iTeh StandardsiTeh Standards
EURUSD
Your shopping cart is empty.
ASTM

ASTM E2164-16

(Test Method)

Standard Test Method for Directional Difference Test

Standard Test Method for Directional Difference Test

SIGNIFICANCE AND USE
5.1 The directional difference test determines with a given confidence level whether or not there is a perceivable difference in the intensity of a specified attribute between two samples, for example, when a change is made in an ingredient, a process, packaging, handling, or storage.  
5.2 The directional difference test is inappropriate when evaluating products with sensory characteristics that are not easily specified, not commonly understood, or not known in advance. Other difference test methods such as the same-different test should be used.  
5.3 A result of no significant difference in a specific attribute does not ensure that there are no differences between the two samples in other attributes or characteristics, nor does it indicate that the attribute is the same for both samples. It may merely indicate that the degree of difference is too low to be detected with the sensitivity (α, β, and Pmax) chosen for the test.  
5.3.1 The method itself does not change whether the purpose of the test is to determine that two samples are perceivably different versus that the samples are not perceivably different. Only the selected values of Pmax, α, and β change. If the objective of the test is to determine if the two samples are perceivably different, then the value selected for α is typically smaller than the value selected for β. If the objective is to determine if no perceivable difference exists, then the value selected for β is typically smaller than the value selected for α and the value of Pmax needs to be stated explicitly.
SCOPE
1.1 This test method covers a procedure for comparing two products using a two-alternative forced-choice task.  
1.2 This method is sometimes referred to as a paired comparison test or as a 2-AFC (alternative forced choice) test.  
1.3 A directional difference test determines whether a difference exists in the perceived intensity of a specified sensory attribute between two samples.  
1.4 Directional difference testing is limited in its application to a specified sensory attribute and does not directly determine the magnitude of the difference for that specific attribute. Assessors must be able to recognize and understand the specified attribute. A lack of difference in the specified attribute does not imply that no overall difference exists.  
1.5 This test method does not address preference.  
1.6 A directional difference test is a simple task for assessors, and is used when sensory fatigue or carryover is a concern. The directional difference test does not exhibit the same level of fatigue, carryover, or adaptation as multiple sample tests such as triangle or duo-trio tests. For detail on comparisons among the various difference tests, see Ennis (1), MacRae (2), and O'Mahony and Odbert (3).2  
1.7 The procedure of the test described in this document consists of presenting a single pair of samples to the assessors.  
1.8 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.

General Information

Status
Published
Publication Date
30-Sep-2016
ICS
19.020 - Test conditions and procedures in general
Technical Committee
E18 - Sensory Evaluation
Drafting Committee
E18.04 - Fundamentals of Sensory
Current Stage
Ref Project

Relations

Refers
ASTM E456-13A(2017)e3 - Standard Terminology Relating to Quality and Statistics
Effective Date
01-Oct-2017
Refers
ASTM E1871-17 - Standard Guide for Serving Protocol for Sensory Evaluation of Foods and Beverages
Effective Date
01-Sep-2017
Refers
ASTM E253-16 - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
01-Jun-2016
Refers
ASTM E253-15 - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
15-Jan-2015
Refers
ASTM E253-15a - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
01-Jun-2015
Refers
ASTM E253-18a - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
01-Oct-2018
Refers
ASTM E253-19 - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
15-Oct-2019
Refers
ASTM E456-13A(2017)e1 - Standard Terminology Relating to Quality and Statistics
Effective Date
01-Oct-2017
Refers
ASTM E253-17 - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
01-May-2017
Refers
ASTM E253-18 - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
15-Jun-2018
Refers
ASTM E253-15b - Standard Terminology Relating to Sensory Evaluation of Materials and Products
Effective Date
01-Dec-2015
Referred By
ASTM D5237-14(2019) - Standard Guide for Evaluating Fabric Softeners
Effective Date
01-Oct-2016
Referred By
ASTM E3093-20 - Standard Guide for Structured Small Group Product Evaluations
Effective Date
01-Oct-2016
Referred By
ASTM E460-21 - Standard Practice for Determining Effect of Packaging on Food and Beverage Products During Storage
Effective Date
01-Oct-2016
Referred By
ASTM E1958-22 - Standard Guide for Sensory Claim Substantiation
Effective Date
01-Oct-2016
Referred By
ASTM E2263-12(2018) - Standard Test Method for Paired Preference Test
Effective Date
01-Oct-2016
Referred By
ASTM E3261-21 - Standard Guide for Odor Evaluation of Products and Materials Under Controlled Conditions With Trained Panel
Effective Date
01-Oct-2016

