iTeh StandardsiTeh Standards
EURUSD
Your shopping cart is empty.
ASTM

ASTM E691-23

(Practice)

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

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

ABSTRACT
This practice describes the techniques for planning, conducting, analyzing, and treating the results of an interlaboratory study (ILS) of a test method. The statistical techniques described in this practice provide adequate information for formulating the precision statement of a test method. This practice is also concerned exclusively with test methods which yield a single numerical figure as the test result, although the single figure may be the outcome of a calculation from a set of measurements. ASTM regulations require precision statements in all test methods in terms of repeatability and reproducibility and knowledge of the test method precision is useful in commerce and in technical work when comparing test results against standard values or between data sources.
SIGNIFICANCE AND USE
4.1 ASTM regulations require precision statements in all test methods in terms of repeatability and reproducibility. This practice may be used in obtaining the needed information as simply as possible. This information may then be used to prepare a precision statement in accordance with Practice E177. Knowledge of the test method precision is useful in commerce and in technical work when comparing test results against standard values (such as specification limits) or between data sources (different laboratories, instruments, etc.).  
4.1.1 When a test method is applied to a large number of portions of a material that are as nearly alike as possible, the test results obtained will not all have the same value. A measure of the degree of agreement among these test results describes the precision of the test method for that material. Numerical measures of the variability between such test results provide inverse measures of the precision of the test method. Greater variability implies smaller (that is, poorer) precision and larger imprecision.  
4.1.2 Precision is reported as a standard deviation, coefficient of variation (relative standard deviation), variance, or a precision limit (a data range indicating no statistically significant difference between test results).  
4.1.3 This practice is designed only to estimate the precision of a test method. However, when accepted reference values are available for the property levels, the test result data obtained according to this practice may be used in estimating the bias of the test method. For a discussion of bias estimation and the relationships between precision, bias, and accuracy, see Practice E177.  
4.2 The procedures presented in this practice consist of three basic steps: planning the interlaboratory study, guiding the testing phase of the study, and analyzing the test result data.  
4.2.1 The planning phase includes forming the ILS task group, the study design, selection, and number of participating laborato...
SCOPE
1.1 This practice describes the techniques for planning, conducting, analyzing, and treating the results of an interlaboratory study (ILS) of a test method. The statistical techniques described in this practice provide adequate information for formulating the precision statement of a test method.  
1.2 This practice does not concern itself with the development of test methods but rather with gathering the information needed for a test method precision statement after the development stage has been successfully completed. The data obtained in the interlaboratory study may indicate, however, that further effort is needed to improve the test method.  
1.3 Since the primary purpose of this practice is the development of the information needed for a precision statement, the experimental design in this practice may not be optimum for evaluating materials, apparatus, or individual laboratories.  
1.4 Field of Application—This practice is concerned exclusively with test methods which yield a single numerical figure as the test result, although the single figure may be the outcome of a calculation from a set of measurements.  
1.4.1 This practice ...

General Information

Status
Published
Publication Date
31-Mar-2023
ICS
19.020 - Test conditions and procedures in general
Technical Committee
E11 - Quality and Statistics
Drafting Committee
E11.20 - Test Method Evaluation and Quality Control
Current Stage
Ref Project

Buy Standard

ASTM E691-23 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodASTM E691-23 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
PreviousNext
Standard
ASTM E691-23 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
English language
23 pages
sale 15% off
Preview
sale 15% off
Preview
REDLINE ASTM E691-23 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodREDLINE ASTM E691-23 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
PreviousNext
Standard
REDLINE ASTM E691-23 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
English language
23 pages
sale 15% off
Preview
sale 15% off
Preview

