ASTM E2161-23c

Standard Terminology Relating to Performance Validation in Thermal Analysis and Rheology

SCOPE
1.1 Validation of methods and apparatus is requested or required for quality initiatives or where results may be used for legal purposes.  
1.2 This standard provides terminology relating to validating performance of thermal analysis and rheology methods and instrumentation. Terms that are generally understood or defined adequately in other readily available sources are not included.  
1.3 The terminology described in this standard is that of the validation process and may differ from that traditionally encountered in ASTM standards.  
1.4 A definition is a single sentence with additional information included in a Discussion.  
1.5 This terminology only includes those terms that are included in an ASTM standard or for which some action is under consideration. It is not intended as an all-inclusive listing of terms relating to performance validation.  
1.6 Terminology commonly used in the study of precision and bias, in thermal analysis, rheology, and thermophysical properties may be found in Practice E177 and Terminologies E473 and E1142. Additional information on method validation may be found in the U.S. Pharmacopeia and National Formulary.2  
1.7 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.

General Information

• Status: Published
• Publication Date: 31-Jul-2023
• ICS: 01.040.17 - Metrology and measurement. Physical phenomena (Vocabularies)
• ICS: 17.200.01 - Thermodynamics in general
• Technical Committee: E37 - Thermal Measurements
• Drafting Committee: E37.03 - Nomenclature and Definitions

Relations

• Refers: ASTM E1142-23b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Oct-2023
• Refers: ASTM E473-23b - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 01-Oct-2023
• Refers: ASTM E1142-15 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-May-2015
• Refers: ASTM E473-14 - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 15-Aug-2014
• Refers: ASTM E1142-14b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Aug-2014
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E1142-14a - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Apr-2014
• Refers: ASTM E1142-14 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Feb-2014
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E1142-12 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Sep-2012
• Refers: ASTM E1142-11b - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Aug-2011
• Refers: ASTM E473-11a - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 15-Jun-2011
• Refers: ASTM E1142-11a - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 15-Jun-2011
• Refers: ASTM E473-11 - Standard Terminology Relating to Thermal Analysis and Rheology
• Effective Date: 01-Apr-2011
• Refers: ASTM E1142-11 - Standard Terminology Relating to Thermophysical Properties
• Effective Date: 01-Apr-2011

Overview

ASTM E2161-23c is the standard terminology developed by ASTM International for performance validation in the fields of thermal analysis and rheology. This reference document provides a comprehensive vocabulary essential for professionals tasked with the validation of analytical methods and instrumentation. Performance validation is increasingly critical in quality assurance, regulatory compliance, and legal contexts where reliable and precise results in thermal and rheological measurements are necessary.

By establishing unified terminology, ASTM E2161-23c enhances mutual understanding among stakeholders, supports effective communication, and underpins robust validation processes in laboratory and industrial settings. The terminology is especially relevant for those engaged in validating testing methods, interpreting data outputs, and ensuring conformance to global standards.

Key Topics

ASTM E2161-23c focuses on terminology specific to the validation of performance in thermal analysis and rheology, with terms organized to support clear and precise communication. Major themes covered include:

• Performance Validation: Definitions related to the process of documenting and confirming that methods and apparatus perform as intended.
• Measurement Concepts: Terms such as absolute measurement, comparative measurement, accuracy, precision, repeatability, reproducibility, standard deviation, and variance.
• Calibration and Reference Materials: Concepts like calibration, certificate, certification, certified reference material, standard reference material, and reference material.
• Statistical Tools: Key terms including coefficient of determination (R²), correlation coefficient, pooled mean, linearity, and bias.
• Analytical Parameters: Definitions for resolvability (resolution), sensitivity, selectivity, detection and quantitation limits, noise (short and long term), and time constant.
• Process and Quality Control: Discussion of evaluation, verification, conformance, pilot study, and interlaboratory studies.

The standard provides clear, concise definitions, with many entries supplemented by a “Discussion” for added context.

Applications

Understanding and applying the terminology from ASTM E2161-23c is vital across a range of industries and scientific domains:

• Laboratory Quality Assurance: Ensures the use of standardized language in documentation, method validation, and lab audits.
• Regulated Environments: Supports compliance with legal and quality requirements in pharmaceutical, chemical, and materials testing industries.
• Instrument Calibration and Maintenance: Provides the vocabulary necessary for professionals responsible for calibration, routine checks, and performance verification of rheological and thermal analysis equipment.
• Research and Development: Facilitates precise communication during method development, pilot studies, and inter- or intra-laboratory validation studies.
• Educational and Training Programs: Serves as a foundational reference for the instruction of best practices in performance validation.

By employing the standardized terminology, practitioners ensure clarity and consistency when comparing methods, reporting data, and interpreting results in thermal analysis and rheology.

Related Standards

ASTM E2161-23c is part of a broader framework of international standards focusing on measurement quality and performance validation. The following are closely associated documents:

• ASTM E177 - Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E473 - Terminology Relating to Thermal Analysis and Rheology
• ASTM E1142 - Terminology Relating to Thermophysical Properties
• U.S. Pharmacopeia (USP) and National Formulary (NF): Additional resources for best practices and further terminology on method validation.