Buy Standard

ASTM E2164-16 - Standard Test Method for Directional Difference TestASTM E2164-16 - Standard Test Method for Directional Difference Test
PreviousNext
Standard
ASTM E2164-16 - Standard Test Method for Directional Difference Test
English language
11 pages
sale 15% off
Preview
sale 15% off
Preview
REDLINE ASTM E2164-16 - Standard Test Method for Directional Difference TestREDLINE ASTM E2164-16 - Standard Test Method for Directional Difference Test
PreviousNext
Standard
REDLINE ASTM E2164-16 - Standard Test Method for Directional Difference Test
English language
11 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: E2164 − 16
Standard Test Method for
1
Directional Difference Test
This standard is issued under the fixed designation E2164; 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 2. Referenced Documents
3
1.1 This test method covers a procedure for comparing two 2.1 ASTM Standards:
products using a two-alternative forced-choice task. E253 Terminology Relating to Sensory Evaluation of Mate-
rials and Products
1.2 This method is sometimes referred to as a paired
E456 Terminology Relating to Quality and Statistics
comparison test or as a 2-AFC (alternative forced choice) test.
E1871 Guide for Serving Protocol for Sensory Evaluation of
1.3 A directional difference test determines whether a dif-
Foods and Beverages
ference exists in the perceived intensity of a specified sensory
2.2 ISO Standard:
attribute between two samples.
ISO 5495 Sensory Analysis—Methodology—Paired Com-
1.4 Directionaldifferencetestingislimitedinitsapplication parison
to a specified sensory attribute and does not directly determine
3. Terminology
the magnitude of the difference for that specific attribute.
Assessors must be able to recognize and understand the
3.1 For definition of terms relating to sensory analysis, see
specifiedattribute.Alackofdifferenceinthespecifiedattribute Terminology E253, and for terms relating to statistics, see
does not imply that no overall difference exists.
Terminology E456.
1.5 This test method does not address preference. 3.2 Definitions of Terms Specific to This Standard:
3.2.1 α (alpha) risk—the probability of concluding that a
1.6 A directional difference test is a simple task for
perceptibledifferenceexistswhen,inreality,onedoesnot(also
assessors, and is used when sensory fatigue or carryover is a
known as type I error or significance level).
concern. The directional difference test does not exhibit the
same level of fatigue, carryover, or adaptation as multiple 3.2.2 β (beta) risk—the probability of concluding that no
sample tests such as triangle or duo-trio tests. For detail on perceptible difference exists when, in reality, one does (also
comparisons among the various difference tests, see Ennis (1), known as type II error).
2
MacRae (2), and O’Mahony and Odbert (3).
3.2.3 one-sided test—a test in which the researcher has an a
priori expectation concerning the direction of the difference. In
1.7 The procedure of the test described in this document
this case, the alternative hypothesis will express that the
consists of presenting a single pair of samples to the assessors.
perceived intensity of the specified sensory attribute is greater
1.8 This standard does not purport to address all of the
(that is,A>B) (or lower (that is,A safety concerns, if any, associated with its use. It is the
the other.
responsibility of the user of this standard to establish appro-
3.2.4 two-sided test—a test in which the researcher does not
priate safety and health practices and determine the applica-
have any a priori expectation concerning the direction of the
bility of regulatory limitations prior to use.
difference. In this case, the alternative hypothesis will express
that the perceived intensity of the specified sensory attribute is
1
This test method is under the jurisdiction ofASTM Committee E18 on Sensory
different from one product to the other (that is, A≠B).
Evaluation and is the direct responsibility of Subcommittee E18.04 on Fundamen-
tals of Sensory.
Current edition approved Oct. 1, 2016. Published October 2016. Originally
3
approved in 2001. Last previous edition approved in 2008 as E2164 – 08. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/E2164-16. contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
2
The boldface numbers in parentheses refer to the list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E2164 − 16
3.2.5 common responses—for a one-sided test, the number advance. Other difference test methods such as the same-
of assessors selecting the sample expected to have a higher different test should be used.
intensity of the specified sensory attribute. Common responses
5.3 Aresulto
...