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: E691 − 23 An American National Standard
Standard Practice for
Conducting an Interlaboratory Study to Determine the
1
Precision of a Test Method
This standard is issued under the fixed designation E691; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope 1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
1.1 This practice describes the techniques for planning,
ization established in the Decision on Principles for the
conducting, analyzing, and treating the results of an interlabo-
Development of International Standards, Guides and Recom-
ratory study (ILS) of a test method. The statistical techniques
mendations issued by the World Trade Organization Technical
described in this practice provide adequate information for
Barriers to Trade (TBT) Committee.
formulating the precision statement of a test method.
1.2 This practice does not concern itself with the develop- 2. Referenced Documents
ment of test methods but rather with gathering the information 2
2.1 ASTM Standards:
needed for a test method precision statement after the devel-
E29 Practice for Using Significant Digits in Test Data to
opment stage has been successfully completed. The data
Determine Conformance with Specifications
obtained in the interlaboratory study may indicate, however,
E177 Practice for Use of the Terms Precision and Bias in
that further effort is needed to improve the test method.
ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
1.3 Since the primary purpose of this practice is the devel-
opment of the information needed for a precision statement, the E1169 Practice for Conducting Ruggedness Tests
E1402 Guide for Sampling Design
experimental design in this practice may not be optimum for
evaluating materials, apparatus, or individual laboratories. E2282 Guide for Defining the Test Result of a Test Method
1.4 Field of Application—This practice is concerned exclu-
3. Terminology
sively with test methods which yield a single numerical figure
3.1 Definitions—Unless otherwise noted in this standard, all
as the test result, although the single figure may be the outcome
terms relating to quality and statistics are defined in E456.
of a calculation from a set of measurements.
3.1.1 accuracy, n—the closeness of agreement between a
1.4.1 This practice does not cover methods in which the
test result and an accepted reference value. E177
measurement is a categorization; however, for many practical
3.1.2 bias, n—the difference between the expectation of the
purposes categorical outcomes can be scored, such as zero-one
test results and an accepted reference value. E177
scoring for binary measurements or as integers, ranks for
example, for well-ordered categories and then the test result
3.1.3 interlaboratory study, (ILS) in ASTM, n—a designed
can be defined as an average, or other summary statistic, of
procedure for obtaining a precision statement for a test method,
several individual scores.
involving multiple laboratories, each generating replicate test
results on one or more materials.
1.5 This standard may involve hazardous materials,
operations, and equipment. This standard does not purport to
3.1.4 observation, n—the process of obtaining information
address all of the safety concerns, if any, associated with its
regarding the presence or absence of an attribute of a test
use. It is the responsibility of the user of this standard to
specimen, or of making a reading on a characteristic or
establish appropriate safety, health, and environmental prac-
dimension of a test specimen. E2282
tices and determine the applicability of regulatory limitations
3.1.5 precision, n—the closeness of agreements between
prior to use.
independent test results obtained under stipulated conditions.
E177
1
This practice is under the jurisdiction of ASTM Committee E11 on Quality and
Statistics and is the direct responsibility of Subcommittee E11.20 on Test Method
2
Evaluation and Quality Control. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2023. Published April 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1979. Last previous edition approved in 2022 as E691 – 22. DOI: Standards volume information, refer
...

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: E691 − 22 E691 − 23 An American National Standard
Standard Practice for
Conducting an Interlaboratory Study to Determine the
1
Precision of a Test Method
This standard is issued under the fixed designation E691; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope
1.1 This practice describes the techniques for planning, conducting, analyzing, and treating the results of an interlaboratory study
(ILS) of a test method. The statistical techniques described in this practice provide adequate information for formulating the
precision statement of a test method.
1.2 This practice does not concern itself with the development of test methods but rather with gathering the information needed
for a test method precision statement after the development stage has been successfully completed. The data obtained in the
interlaboratory study may indicate, however, that further effort is needed to improve the test method.
1.3 Since the primary purpose of this practice is the development of the information needed for a precision statement, the
experimental design in this practice may not be optimum for evaluating materials, apparatus, or individual laboratories.
1.4 Field of Application—This practice is concerned exclusively with test methods which yield a single numerical figure as the
test result, although the single figure may be the outcome of a calculation from a set of measurements.
1.4.1 This practice does not cover methods in which the measurement is a categorization; however, for many practical purposes
categorical outcomes can be scored, such as zero-one scoring for binary measurements or as integers, ranks for example, for
well-ordered categories and then the test result can be defined as an average, or other summary statistic, of several individual
scores.
1.5 This standard may involve hazardous materials, operations, and equipment. 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 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:
1
This practice 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 May 15, 2022April 1, 2023. Published June 2022April 2023. Originally approved in 1979. Last previous edition approved in 20212022 as
E691 – 21.E691 – 22. DOI: 10.1520/E0691-22.10.1520/E0691-23.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E691 − 23
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E456 Terminology Relating to Quality and Statistics
E1169 Practice for Conducting Ruggedness Tests
E1402 Guide for Sampling Design
E2282 Guide for Defining the Test Result of a Test Method
3. Terminology
3.1 Definitions—Terminology—Unless E456 provides a more extensive list of terms in E11 standards.otherwise noted in this
standard, all terms relating to quality and statistics are defined in E456.
3.1.1 accuracy, n—the closeness of agreement between a test result and an accepted reference value. E177
3.1.2 bias, n—the difference between the expectation of the test results and an accepted reference value. E177
3.1.3 interlaboratory study, (ILS) in ASTM, n—a
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.

