to
preparation of a test method. It can help the task group use
Determine the Precision of a Test Method
existing statistically related ASTM practices more effectively
2.2 ASTM Adjuncts:
during the development and writing of the test method.
TEX-PAC
1.2 Some of the essential activities that should occur during
the development of a new test method are not in existing or
NOTE 1—TEX-PAC is a group of PC programs on floppy disk.
proposed practices under the jurisdiction of ASTM Subcom-
3. Terminology
mittee D13.93 on Statistics. This guide includes a brief
explanation of how such activities should be carried out.
3.1 Definitions:
1.3 This guide is applicable to properties that are evaluated
3.1.1 moving range, MR, n—the difference without regard
by both parametric and nonparametric methods of estimation.
to sign between two successive observations.
The instructions on properties that are best evaluated by
3.1.2 nonparametric, adj—in statistics, a term referring to a
nonparametric methods are less complete than those for
technique that is not based on assumptions about the nature of
properties that are evaluated by parametric methods.
the underlying frequency distribution. (Compare to paramet-
ric.)
2. Referenced Documents
3.1.3 parametric, adj—in statistics, a term referring to a
2.1 ASTM Standards:
techniquethatassumesthenatureoftheunderlyingdistribution
D 123 Terminology Relating to Textiles
is known. (Compare to nonparametric.)
D 2904 Practice for InterlaboratoryTesting of aTextileTest
3.1.4 practice, n—adefinitiveprocedureforperformingone
Method that Produces Normally Distributed Data
or more specific operations or functions that does not produce
D 2905 Practice for Statements on Number of Specimens
a test result.
for Textiles
3.1.4.1 Discussion—A practice is not a down-graded test
D 2906 Practice for Statements on Precision and Bias for
method.Examplesofpracticesincludeproceduresforconduct-
Textiles
ing interlaboratory testing programs or other statistical proce-
D 3777 Practice for Writing Specifications for Textiles
dures; for writing statements on sampling or precision and
D 4271 PracticeforWritingStatementsonSamplinginTest
accuracy; and for selection, preparation, application, inspec-
Methods for Textiles
tion, necessary precautions for use or disposal, installation,
D 4356 Practice for Establishing Consistent Test Method
maintenance, and operation of testing equipment.
Tolerances
3.1.5 test method, n—a definitive procedure for the identi-
D 4467 Practice for InterlaboratoryTesting of aTextileTest
fication, measurement, or evaluation of one or more qualities,
Method that Produces Non-Normally Distributed Data
characteristics, or properties of a material, product, system, or
D 4853 Guide for Reducing Test Variability
service that produces a test result.
D 4854 Guide for Estimating the Magnitude of Variability
3.1.6 For the definitions of other terms that appear in this
from Expected Sources in Sampling Plans
standard, refer to Terminology D 123 and Terminology E 456.
4. Summary of Guide
This guide is under the jurisdiction of ASTM Committee D13 on Textiles and
4.1 The guide is summarized in Fig. 1, which shows the
is the direct responsibility of Subcommittee D13.93 on Statistics.
steps in test method development, the sections of this guide
Current edition approved May 15, 1995. Published July 1995. Originally
published as D 4270 – 83. Last previous edition D 4270 – 90.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on PC programs on floppy disk are available through ASTM. For a 3 ⁄2 in. disk
the ASTM website. request PCN: 12-429040; for a 5 ⁄4 in. disk request PCN: 12-429041-18.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D4270–95 (2001)
When the results of a step are less than completely satisfactory, the reference
7. Evaluating Potential Methods
practice(s) should show to which of the previous steps the development of the test
method should revert.
7.1 Sources of Potential Methods—Potential procedures for
Step in a proposed new test method usually come from two sources:
Development Section(s) Other References
either one or more companies or laboratories have a method
that is being used by them, or someone has decided that a
Determining Need 6 none
Sources of Methods 7.1 none
specific procedure is a reasonable one to use even though it has
Applicability of Potential Methods 7.2 none
notbeenusedinindustry.Existingproceduresmaybemodified
Initial Test Method Tolerances 7.3 Practice D 4356
by the task group in the light of a consensus of viewpoints.