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: E2164 − 08 E2164 − 16
Standard Test Method for
1
Directional Difference Test
This standard is issued under the fixed designation E2164; 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 test method covers a procedure for comparing two products using a two-alternative forced-choice task.
1.2 This method is sometimes referred to as a paired comparison test or as a 2-AFC (alternative forced choice) test.
1.3 A directional difference test determines whether a difference exists in the perceived intensity of a specified sensory attribute
between two samples.
1.4 Directional difference testing is limited in its application to a specified sensory attribute and does not directly determine the
magnitude of the difference for that specific attribute. Assessors must be able to recognize and understand the specified attribute.
A lack of difference in the specified attribute does not imply that no overall difference exists.
1.5 This test method does not address preference.
1.6 A directional difference test is a simple task for assessors, and is used when sensory fatigue or carryover is a concern. The
directional difference test does not exhibit the same level of fatigue, carryover, or adaptation as multiple sample tests such as
triangle or duo-trio tests. For detail on comparisons among the various difference tests, see Ennis (1), MacRae (2), and O’Mahony
2
and Odbert (3).
1.7 The procedure of the test described in this document consists of presenting a single pair of samples to the assessors.
1.8 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
3
2.1 ASTM Standards:
E253 Terminology Relating to Sensory Evaluation of Materials and Products
E456 Terminology Relating to Quality and Statistics
E1871 Guide for Serving Protocol for Sensory Evaluation of Foods and Beverages
2.2 ISO Standard:
ISO 5495 Sensory Analysis—Methodology—Paired Comparison
3. Terminology
3.1 For definition of terms relating to sensory analysis, see Terminology E253, and for terms relating to statistics, see
Terminology E456.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 α (alpha) risk—the probability of concluding that a perceptible difference exists when, in reality, one does not (also known
as type I error or significance level).
3.2.2 β (beta) risk—the probability of concluding that no perceptible difference exists when, in reality, one does (also known
as type II error).
1
This test method is under the jurisdiction of ASTM Committee E18 on Sensory Evaluation and is the direct responsibility of Subcommittee E18.04 on Fundamentals
of Sensory.
Current edition approved March 1, 2008Oct. 1, 2016. Published April 2008October 2016. Originally approved in 2001. Last previous edition approved in 20072008 as
E2164 – 01 (2007).E2164 – 08. DOI: 10.1520/E2164-08.10.1520/E2164-16.
2
The boldface numbers in parentheses refer to the list of references at the end of this standard.
3
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 ----------------------
E2164 − 16
3.2.3 one-sided test—a test in which the researcher has an a priori expectation concerning the direction of the difference. In this
case, the alternative hypothesis will express that the perceived intensity of the specified sensory attribute is greater (that is, A>B)
(or lower (that is, A 3.2.4 two-sided test—a test in which the researcher does not have any a priori expectation concerning the direction of the
difference. In this case, the alternative hypothesis will express that the perceived intensity of the specified sensory attribute is
different from one product to the other (that is, A≠B).
3.2.5 common responses—for a one-sided test, the number of assessor
...