This May Also Interest You

ASTM
ASTM E1488-12(2023)(Guide)
Standard Guide for Statistical Procedures to Use in Developing and Applying Test Methods

ABSTRACT
This guide identifies statistical procedures for use in developing new test methods or revising or evaluating existing test methods, or both. It also cites statistical procedures especially useful in the application of test methods. This standard recommends what approaches may be taken and indicates which standards may be used to perform such assessments.
SIGNIFICANCE AND USE
4.1 The creation of a standardized test method generally follows a series of steps from inception to approval and ongoing use. In all such stages there are questions of how well the test method performs.  
4.1.1 Assessments of a new or existing test method generally involve statistical planning and analysis. This standard recommends what approaches may be taken and indicates which standards may be used to perform such assessments.  
4.2 This standard introduces a series of phases which are recommended to be considered during the life cycle of a test method as depicted in Fig. 1. These begin with a design phase where the standard is initially prepared. A development phase involves a variety of experiments that allow further refinement and understanding of how the test method performs within a laboratory. In an evaluation phase the test method is then examined by way of interlaboratory studies resulting in precision and bias statistics which are published in the standard. Finally, the test method is subject to a monitoring phase.
FIG. 1 Sequence of Steps  
4.3 All ASTM test methods are required to include statements on precision and bias.3  
4.4 Since ASTM began to require all test methods to have precision and bias statements that are based on interlaboratory test methods, there has been increased concern regarding what statistical experiments and procedures to use during the development of the test methods. Although there exists a wide range of statistical procedures, there is a small group of generally accepted techniques that are beneficial to follow. This guide is designed to provide a brief overview of these procedures and to suggest an appropriate sequence of carrying out these procedures.  
4.5 Statistical procedures often result in interpretations that are not absolutes. Sometimes the information obtained may be inadequate or incomplete, which may lead to additional questions and the need for further experimentation. Information outside the data is al...
SCOPE
1.1 This guide identifies statistical procedures for use in developing new test methods or revising or evaluating existing test methods, or both.  
1.2 This guide also cites statistical procedures especially useful in the application of test methods.  
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.

  • Guide
    9 pages
    English language
    sale 15% off
ASTM
ASTM E2282-14(2023)(Guide)
Standard Guide for Defining the Test Result of a Test Method

ABSTRACT
The purpose of this guide is to provide guidelines for identifying the elements that comprise the test result of a test method and to illustrate how these elements combine into the test result. It covers the types of measurement scales used for expressing observations and test results. This guide provides information on the construction of test results from more elemental measurements.
SIGNIFICANCE AND USE
4.1 All test methods have an output in the form of a test result. This guide provides information on the construction of test results from more elemental measurements.  
4.2 A well defined test result is necessary before any precision statements can be made about the test method.  
4.2.1 Form and Style for ASTM Standards,2 Section A21, requires that every test method shall contain a statement regarding its precision, preferably as a result of an interlaboratory test program. Reporting of such studies is described in Practice E177, which illustrates the development of test results from observations and test determinations.  
4.2.2 Precision statements for ASTM test methods are applicable to test results. They are not applicable to test determinations or observations, unless specifically and clearly indicated otherwise.
SCOPE
1.1 The purpose of this guide is to provide guidelines for identifying the elements that comprise the test result of a test method and to illustrate how these elements combine into the test result.  
1.2 Types of measurement scales used for expressing observations and test results are discussed.  
1.3 No system of units is specified in this standard.  
1.4 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.

  • Guide
    4 pages
    English language
    sale 15% off
ASTM
ASTM E29-22(Practice)
Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

ABSTRACT
This practice is intended to assist the various technical committees in the use of uniform methods of indicating the number of digits which are to be considered significant in specification limits, for example, specified maximum values and specified minimum values. This practice is also intended to be used in determining conformance with specifications when the applicable ASTM specifications or standards make a direct reference.
SCOPE
1.1 This practice is intended to assist the various technical committees in the use of uniform methods of indicating the number of digits which are to be considered significant in specification limits, for example, specified maximum values and specified minimum values. Its aim is to outline methods which should aid in clarifying the intended meaning of specification limits with which observed values or calculated test results are compared in determining conformance with specifications.  
1.2 This practice is intended to be used in determining conformance with specifications when the applicable ASTM specifications or standards make direct reference to this practice.  
1.3 Reference to this practice is valid only when a choice of method has been indicated, that is, either absolute method or rounding method.  
1.4 The system of units for this practice is not specified. Dimensional quantities in the practice are presented only as illustrations of calculation methods. The examples 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.6 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.