These referenced standards work in tandem to promote standardization, quality control, and reliable analytical results in scientific and industrial settings worldwide.

Keywords: performance validation, terminology, ASTM E2161-23c, thermal analysis, rheology, calibration, quality assurance, method validation, precision, accuracy

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: E2161 − 23c
Standard Terminology Relating to
Performance Validation in Thermal Analysis and Rheology
This standard is issued under the fixed designation E2161; 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
2.1 ASTM Standards:
1.1 Validation of methods and apparatus is requested or
E177 Practice for Use of the Terms Precision and Bias in
required for quality initiatives or where results may be used for
ASTM Test Methods
legal purposes.
E473 Terminology Relating to Thermal Analysis and Rhe-
1.2 This standard provides terminology relating to validat-
ology
ing performance of thermal analysis and rheology methods and
E1142 Terminology Relating to Thermophysical Properties
instrumentation. Terms that are generally understood or defined
3. Terminology
adequately in other readily available sources are not included.
absolute measurement, n—an analytical measurement or
1.3 The terminology described in this standard is that of the
result in which the measured variable(s) are evaluated using
validation process and may differ from that traditionally
theoretical principles and fundamental physical constants,
encountered in ASTM standards.
without using a reference material for calibration.
1.4 A definition is a single sentence with additional infor-
accuracy, n—the agreement between an experimentally deter-
mation included in a Discussion.
mined value and the accepted reference value.
1.5 This terminology only includes those terms that are
DISCUSSION—Accuracy is also known as bias in ASTM practice.
included in an ASTM standard or for which some action is
analyte, n—the specific component measured in an analysis.
under consideration. It is not intended as an all-inclusive listing
of terms relating to performance validation.
baseline, n—the resultant analytical trace when no test speci-
men is present.
1.6 Terminology commonly used in the study of precision
and bias, in thermal analysis, rheology, and thermophysical
bias, n—a constant or systematic difference between the test
properties may be found in Practice E177 and Terminologies
results and an accepted reference value.
E473 and E1142. Additional information on method validation
blank, n—the measured value obtained when a specific com-
may be found in the U.S. Pharmacopeia and National Formu-
2 ponent is not present during the measurement.
lary.
bow, n—the maximum deviation between an actual instrument
1.7 This international standard was developed in accor-
reading and the reading predicted by a straight line drawn
dance with internationally recognized principles on standard-
between upper and lower calibration points, expressed as a
ization established in the Decision on Principles for the
percent of full scale.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
calibration, n—the act or process of determining the relation-
Barriers to Trade (TBT) Committee.
ship between a set of standard units of measurement and the
output of an instrument or test method.
DISCUSSION—Calibration is intended to improve the reproducibility
This terminology is under the jurisdiction of ASTM Committee E37 on and bias (accuracy) of a measurement so that results are consistent with
Thermal Measurements and is the direct responsibility of Subcommittee E37.03 on
other measurements.
Nomenclature and Definitions.
Current edition approved Aug. 1, 2023. Published August 2023. Originally
approved in 2001. Last previous edition approved in 2023 as E2161 – 23b. DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/E2161-23C. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Available from U.S. Pharmacopeial Convention (USP), 12601 Twinbrook Standards volume information, refer to the standard’s Document Summary page on
Pkwy., Rockville, MD 20852-1790, http://www.usp.org. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2161 − 23c
DISCUSSION—Typical figures-of-merit include accuracy, repeatability,
certificate, n—a formal document testifying to the truth of a
sensitivity, etc.
matter (see also certification).
full-width at half-maximum (FWHM), n—the difference
certification, n—process of issuing a formal document testi-
between the two extreme values of a peak of the independent
fying to the truth of a matter.
variable at which the dependent variable is equal to half of
DISCUSSION—Includes conditions (such as accreditation), materials
its maximum value.
(such as reference materials), processes (such as calibration), and the
like.
intercept, n—in linear or multiple linear regression, the
certified reference material, n—a reference material lot, the
expected dependent variable value when all independent
property(ies) of which, determined by measurement is/are
variables are zero.
certified by an identified organization and found on an
DISCUSSION—For example, in linear regression, when data is fit to the
accompanying certificate.
equation Y = m X + b, where Y is the dependent variable, X is the
DISCUSSION—Each certified value should be is accompanied by an
independent variable, m is the slope, then b is the intercept.
uncertainty at a stated level of confidence.
interlaboratory study, ILS, n—a study undertaken to provide
coefficient of determination, R , n—a measure of how well a
between laboratory precision and accuracy information for a
statistical model approximates the real data
test method.
DISCUSSION—Goodness-of-fit is a synonym for coefficient of deter-
mination.
interlaboratory testing, n—evaluation of a test method in
more than one laboratory by analyzing data obtained from
DISCUSSION—The coefficient of determination equals the square of
the correlation coefficient. one or more materials that are as homogeneous as practical.
DISCUSSION—R is the fraction of the variance explained by the
intralaboratory study, n—a study undertaken to provide
correlation. In contrast, 1- R is the fraction of the variance unexplained
within laboratory precision and accuracy information for a
by the correlation. The value of the coefficient of determination varies
test method.
from 0 (no correlation) to 1 (perfect correlation).
linearity, n—the maximum deviation of output points from the
coefficient of variation, n—the standard deviatio
...

