ASTM D7778-15

Standard Guide for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

SIGNIFICANCE AND USE
5.1 All ASTM standard test methods are required to include statements on precision and bias. To obtain such data it is necessary to conduct an interlaboratory study. This document is designed to provide a brief overview of the steps necessary in an ILS and to suggest an appropriate sequence in carrying out these steps.  
5.1.1 Qualitative tests such as Test Method D130 copper corrosion may not require an ILS.
SCOPE
1.1 This guide describes the procedures for planning and conducting an interlaboratory study (ILS) of a test method used in Petroleum Products and Lubricants Committee D02 of ASTM for the purpose of estimating repeatability and reproducibility of the test method in accordance with ASTM Form and Style requirements.  
1.2 This guide is concerned with the management of the ILS and intended to provide guidance for the planning stage and ensure the process, logistics, and tools are identified and agreed upon in advance.  
1.2.1 Selection of the samples and the impact of sample selection on the final scope of the test method—both the range of materials covered in the scope and precision sections and the measurement range covered in the precision section—are important, and careful consideration needs to be given to these aspects before an ILS is launched.  
1.3 This guide does not concern itself with the development of test methods but rather with gathering the information needed for a test method precision statement.  
1.4 This guide is concerned with test methods which yield a single numerical figure as the test result, although the single figure may be the result of a calculation from a set of measurements.  
1.5 This guide is designed for tests of properties that are stable, such that bulk samples can be homogenized and sub-samples can be prepared that will be identical and stable for the duration of the ILS testing period. This guide is not designed for unstable properties or for properties that make it difficult to obtain stable, representative samples for an ILS conducted at multiple laboratory sites.  
1.6 This guide represents the suggested practices for a typical precision study. Individual subcommittees may modify this approach as their expertise directs.  
1.7 This guide is voluntary, and thus, is not required for an approved precision study.

General Information

• Status: Historical
• Publication Date: 31-Mar-2015
• ICS: 75.080 - Petroleum products in general
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.94 - Coordinating Subcommittee on Quality Assurance and Statistics

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: D7778 − 15 An American National Standard
Standard Guide for
Conducting an Interlaboratory Study to Determine the
1
Precision of a Test Method
This standard is issued under the fixed designation D7778; 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* 1.7 This guide is voluntary, and thus, is not required for an
approved precision study.
1.1 This guide describes the procedures for planning and
conductinganinterlaboratorystudy(ILS)ofatestmethodused
2. Referenced Documents
in Petroleum Products and Lubricants Committee D02 of
2
2.1 ASTM Standards:
ASTM for the purpose of estimating repeatability and repro-
D130 Test Method for Corrosiveness to Copper from Petro-
ducibility of the test method in accordance with ASTM Form
leum Products by Copper Strip Test
and Style requirements.
D4306 Practice for Aviation Fuel Sample Containers for
1.2 ThisguideisconcernedwiththemanagementoftheILS
Tests Affected by Trace Contamination
and intended to provide guidance for the planning stage and
D5854 Practice for Mixing and Handling of Liquid Samples
ensuretheprocess,logistics,andtoolsareidentifiedandagreed
of Petroleum and Petroleum Products
upon in advance.
D6300 Practice for Determination of Precision and Bias
1.2.1 Selection of the samples and the impact of sample
Data for Use in Test Methods for Petroleum Products,
selection on the final scope of the test method—both the range
Liquid Fuels, and Lubricants
ofmaterialscoveredinthescopeandprecisionsectionsandthe
D6708 Practice for StatisticalAssessment and Improvement
measurement range covered in the precision section—are
of Expected Agreement Between Two Test Methods that
important, and careful consideration needs to be given to these
Purport to Measure the Same Property of a Material
aspects before an ILS is launched.
D6792 Practice for Quality Management Systems in Petro-
1.3 This guide does not concern itself with the development
leum Products, Liquid Fuels, and Lubricants Testing
of test methods but rather with gathering the information
Laboratories
needed for a test method precision statement.
E177 Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
1.4 This guide is concerned with test methods which yield a
E178 Practice for Dealing With Outlying Observations
single numerical figure as the test result, although the single
E456 Terminology Relating to Quality and Statistics
figure may be the result of a calculation from a set of
E691 Practice for Conducting an Interlaboratory Study to
measurements.
Determine the Precision of a Test Method
1.5 This guide is designed for tests of properties that are
E1169 Practice for Conducting Ruggedness Tests
stable, such that bulk samples can be homogenized and
3
2.2 ISO/IEC Standards:
sub-samples can be prepared that will be identical and stable
ISO/IEC Guide 30 Terms and Definitions Used in Connec-
for the duration of the ILS testing period. This guide is not
tion with Reference Materials
designed for unstable properties or for properties that make it
ISO/IEC Guide 17025 General Requirements for the Com-
difficult to obtain stable, representative samples for an ILS
petence of Testing and Calibration Laboratories
conducted at multiple laboratory sites.
1.6 This guide represents the suggested practices for a
3. Terminology
typical precision study. Individual subcommittees may modify
3.1 Definitions:
this approach as their expertise directs.
1 2
This test method is under the jurisdiction of ASTM Committee D02 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Subcommittee D02.94 on Coordinating Subcommittee on Quality Assurance and Standards volume information, refer to the standard’s Document Summary page on
Statistics. the ASTM website.
3
Current edition approved April 1, 2015. Published May 2015. Originally Available from Available from Aerospace Industries Association of America,
approved in 2012. Last previous edition approved in 2012 as D7778 – 12. DOI: Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, http://
10.1520/D7778-15. www.aia-aerospace.org.
*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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D7778 − 15
3.1.1 accuracy, n—closeness of agreement between an in- 5.1.1 Qualitative tests such as Test
...