  • Standard
    5 pages
    English language
    sale 15% off
  • Standard
    5 pages
    English language
    sale 15% off
ASTM
ASTM E1325-21(Terminology)
Standard Terminology Relating to Design of Experiments

ABSTRACT
This standard includes those statistical items related to the area of design of experiments for which standard definitions appear desirable. It provides definitions, descriptions, discussion, and comparison of terms.
SIGNIFICANCE AND USE
3.1 This standard is a subsidiary to Terminology E456.  
3.2 It provides definitions, descriptions, discussion, and comparison of terms.
SCOPE
1.1 This standard includes those statistical items related to the area of design of experiments for which standard definitions appear desirable.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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.

  • Standard
    8 pages
    English language
    sale 15% off
  • Standard
    8 pages
    English language
    sale 15% off
ASTM
ASTM E1169-21(Practice)
Standard Practice for Conducting Ruggedness Tests

SIGNIFICANCE AND USE
4.1 A ruggedness test is a special application of a statistically designed experiment that makes changes in the test method variables, called factors, and then calculates the subsequent effect of those changes upon the test results. Factors are features of the test method or of the laboratory environment that are known to vary across laboratories and are subject to control by the test method.  
4.1.1 Statistical design enables more efficient and cost-effective determination of the factor effects than would be achieved if separate experiments were carried out for each factor. The proposed designs are easy to use in developing the information needed for evaluating quantitative test methods.  
4.2 In ruggedness testing, the two levels (settings) for each factor are chosen to use moderate separations between the high and low settings. In general, if there is an underlying difference between the levels, then the size of effects will increase with increased separation between the high and low settings of the factors. A run is an execution of the test method under prescribed settings of each of the factors under study. A ruggedness test consists of a set of runs.  
4.3 A ruggedness test is usually conducted within a single laboratory on uniform material, so that the effects of changing only the factors are measured. The results may then be used to assist in determining the degree of control required of factors described in the test method.  
4.4 Ruggedness testing should precede an interlaboratory (round robin) study to correct any deficiencies in the test method and may also be part of the validation phase of developing a standard test method as described in Guide E1488.  
4.5 This standard discusses design and analysis of ruggedness testing in Section 5 and contains an example of a basic eight run design. Some caution must be used in interpretation of results, since interaction effects may be present. These effects are present when a factor effect changes with the ...
SCOPE
1.1 This practice covers conducting ruggedness tests. The purpose of a ruggedness test is to identify those factors that strongly influence the measurements provided by a specific test method and to estimate how closely those factors need to be controlled.  
1.2 This practice restricts itself to experimental designs with two levels per factor. The designs require the simultaneous change of the levels of all of the factors, thus permitting the determination of the effects of each of the factors on the measured results.  
1.3 The system of units for this practice is not specified. Dimensional quantities in the practice are presented only as illustrations of calculation methods. The examples are not binding on products or test methods treated.  
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 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.

  • Standard
    17 pages
    English language
    sale 15% off
  • Standard
    17 pages
    English language
    sale 15% off
ASTM
ASTM E3264-21(Guide)
Standard Guide for Homogeneity of Samples and Reference Materials Used for Inter- and Intra-Laboratory Studies