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 E2943-15(2021)(Guide)
Standard Guide for Two-Sample Acceptance and Preference Testing With Consumers

SIGNIFICANCE AND USE
5.1 Acceptance and preference are the key measurements taken in consumer product testing as either a new product idea is developed into testable prototypes or existing products are evaluated for potential improvements, cost reductions, or other business reasons. Developing products that are preferred overall, or liked as well as, or better, on average, compared to a standard or a competitor, among a defined target consumer group, is usually the main goal of the product development process. Thus, it is necessary to test the consumer acceptability or the preference of a product or prototype compared to other prototypes or potential products, a standard product, or other products in the market. The researcher, with input from her/his stakeholders, has the responsibility to choose appropriate comparison products and scaling or test methods to evaluate them. In the case of a new-to-the-world product, there may or may not be a relevant product for comparison. In this case, a benchmark score or rating may be used to determine acceptability. A product or prototype that is acceptable to the target consumer is one that meets a minimum criterion for liking, and a product that is preferred over an existing product has the potential to be chosen more often than the less-preferred product by the consumer in the marketplace, when all other factors are equal.  
5.2 The external validity (the extent to which the results of a study can be generalized) of both acceptance and preference measures to manage decision risk at all stages of the development cycle is dependent on the ability of the researcher to generalize the results from the respondent sample to the target population at large. This depends both upon the sample of respondents and the way the test is constructed. Within the context of a single test, acceptance measures tell the relative hedonic status of the two samples, quantitatively, as well as where on the hedonic continuum each of the samples falls, that is, “disliked,”...
SCOPE
1.1 This guide covers acceptance and preference measures when each is used in an unbranded, two-sample, product test. Each measure, acceptance, and preference, may be used alone or together in a single test or separated by time. This guide covers how to establish a product’s hedonic or choice status based on sensory attributes alone, rather than brand, positioning, imagery, packaging, pricing, emotional-cultural responses, or other nonsensory aspects of the product. The most commonly used measures of acceptance and preference will be covered, that is, product liking overall as measured by the nine-point hedonic scale and preference measured by choice, either two-alternative forced choice or two-alternative with a “no preference” option.  
1.2 Three of the biggest challenges in measuring a product’s hedonic (overall liking or acceptability) or choice status (preference selection) are determining how many respondents and who to include in the respondent sample, setting up the questioning sequence, and interpreting the data to make product decisions.  
1.3 This guide covers:  
1.3.1 Definition of each type of measure,  
1.3.2 Discussion of the advantages and disadvantages of each,  
1.3.3 When to use each,  
1.3.4 Practical considerations in test execution,  
1.3.5 Risks associated with each,  
1.3.6 Relationship between the two when administered in the same test, and  
1.3.7 Recommended interpretations of results for product decisions.  
1.4 The intended audience for this guide is the sensory consumer professional or marketing research professional (“the researcher”) who is designing, executing, and interpreting data from product tests with acceptance or choice measures, or both.  
1.5 Only two-sample product tests will be covered in this guide. However, the issues and recommended practices raised in this guide often apply to multi-sample tests as well. Detailed coverage of execution tactics, optional types of s...

  • Guide
    15 pages
    English language
    sale 15% off
ASTM
ASTM E3093-20(Guide)
Standard Guide for Structured Small Group Product Evaluations