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: D7778 − 12 D7778 − 15 An American National Standard
Standard Guide for
Conducting an Interlaboratory Study to Determine the
1
Precision of a Test Method
This standard is issued under the fixed designation D7778; 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 Scope*
1.1 This guide describes the procedures for planning and conducting an interlaboratory study (ILS) of a test method used in
Petroleum Products and Lubricants Committee D02 of ASTM for the purpose of estimating repeatability and reproducibility of the
test method in accordance with ASTM Form and Style requirements.
1.2 This guide is concerned with the management of the ILS and intended to provide guidance for the planning stage and ensure
the process, logistics, and tools are identified and agreed upon in advance.
1.2.1 Selection of the samples and the impact of sample selection on the final scope of the test method—both the range of
materials covered in the scope and precision sections and the measurement range covered in the precision section—are important,
and careful consideration needs to be given to these aspects before an ILS is launched.
1.3 This guide does not concern itself with the development of test methods but rather with gathering the information needed
for a test method precision statement.
1.4 This guide is concerned with test methods which yield a single numerical figure as the test result, although the single figure
may be the result of a calculation from a set of measurements.
1.5 This guide is designed for tests of properties that are stable, such that bulk samples can be homogenized and sub-samples
can be prepared that will be identical and stable for the duration of the ILS testing period. This guide is not designed for unstable
properties or for properties that make it difficult to obtain stable, representative samples for an ILS conducted at multiple laboratory
sites.
1.6 This guide represents the suggested practices for a typical precision study. Individual subcommittees may modify this
approach as their expertise directs.
1.7 This guide is voluntary, and thus, is not required for an approved precision study.
2. Referenced Documents
2
2.1 ASTM Standards:
D130 Test Method for Corrosiveness to Copper from Petroleum Products by Copper Strip Test
D4306 Practice for Aviation Fuel Sample Containers for Tests Affected by Trace Contamination
D5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum Products
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
D6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purport
to Measure the Same Property of a Material
D6792 Practice for Quality System in Petroleum Products and Lubricants Testing Laboratories
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E178 Practice for Dealing With Outlying Observations
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1169 Practice for Conducting Ruggedness Tests
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.94.01 on Task Group A: Quality Assurance and Quality Control.
Current edition approved April 15, 2012April 1, 2015. Published June 2012May 2015. Originally approved in 2012. Last previous edition approved in 2012 as D7778 – 12.
DOI: 10.1520/D7778–12.10.1520/D7778-15.
2
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 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

---------------------- Page: 1 ----------------------
D7778 − 15
3
2.2 ISO/IEC Standards:
ISO/IEC Guide 30 Terms and Definitions Used in Connection with Reference Materials
ISO/IEC Guide 17025 General Requirements for the Competence of Testing and C
...