SIGNIFICANCE AND USE
5.1 This guide presents techniques and guidance for evaluating and assuring homogeneity of individual samples or bulk materials and can be used for either interlaboratory or intra-laboratory studies. The types of studies include, but are not limited to, studies to determine precision estimates for test methods, proficiency testing programs, and studies related to quality control of testing within a single laboratory.  
5.2 Because the test results of any laboratory study are affected by the quality of the samples tested, producing homogeneous samples and determining the degree of homogeneity is important for interpreting the results of the study.  
5.3 Five techniques are presented in this guide to evaluate sample homogeneity for a range of circumstances and degrees of rigor. The circumstances under which the studies are conducted and the degree of rigor required may differ. The user should consider the circumstances listed in each technique to determine which is appropriate for the study at hand.  
5.4 Each of the Techniques 1, 2, and 3 provides a procedure for testing and evaluating sample homogeneity when replicate testing of the samples is possible. Technique 4 provides a plan to evaluate sample homogeneity when replicate testing is not possible. Technique 5 recommends practices for producing homogeneous samples for circumstances when homogeneity testing is not possible.  
5.5 When the conditions of adequate within-sample homogeneity and between-sample homogeneity are satisfied, any differences in test results on multiple samples can reasonably be attributed to testing variation and not due to sample variation.  
5.6 When differences within or between samples are discovered and the samples are deemed insufficiently homogeneous, the sample preparation process can be improved or corrected and a new set of samples can be prepared. Or, in cases where the sample homogeneity cannot be improved or for other reasons when the samples must be used, the method of eval...
SCOPE
1.1 This guide presents techniques and guidance for evaluating and assuring homogeneity of individual samples and bulk materials used for interlaboratory and intra-laboratory studies.  
1.2 This guide is applicable to samples and reference materials used for proficiency testing programs and for interlaboratory studies to determine precision estimates for test methods. It may also be useful for activities related to quality control of testing within a single laboratory.  
1.3 Five techniques are presented for assessing sample homogeneity. The five techniques are not an exhaustive list of available techniques for assessing homogeneity of samples, but the techniques were chosen to cover a range of circumstances (and various degrees of rigor required) for laboratory studies of various types and purposes.  
1.4 Each of the first four techniques provides a scheme for testing for homogeneity and a statistical procedure for evaluating the results of the homogeneity testing. The circumstances are described for which each of the techniques is suited.  
1.5 For circumstances when homogeneity testing is not possible, the fifth technique provides guidance for producing homogeneous samples.  
1.6 The appendixes of this guide provide example spreadsheets for Techniques 1, 2, 3, and 4.  
1.7 This guide is not intended for evaluation of certified reference materials (CRMs) or materials used for calibration.  
1.8 Units—The system of units for this standard is not specified. Dimensional quantities in the standard are presented only as illustrations of calculation methods. The examples are not binding on products or test methods treated.  
1.9 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, health, and environmental practices and determine the applicability of regulatory limitations prior to ...

  • Guide
    32 pages
    English language
    sale 15% off
ASTM
ASTM E177-20(Practice)
Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods

ABSTRACT
The purpose of this practice is to present concepts necessary to the understanding of the terms “precision” and “bias” as used in quantitative test methods. This practice also describes methods of expressing precision and bias and, in a final section, gives examples of how statements on precision and bias may be written for ASTM test methods. A statement of precision allows potential users of a test method to assess in general terms the test method’s usefulness with respect to variability in proposed applications.
SIGNIFICANCE AND USE
4.1 Part A of the “Blue Book,” Form and Style for ASTM Standards, requires that all test methods include statements of precision and bias. This practice discusses these two concepts and provides guidance for their use in statements about test methods.  
4.2 Precision—A statement of precision allows potential users of a test method to assess in general terms the test method’s usefulness with respect to variability in proposed applications. A statement of precision is not intended to exhibit values that can be exactly duplicated in every user’s laboratory. Instead, the statement provides guidelines as to the magnitude of variability that can be expected between test results when the method is used in one, or in two or more, reasonably competent laboratories. For a discussion of precision, see 8.1.  
4.3 Bias—A statement of bias furnishes guidelines on the relationship between a set of typical test results produced by the test method under specific test conditions and a related set of accepted reference values (see 9.1).  
4.3.1 An alternative term for bias is trueness, which has a positive connotation, in that greater bias is associated with less favorable trueness. Trueness is the systematic component of accuracy.  
4.4 Accuracy—The term “accuracy,” used in earlier editions of Practice E177, embraces both precision and bias (see 9.3).
SCOPE
1.1 The purpose of this practice is to present concepts necessary to the understanding of the terms “precision” and “bias” as used in quantitative test methods. This practice also describes methods of expressing precision and bias and, in a final section, gives examples of how statements on precision and bias may be written for ASTM test methods.  
1.2 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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.

  • Standard
    10 pages
    English language
    sale 15% off
  • Standard
    10 pages
    English language
    sale 15% off
ASTM
ASTM G136-03(2023)e1(Practice)
Standard Practice for Determination of Soluble Residual Contaminants in Materials by Ultrasonic Extraction