Reducing Variability 7.4 Practice D 4853
Statistical Control 7.5 none
7.2 Applicability of Potential Methods—The first job of the
Revised Test Method Tolerances 7.6 Practice D 4356
task group is to consider each of the potential methods and
Initial Draft(s) 8.1 Blue Book
D13.91 White Paper
determineifthemethodreallymeasuresthepropertyofinterest
Selecting Procedure to Use 8.2 Practice D 4855
or whether it measures some related property instead. A
Interlaboratory Testing 9 Practice D 2904
Practice D 4467
specific procedure can usually be investigated within a single
Practice E 691
laboratory. In the light of these findings, a judgment should be
Terminology 10.2 Terminology D 123
Terminology E 456 made whether each of the potential methods is worthy of
Uses and Significance 10.3 Practice D 2906
further work. In addition, if the method is supposed to predict
Sampling 10.4 Practice D 2905
performance in a later stage in the life of a material or product,
Practice D 3777
Practice D 4271
the task group needs to verify that the method will really do so.
Guide D 4854
At this point, the task group should eliminate any potential test
Precision and Bias 10.5 Practice D 2906
procedure that does not meet these requirements. If all of the
Blue Book
Review of Draft 11.1 none
potential procedures are eliminated, the task group should
Ballots 12.1 ASTM Regulations
make every reasonable attempt to discover or invent a proce-
FIG. 1 Suggested Steps in Test Method Development
dure that does meet these requirements. Failure to do so will
mean that the selected test method will not be as good as the
users have a right to expect.
which apply, and other references that may be used as aids in
7.3 Initial Test Method Tolerances—Practice D 4356 dis-
a specific step in the development of the test method. As Fig.
cusses the fact that the tolerances specified for each of the
1 points out, the references should show to which of the
measurements of some characteristic of a test specimen deter-
previous steps the development should revert when the results
mine the exactness with which a test result can realistically be
of a specific step are less than satisfactory.
reported. For example, a procedure for determining mass per
unitareaofafabricspecimenshouldrequirethatthelengthand
5. Significance and Use
width of the specimen be measured to within some tolerance
5.1 There are enough existing practices related to the
andthemasstowithinanothertolerance.Ifthesetolerancesare
development of test methods or the preparation of one or more
broad, it will not be realistic to require reporting the mass per
sections of new test methods so that even the experienced
unitareaquiteexactly.Beforestartingworkontheoneormore
author may not use them as effectively as possible. This guide
potential procedures that are still under consideration, the task
shows the person(s) preparing a new test method where and
group should select consistent test method tolerances.
when the existing practices can best be used.
7.4 Reducing Variability—It is quite likely that the results
5.2 Using this standard as a guide, a task group should be
for each of the potential test methods include variability that
able to prepare a draft of a new test in less time and with less
might be eliminated or reduced by changes in the procedure.
effort than if this guide were not used. In addition, a well-
Guide D 4853 discusses how to locate the sources of such
prepared draft of a new test method is less likely to receive
unnecessary variability and how to eliminate them by (1) using
negative votes.
ruggedness tests, (2) evaluating and using components of
variance, (3) averaging results from more than one specimen,
6. Determining Need for a Method
(4)compositingsamplespriortotesting,and(5)usingphysical
6.1 There is no simple answer to the question: “Is a new test
standards to reduce time related changes in the method or
method needed?” Generally, a new test method is needed if (1)
equipment. A brief description of ruggedness testing and a set
no ASTM test method exists to identify, measure, or evaluate
of references are given in Practice D 2904. The task group
one or more significant qualities, characteristics, or properties
shouldcontactapersonwithstatisticalexperienceforhelpwith
of a material, product, system, or service and (2) need for such
the methods of eliminating unnecessary variability listed
a method exists on an industry-wide basis. The responsible
above.
subcommitteeneedstobeconvincedthatatrueneedexistsand
7.5 Statistical Control—Useful testing procedures should
beagreedupontheexactnatureofthequality,characteristic,or
be in a state of statistical control; that is, the long-term
property of interest to be evaluated. It is essential that a test
method measure a quality, characteristic, or property that will variability should be no greater than is predicted from the
short-term variability. Guidance is given in 7.4 for detecting
predict the usefulness of a material, product, system, or service
when it is put to its intended use. and eliminating assignable causes of increased long-term
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