SIGNIFICANCE AND USE
4.1 Using best practices for SGPE ensures that decisions made will be based on scientific principles, and the outputs obtained will be more objective than those evaluation sessions conducted without this planning, structure, focus, and best practices. These small group evaluations contrast with more formal product tests that include a prequalified participant sample, hypothesis testing, and statistical analysis. Without best sensory practices and procedures, SGPE may be unstructured, unsystematic, difficult to manage, and may lead to outputs that are unclear, not credible, or ignored. Additionally, the use of proper sensory practices reduces bias among participants with specific sample knowledge or a desire to advance an agenda. This guide provides a framework for conceptualizing, organizing, and executing these SGPE.  
4.2 SGPE are used in situations in which formal, hypothesis-driven product evaluations are not required. These include situations in which the decision risk is small or stakeholders feel comfortable in making a decision with the attendant risks, or both. Examples of these situations may include limited availability of samples or other resources, potential patent exposure, or low incidence of target population. The SGPE could be an initial screening step or a precursor test before a more formal product test. In the proper context, SGPE can also be a decision-making tool in and of itself. Using the framework presented here provides a degree of rigor that may be absent when a few people evaluate a product without controlled conditions. A poster presented at the 2009 Pangborn Sensory Science Symposium (1)3 reported the results of a survey on SGPE. 59 % of respondents (N = 92) stated that, at their place of employment, typically, non-sensory professionals organized SGPE. Table 1 summarizes key differences between a typical unstructured product evaluation with a small group not following best practices and an SGPE that follows the best practices outlined...
SCOPE
1.1 This guide covers those occasions in which a small group of individuals (generally between three and ten) with potentially different functional roles and degrees of training in sensory and product evaluation, evaluates a product or series of products for a specific objective, with a pre-identified decision to be made, but without the use of formal hypothesis testing or statistics. In the product testing industry, these are often referred to as “benchings,” “cuttings,” or “bench screenings” or, in the case of food products, “tastings,” “informal tastings,” “team tastings,” or “technical tastings.” In this guide, the term “Small Group Product Evaluation” (SGPE) is used.  
1.2 The aim of this guide is to provide best practices to ensure that SGPE are conducted with sufficient rigor to enable the most appropriate decision or to yield the needed learning while considering the risk. Because the participants may be heterogeneous with respect to functional role, knowledge of the issue at hand, sensory sensitivity, and degree of sensory or product evaluation training, the likelihood of agreement on a path forward is not assured. Additionally, participants may have certain biases with respect to the issue to be decided, because of prior knowledge or their role within the organization. These potential derailers can be addressed through proper planning and execution of an SGPE. When SGPE are unstructured, unfocused and experimental error and biases uncontrolled, the outputs of SGPEs do not inform decisions or deliver the desired learning in a scientific manner. The goal of this document is to elevate the practice of small group product evaluations by outlining a structure, defining decision criteria in advance, and providing guidelines for implementation, drawing upon existing sensory theory and methods. Outputs from these SGPE are used to inform decisions and determine next steps including the risks involved with each of these...

  • Guide
    19 pages
    English language
    sale 15% off
  • Guide
    19 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 E691-23(Practice)
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 ...

  • Standard
    23 pages
    English language
    sale 15% off
  • Standard
    23 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 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 D6646-03(2022)(Test Method)
Standard Test Method for Determination of the Accelerated Hydrogen Sulfide Breakthrough Capacity of Granular and Pelletized Activated Carbon