SIGNIFICANCE AND USE
5.1 This practice is suitable for the determination of extractable substances that may be found in materials used in systems or components requiring a high level of cleanliness, such as oxygen systems. Soft goods, such as seals and valve seats, may be tested as received. Gloves and wipes, or samples thereof, to be used in cleaning operations may be evaluated prior to use to ensure that the proposed extracting agent does not extract or deposit chemicals, or both, on the surface to be cleaned.  
5.2 Wipes or other cleaning equipment may be tested after use to determine the amount of contaminant removed from a surface.
Note 1: The amount of material extracted may be dependent upon the frequency and power density of the ultrasonic unit.  
5.3 The extraction efficiency has been shown to vary with the frequency and power density of the ultrasonic unit. The unit, therefore, must be carefully evaluated to optimize the extraction conditions.
SCOPE
1.1 This practice may be used to extract nonvolatile and semivolatile residues from materials such as new and used gloves, new and used wipes, component soft goods, and so forth. When used with proposed cleaning materials (wipes, gloves, and so forth), this practice may be used to determine the potential of the proposed solvent or other fluids to extract contaminants (plasticizers, residual detergents, brighteners, and so forth) and deposit them on the surface being cleaned.  
1.2 This practice is not suitable for the evaluation of particulate contamination.  
1.3 The values stated in SI units are to be regarded standard. No other units of measurement are included in this standard.  
1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 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.

  • Standard
    6 pages
    English language
    sale 15% off
ASTM
ASTM D6259-23(Practice)
Standard Practice for Determination of a Pooled Limit of Quantitation for a Test Method

SIGNIFICANCE AND USE
5.1 Background—In a single laboratory, the limit of quantitation, LOQ, equal to ten times the standard deviation obtained under repeatability conditions extrapolated to zero concentration (s0) based on samples with close to zero concentrations has been recommended.3 A test result at this LOQ has an uncertainty of ±30 % at the 99 % confidence level.  
5.1.1 This practice uses a regression technique to determine a similar limit for a test method (PLOQ) using statistically pooled repeatability standard deviations over multiple operators/laboratories/samples from ILS data. This PLOQ can be used by industry to assess the reliability of a test method, or, compare reliability of different test methods, for quantitative measurement at concentrations near zero. Similarly, quantitative test results obtained using the test method for levels at or below the PLOQ can be expected by industry to have an uncertainty of ±30 % or greater at the 95 % confidence level.  
5.1.2 The regression technique described in this practice can also be used to determine a limit of quantitation specific for a single laboratory (LLOQ). The limit thus quantified for one laboratory is defined by this standard as the laboratory limit of quantitation (LLOQ).  
5.1.3 It should be noted that since differences in repeatability testing capabilities between different laboratories can exist, therefore, LLOQ determined at a single laboratory can be different than the PLOQ determined for the test method.  
5.2 Values below the PLOQ are deemed by this practice to be too uncertain for meaningful use in commerce, or in regulatory activities.
SCOPE
1.1 This practice covers the use of standard regression techniques and data from an interlaboratory study to determine a lower quantitative limit for a test method. This determined lower limit represents the numerical limit at or above which the test results are considered to be quantitatively meaningful for commerce or regulatory activities by this practice. It is defined by this standard as the pooled limit of quantitation (PLOQ) for the test method.  
1.2 This practice is applicable to test methods that are capable of producing numerical test results close to zero. Examples are those test methods that determine quantitatively the concentration of analyte(s) near zero.  
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.

  • Standard
    4 pages
    English language
    sale 15% off
  • Standard
    4 pages
    English language
    sale 15% off
ASTM
ASTM E2282-14(2023)(Guide)
Standard Guide for Defining the Test Result of a Test Method

ABSTRACT
The purpose of this guide is to provide guidelines for identifying the elements that comprise the test result of a test method and to illustrate how these elements combine into the test result. It covers the types of measurement scales used for expressing observations and test results. This guide provides information on the construction of test results from more elemental measurements.
SIGNIFICANCE AND USE
4.1 All test methods have an output in the form of a test result. This guide provides information on the construction of test results from more elemental measurements.  
4.2 A well defined test result is necessary before any precision statements can be made about the test method.  
4.2.1 Form and Style for ASTM Standards,2 Section A21, requires that every test method shall contain a statement regarding its precision, preferably as a result of an interlaboratory test program. Reporting of such studies is described in Practice E177, which illustrates the development of test results from observations and test determinations.  
4.2.2 Precision statements for ASTM test methods are applicable to test results. They are not applicable to test determinations or observations, unless specifically and clearly indicated otherwise.
SCOPE
1.1 The purpose of this guide is to provide guidelines for identifying the elements that comprise the test result of a test method and to illustrate how these elements combine into the test result.  
1.2 Types of measurement scales used for expressing observations and test results are discussed.  
1.3 No system of units is specified in this standard.  
1.4 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.

  • Guide
    4 pages
    English language
    sale 15% off