ASTM E1950-17

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: E1950 − 10 E1950 − 17
Standard Practice for
1
Reporting Results from Methods of Chemical Analysis
This standard is issued under the fixed designation E1950; 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 practice covers the approximate number of digits required to express the expected precision of results reported from
standard methods of chemical analysis. This practice provides selection criteria and proper form and symbols for coding results
when necessary to indicate the relative reliability of results having small values.
1.2 Specifically excluded is consideration of report forms and the associated informational content of reports in which results
are tabulated or transmitted. It is assumed that the reporting laboratory has established a report format to ensure proper
identification of the materials tested, the nature and conditions of the test, the responsible personnel, and other related information
in accordance with existing regulations and good laboratory practices.
1.3 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:
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
E1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method
E1763 Guide for Interpretation and Use of Results from Interlaboratory Testing of Chemical Analysis Methods (Withdrawn
3
2015)
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms, refer to Terminology E135.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 lower limit, L, n—the lower limit of the quantitative analyte mass fraction or concentration range (see Annex A1).
3.2.2 low-level reproducibility index, K , n—the reproducibility index constant (for low analyte levels) determined in
R
accordance withas directed by Guide E1763.
3.2.3 null limit, NL, n—the analyte content below which results are so near zero that averaging is unlikely to yield a value
significantly different from zero.
3.2.4 quantitative, adj—relating to results, having a numerical value that includes at least one significant digit (see Practice
E29).
4. Significance and Use
4.1 A result must be stated to a sufficient number of digits so that a user receives both quantitative information and a measure
of the variability of the value reported.
1
This practice is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
Subcommittee E01.22 on Laboratory Quality.
Current edition approved Oct. 1, 2010Nov. 15, 2017. Published December 2010 December 2017. Originally approved in 1998. Last previous edition approved in 20032010
as E1950 – 98 (2003).E1950 – 10. DOI: 10.1520/E1950-10.10.1520/E1950-17.
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
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E1950 − 17
4.2 The range of application of most methods of chemical analysis is based upon the presumption that the quantitative results
produced are to be used to compare the analyte content of the test material with specified limiting values. However, analytical
results may be used legitimately for other purposes. If the same material is analyzed a number of times or a product is analyzed
periodically during an interval of production, each set of results may be averaged to yield an average result having improved
reliability, provided nothing has been done between analyses to modify the composition of the analyzed materia
...

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: E1950 − 17
Standard Practice for
1
Reporting Results from Methods of Chemical Analysis
This standard is issued under the fixed designation E1950; 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 Interlaboratory Testing of Chemical Analysis Methods
3
(Withdrawn 2015)
1.1 This practice covers the approximate number of digits
required to express the expected precision of results reported
3. Terminology
from standard methods of chemical analysis. This practice
3.1 Definitions:
provides selection criteria and proper form and symbols for
3.1.1 For definitions of terms, refer to Terminology E135.
coding results when necessary to indicate the relative reliability
3.2 Definitions of Terms Specific to This Standard:
of results having small values.
3.2.1 lower limit, L, n—the lower limit of the quantitative
1.2 Specifically excluded is consideration of report forms
analyte mass fraction or concentration range (see Annex A1).
and the associated informational content of reports in which
3.2.2 low-level reproducibility index, K , n—the reproduc-
R
results are tabulated or transmitted. It is assumed that the
ibility index constant (for low analyte levels) determined as
reporting laboratory has established a report format to ensure
directed by Guide E1763.
proper identification of the materials tested, the nature and
3.2.3 null limit, NL, n—the analyte content below which
conditions of the test, the responsible personnel, and other
results are so near zero that averaging is unlikely to yield a
related information in accordance with existing regulations and
value significantly different from zero.
good laboratory practices.
3.2.4 quantitative, adj—relating to results, having a numeri-
1.3 This international standard was developed in accor-
cal value that includes at least one significant digit (see Practice
dance with internationally recognized principles on standard-
E29).
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4. Significance and Use
mendations issued by the World Trade Organization Technical
4.1 A result must be stated to a sufficient number of digits so
Barriers to Trade (TBT) Committee.
that a user receives both quantitative information and a
measure of the variability of the value reported.
2. Referenced Documents
2
4.2 The range of application of most methods of chemical
2.1 ASTM Standards:
analysis is based upon the presumption that the quantitative
E29 Practice for Using Significant Digits in Test Data to
results produced are to be used to compare the analyte content
Determine Conformance with Specifications
of the test material with specified limiting values. However,
E135 Terminology Relating to Analytical Chemistry for
analytical results may be used legitimately for other purposes.
Metals, Ores, and Related Materials
If the same material is analyzed a number of times or a product
E1601 Practice for Conducting an Interlaboratory Study to
is analyzed periodically during an interval of production, each
Evaluate the Performance of an Analytical Method
set of results may be averaged to yield an average result having
E1763 Guide for Interpretation and Use of Results from
improved reliability, provided nothing has been done between
analyses to modify the composition of the analyzed material.
1
This practice is under the jurisdiction of ASTM Committee E01 on Analytical
Results that fall below the lower limit, although not quantita-
Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
tive individually, contain compositional information and may
Subcommittee E01.22 on Laboratory Quality.
be reported. The reporting system in this practice permits the
Current edition approved Nov. 15, 2017. Published December 2017. Originally
approved in 1998. Last previous edition approved in 2010 as E1950 – 10. DOI: analyst to indicate which values are likely to be rendered
10.1520/E1950-17.
quantitative by averaging and which are not.
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
3
Standards volume information, refer to the standard’s Document Summary page on
The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E1950 − 17
4.3 The system is simple enough to be used routinely in
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