ASTM E2655-14
(Guide)Standard Guide for Reporting Uncertainty of Test Results and Use of the Term Measurement Uncertainty in ASTM Test Methods
Standard Guide for Reporting Uncertainty of Test Results and Use of the Term Measurement Uncertainty in ASTM Test Methods
SIGNIFICANCE AND USE
4.1 Part A of the “Blue Book,” Form and Style for ASTM Standards, introduces the statement of measurement uncertainty as an optional part of the report given for the result of applying a particular test method to a particular material.
4.2 Preparation of uncertainty estimates is a requirement for laboratory accreditation under ISO/IEC 17025. This guide describes some of the types of data that the laboratory can use as the basis for reporting uncertainty.
SCOPE
1.1 This guide provides concepts necessary for understanding the term “uncertainty” when applied to a quantitative test result. Several measures of uncertainty can be applied to a given measurement result; the interpretation of some of the common forms is described.
1.2 This guide describes methods for expressing test result uncertainty and relates these to standard statistical methodology. Relationships between uncertainty and concepts of precision and bias are described.
1.3 This guide also presents concepts needed for a laboratory to identify and characterize components of method performance. Elements that an ASTM method can include to provide guidance to the user on estimating uncertainty for the method are described.
1.4 The system of units for this guide is not specified. Dimensional quantities in the guide are presented only as illustrations of calculation methods and are not binding on products or test methods treated.
1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E2655 − 14 An American National Standard
Standard Guide for
Reporting Uncertainty of Test Results and Use of the Term
1
Measurement Uncertainty in ASTM Test Methods
This standard is issued under the fixed designation E2655; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This guide provides concepts necessary for understand-
E29Practice for Using Significant Digits in Test Data to
ing the term “uncertainty” when applied to a quantitative test
Determine Conformance with Specifications
result. Several measures of uncertainty can be applied to a
E122PracticeforCalculatingSampleSizetoEstimate,With
given measurement result; the interpretation of some of the
Specified Precision, the Average for a Characteristic of a
common forms is described.
Lot or Process
1.2 This guide describes methods for expressing test result
E177Practice for Use of the Terms Precision and Bias in
uncertainty and relates these to standard statistical methodol-
ASTM Test Methods
ogy. Relationships between uncertainty and concepts of preci-
E456Terminology Relating to Quality and Statistics
sion and bias are described.
E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.3 This guide also presents concepts needed for a labora-
E1402Guide for Sampling Design
tory to identify and characterize components of method per-
E2554Practice for Estimating and Monitoring the Uncer-
formance. Elements that an ASTM method can include to
tainty of Test Results of a Test Method Using Control
provide guidance to the user on estimating uncertainty for the
Chart Techniques
method are described.
E2586Practice for Calculating and Using Basic Statistics
1.4 The system of units for this guide is not specified.
2.2 Other Standard:
Dimensional quantities in the guide are presented only as
ISO/IEC 17025General Requirements for the Competence
3
illustrations of calculation methods and are not binding on
of Testing and Calibration Laboratories
products or test methods treated.
3. Terminology
1.5 This standard does not purport to address all of the
3.1 Definitions:
safety concerns, if any, associated with its use. It is the
3.1.1 AdditionalstatisticaltermsaredefinedinTerminology
responsibility of the user of this standard to establish appro-
E456.
priate safety, health, and environmental practices and deter-
3.1.2 accepted reference value, n—a value that serves as an
mine the applicability of regulatory limitations prior to use.
agreed-upon reference for comparison, and which is derived
1.6 This international standard was developed in accor-
as: (1) a theoretical or established value, based on scientific
dance with internationally recognized principles on standard-
principles, (2) an assigned or certified value, based on experi-
ization established in the Decision on Principles for the
mental work of some national or international organization, or
Development of International Standards, Guides and Recom-
(3) a consensus or certified value, based on collaborative
mendations issued by the World Trade Organization Technical
experimental work under the auspices of a scientific or
Barriers to Trade (TBT) Committee.
engineering group. E177
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1
This guide is under the jurisdiction of ASTM Committee E11 on Quality and contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Statistics and is the direct responsibility of Subcommittee E11.50 on Metrology. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Oct. 1, 2014. Published October 2014. Originally the ASTM website.
3
approved in 2008. Last previous edition approved in 2008 as E2655 – 08. DOI: Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/E2655-14. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E2655 − 14
3.1.3 error of result, n—a test result minus the accepted estimate the approximate magnitude of all these sources of
reference value of the characteristic. error.Incommoncasesthemeasurementwillbereportedinthe
form x 6 u, in which x represents the test result and u
3.1.4 expanded uncertainty, U, n—uncertainty reported as a
represents the uncertainty associated with x.
multiple of the standard uncertainty.
5.2 Practice E177 describes precision and bias. Uncer
...
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: E2655 − 08 E2655 − 14 An American National Standard
Standard Guide for
Reporting Uncertainty of Test Results and Use of the Term
1
Measurement Uncertainty in ASTM Test Methods
This standard is issued under the fixed designation E2655; 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 provides concepts necessary for understanding the term “uncertainty” when applied to a quantitative test result.
Several measures of uncertainty can be applied to a given measurement result; the interpretation of some of the common forms
is described.
1.2 This guide describes methods for expressing test result uncertainty and relates these to standard statistical methodology.
Relationships between uncertainty and concepts of precision and bias are described.
1.3 This guide also presents concepts needed for a laboratory to identify and characterize components of method performance.
Elements that an ASTM method can include to provide guidance to the user on estimating uncertainty for the method are described.
1.4 The system of units for this guide is not specified. Dimensional quantities in the guide are presented only as illustrations
of calculation methods and are not binding on products or test methods treated.
1.5 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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot or
Process
E141 Practice for Acceptance of Evidence Based on the Results of Probability Sampling
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
E1402 Guide for Sampling Design
E2554 Practice for Estimating and Monitoring the Uncertainty of Test Results of a Test Method Using Control Chart Techniques
E2586 Practice for Calculating and Using Basic Statistics
2.2 Other Standard:
3
ISOISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories
3. Terminology
3.1 Definitions:
3.1.1 Additional statistical terms are defined in Terminology E456.
3.1.2 accepted reference value, n—a value that serves as an agreed-upon reference for comparison, and which is derived as: (1)
a theoretical or established value, based on scientific principles, (2) an assigned or certified value, based on experimental work of
1
This guide is under the jurisdiction of ASTM Committee E11 on Quality and Statistics and is the direct responsibility of Subcommittee E11.20 on Test Method Evaluation
and Quality Control.
Current edition approved Oct. 1, 2008Oct. 1, 2014. Published November 2008October 2014. Originally approved in 2008. Last previous edition approved in 2008 as E2655
– 08. DOI: 10.1520/E2655-08. 10.1520/E2655-14.
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.
3
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E2655 − 14
some national or international organization, or (3) a consensus or certified value, based on collaborative experimental work under
the auspices of a scientific or engineering group. E177
3.1.3 error of result, n—a test result minus the accepted reference value of the characteristic.
3.1.4 expanded uncertainty, U, n—uncertainty reported as a multiple of the standard uncertainty.
3.1.5 random error of result, n—a component of the error that, in the course of a number of test results for the same
characteristic, varies in an un
...
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