SIGNIFICANCE AND USE
5.1 This method compares the performance of granular or pelletized activated carbons used in odor control applications, such as sewage treatment plants, pump stations, etc. The method determines the relative breakthrough performance of activated carbon for removing hydrogen sulfide from a humidified gas stream. Other organic contaminants present in field operations may affect the H2S breakthrough capacity of the carbon; these are not addressed by this test. This test does not simulate actual conditions encountered in an odor control application, and is therefore meant only to compare the hydrogen sulfide breakthrough capacities of different carbons under the conditions of the laboratory test.  
5.2 This test does not duplicate conditions that an adsorber would encounter in practical service. The mass transfer zone in the 23 cm column used in this test is proportionally much larger than that in the typical bed used in industrial applications. This difference favors a carbon that functions more rapidly for removal of H2S over a carbon with slower kinetics. Also, the 1 % H2S challenge gas concentration used here engenders a significant temperature rise in the carbon bed. This effect may also differentiate between carbons in a way that is not reflected in the conditions of practical service.  
5.3 This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters less than 2.5 mm. Application of this standard to activated carbons with mean particle diameters (MPD) greater than 2.5 mm will require a larger diameter adsorption column. The ratio of column inside diameter to MPD should be greater than 10 in order to avoid wall effects. In these cases it is suggested that bed superficial velocity and contact time be held invariant at the conditions specified in this standard (4.77 cm/s and 4.8 s). Although not covered by this standard, data obtained from these tests may be reported as in paragraph 12 along with additional ...
SCOPE
1.1 This test method is intended to evaluate the performance of virgin, newly impregnated or in-service, granular or pelletized activated carbon for the removal of hydrogen sulfide from an air stream, under the laboratory test conditions described herein. A humidified air stream containing 1 % (by volume) hydrogen sulfide is passed through a carbon bed until 50 ppm breakthrough of H2S is observed. The H2S adsorption capacity of the carbon per unit volume at 99.5 % removal efficiency (g H2S/cm3 carbon) is then calculated. This test is not necessarily applicable to non-carbon adsorptive materials.  
1.2 This standard as written is applicable only to granular and pelletized activated carbons with mean particle diameters (MPD) less than 2.5 mm. See paragraph 5.3 if activated carbons with larger MPDs are to be tested.  
1.3 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.  
1.4 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.

  • Standard
    9 pages
    English language
    sale 15% off
ASTM
ASTM D5818-22(Practice)
Standard Practice for Exposure and Retrieval of Samples to Evaluate Installation Damage of Geosynthetics

SIGNIFICANCE AND USE
5.1 The ability to maintain design function (for example, reinforcement, separation, barrier, etc.) or design properties (for example, tensile strength, chemical resistance, etc.), or both, of a geosynthetic may be affected by damage to the physical structure of the geosynthetic due to the rigors of field installation. The effect of damage may be assessed by analyzing specimens cut from sample(s) retrieved after installation in a representative test section. Analysis may be performed with visual examination or laboratory testing of specimens from the control sample(s), and from the exhumed sample(s).  
5.2 A uniform practice for installing and retrieving representative sample(s) from a test section is needed to assess installation damage using project-specific or generally accepted, representative materials and procedures. Damage of a specific grade and type of geosynthetic under specific installation procedures may be assessed with sample(s) exhumed from a full-scale test section.
SCOPE
1.1 This practice covers standardized procedures for obtaining samples of geosynthetics from a test section for use in assessment of the effects of damage immediately after installation caused only by the installation techniques. The assessment may include physical testing. This practice is applicable to any geosynthetic except those installed between layers of aggregate or soil modified by a binder.
Note 1: The binder would inhibit the retrieval of the geosynthetic without inflicting further damage to the geosynthetic. Other practices may be suitable for retrieving geosynthetics used in these applications but are out of the scope of this practice.  
1.2 This practice is limited to full-scale test sections and does not address laboratory modeling of field conditions. This practice does not address which test method(s) to use for quantifying installation damage.  
1.3 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.  
1.4 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.

  • Standard
    3 pages
    English language
    sale 15% off
  • Standard
    3 pages
    English language
    sale 15% off
ASTM
ASTM D7252-22(Test Method)
Standard Test Method for Polyurethane Raw Materials: Determination of Monomer and Isomers in Isocyanates

SIGNIFICANCE AND USE
5.1 This test method is used for research or for quality control to characterize isocyanates used in polyurethane products.
SCOPE
1.1 This test method determines the percent by weight of monomeric isomers and total monomer in crude or modified isocyanates. The test method is applicable to methylene di(phenylisocyanate) (MDI) and polymeric (methylene phenylisocyanate) (PMDI). (See Note 1.)  
1.2 Units—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 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.
Note 1: There is no known ISO equivalent to 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.

  • Standard
    6 pages
    English language
    sale 15% off
  • Standard
    6 pages
    English language
    sale 15% off