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: E2161 − 23b E2161 − 23c
Standard Terminology Relating to
Performance Validation in Thermal Analysis and Rheology
This standard is issued under the fixed designation E2161; 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 Validation of methods and apparatus is requested or required for quality initiatives or where results may be used for legal
purposes.
1.2 This standard provides terminology relating to validating performance of thermal analysis and rheology methods and
instrumentation. Terms that are generally understood or defined adequately in other readily available sources are not included.
1.3 The terminology described in this standard is that of the validation process and may differ from that traditionally encountered
in ASTM standards.
1.4 A definition is a single sentence with additional information included in a Discussion.
1.5 This terminology only includes those terms that are included in an ASTM standard or for which some action is under
consideration. It is not intended as an all-inclusive listing of terms relating to performance validation.
1.6 Terminology commonly used in the study of precision and bias, in thermal analysis, rheology, and thermophysical properties
may be found in Practice E177 and Terminologies E473 and E1142. Additional information on method validation may be found
in the U.S. Pharmacopeia and National Formulary.
1.7 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
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E473 Terminology Relating to Thermal Analysis and Rheology
E1142 Terminology Relating to Thermophysical Properties
This terminology is under the jurisdiction of ASTM Committee E37 on Thermal Measurements and is the direct responsibility of Subcommittee E37.03 on Nomenclature
and Definitions.
Current edition approved June 1, 2023Aug. 1, 2023. Published June 2023August 2023. Originally approved in 2001. Last previous edition approved in 2023 as
E2161 – 23a.E2161 – 23b. DOI: 10.1520/E2161-23B.10.1520/E2161-23C.
Available from U.S. Pharmacopeial Convention (USP), 12601 Twinbrook Pkwy., Rockville, MD 20852-1790, http://www.usp.org.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
E2161 − 23c
3. Terminology
absolute measurement, n—an analytical measurement or result in which the measured variable(s) are evaluated using
theoretical principles and fundamental physical constants, without using a reference material for calibration.
accuracy, n—the agreement between an experimentally determined value and the accepted reference value.
DISCUSSION—
Accuracy is also known as bias in ASTM practice.
analyte, n—the specific component measured in an analysis.
baseline, n—the resultant analytical trace when no test specimen is present.
bias, n—a constant or systematic difference between the test results and an accepted reference value.
blank, n—the measured value obtained when a specific component is not present during the measurement.
bow, n—the maximum deviation between an actual instrument reading and the reading predicted by a straight line drawn
between upper and lower calibration points, expressed as a percent of full scale.
calibration, n—the act or process of determining the relationship between a set of standard units of measurement and the output
of an instrument or test method.
DISCUSSION—
Calibration is intended to improve the reproducibility and bias (accuracy) of a measurement so that results are consistent with other measurements.
certificate, n—a formal document testifying to the truth of a matter (see also certification).
certification, n—process of issuing a formal document testifying to the truth of a matter.
DISCUSSION—
Includes conditions (such as accreditation), materials (such as reference materials), processes (such as calibration), and the like.
certified reference material, n—a reference material lot, the property(ies) of which, determined by measurement is/are certified
by an identified organization and found on an accompanying certificate.
DISCUSSION—
Each certified value should be is accompanied by an uncertainty at a stated level of confidence.
coefficient of determination, R ,n—a measure of how well a statistical model approximates the real data
DISCUSSION—
Goodness-of-fit is a synonym for coefficient of determination.
DISCUSSION—
The coefficient of determination equals the square of the correlation coefficient.
DISCUSSION—
2 2
R is the fraction of the variance explained by the correlation. In contrast, 1- R is the fraction of the variance unexplained by the correlation. The value
of the coefficient of determination varies from 0 (no correlation) to 1 (perfect correlation).
coefficient of variation, n—the standard deviation divided by the value of the parameter measured.
comparative measurement, n—an analytical measurement obtained by comparing a sample having an unknown quantity of a
selected property with a sample having a known quantity of that property.
DISCUSSION—
Comparative methods use calibration with a reference material(s) or analyte.
E2161 − 23c
conformance, n—agreement of a product, process or service with specification requirements.
correlation coefficient, R,n—a statistical measure of the strength and direction of the linear relationship between two variables.
DISCUSSION—
The strength of the correlation varies from 0 (no correlation) to 61 (perfect correlation). The sign indicates direction. A positive sign indicates that
the two variables move in the same direction. A negative sign indicates the one variable decrease while the other increases.
DISCUSSION—
The square of the correlation coefficient is known as the coefficient of determination.
detection limit, n—the minimum quantity of analyte that can be reliably detected but
...