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ASTM E2164-08

(Test Method)

Standard Test Method for Directional Difference Test

Standard Test Method for Directional Difference Test

SIGNIFICANCE AND USE
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.
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.
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.
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).  
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
Historical
Publication Date
29-Feb-2008
ICS
19.020 - Test conditions and procedures in general
Technical Committee
E18 - Sensory Evaluation
Drafting Committee
E18.04 - Test Methods
Current Stage
Ref Project

Relations

Replaces
ASTM E2164-01(2007) - Standard Test Method for Directional Difference Test
Effective Date
01-Mar-2008
Replaced By
ASTM E2164-16 - Standard Test Method for Directional Difference 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-Mar-2008
Referred By
ASTM E2263-12(2018) - Standard Test Method for Paired Preference Test
Effective Date
01-Mar-2008
Referred By
ASTM E1958-22 - Standard Guide for Sensory Claim Substantiation
Effective Date
01-Mar-2008
Referred By
ASTM D5237-14(2019) - Standard Guide for Evaluating Fabric Softeners
Effective Date
01-Mar-2008
Referred By
ASTM E460-21 - Standard Practice for Determining Effect of Packaging on Food and Beverage Products During Storage
Effective Date
01-Mar-2008
Referred By
ASTM E3093-20 - Standard Guide for Structured Small Group Product Evaluations
Effective Date
01-Mar-2008

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Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E2164 − 08
StandardTest 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 March 1, 2008. Published April 2008. Originally
3
approved in 2001. Last previous edition approved in 2007 as E2164 – 01 (2007). For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/E2164-08. 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 − 08
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 Aresultofnosignificantdifferenceinaspecificattribute
couldalsobedefinedintermsoflowerintensityoftheattribute
does not ensure that there are no differences between
...

This document is not anASTM standard and is intended only to provide the user of anASTM 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:E2164–01 (Reapproved 2007) Designation: E 2164 – 08
Standard Test Method for
1
Directional Difference Test
This standard is issued under the fixed designation E 2164; 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 (e) 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 Adirectional 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 Adirectional 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 referencess.Ennis (1), , MacRae (2),
2
and , and O’Mahony 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:
E 253 Terminology Relating to Sensory Evaluation of Materials and Products
E 456 Terminology Relating to Quality and Statistics
E 1871 Guide for Serving Protocol for Sensory Evaluation of Foods and Beverages
2.2 ASTM Publications:
Manual 26Sensory Testing Methods, 2nd Edition
STP 758Guidelines for the Selection and Training of Sensory Panel Members
STP 913Guidelines. Physical Requirements for Sensory Evaluation Laboratories
2.3 ISO Standard:
ISO 5495 Sensory Analysis—Methodology—Paired Comparison
3. Terminology
3.1 For definition of terms relating to sensory analysis, see Terminology E 253, and for terms relating to statistics, see
Terminology E 456.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 a(alpha)risk—theprobabilityofconcludingthataperceptibledifferenceexistswhen,inreality,onedoesnot(alsoknown
as type I error or significance level).
3.2.2 b (beta) risk—the probability of concluding that no perceptible difference exists when, in reality, one does (also known
as type II error).
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
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.
CurrenteditionapprovedSept.March1,2007.2008.PublishedJanuaryApril2008.Originallyapprovedin2001.Lastpreviouseditionapprovedin20012007asE 2164 – 01
(2007).
2
The boldface numbers in parentheses refer to the list of references at the end of this standard.
3
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM 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 ----------------------
E2164–08
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
...

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ASTM
ASTM E1188-23(Practice)
Standard Practice for Collection and Preservation of Information and Physical Items by a Technical Investigator

SIGNIFICANCE AND USE
2.1 This practice is intended for use by any technical investigator when investigating an incident that can be reasonably expected to be the subject of litigation. The intent is to obtain sufficient information and physical items to identify evidence associated with the incident and to preserve it for analysis.  
2.2 The quality of evidence may change with time, therefore, special effort should be taken to capture and preserve evidence in an expeditious manner. This practice sets forth guidelines for the collection and preservation of evidence for further analysis.  
2.3 Evidence that has been collected and preserved is identified with, and traceable to, the incident. This practice sets forth guidelines for such procedures.
SCOPE
1.1 This practice covers guidelines for the collection and preservation of information and physical items by any technical investigator pertaining to an incident that can be reasonably expected to be the subject of litigation.  
1.2 This practice describes generally accepted professional principles and operations, although the facts and issues of each situation require consideration, and frequently involve matters not expressly dealt with herein. Deviations from this practice should be based on specific articulable circumstances.  
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.

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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.

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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.

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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 ...

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