ISO/IEC 21472:2021

Information technology — Scenario evaluation methodology for user interaction influence in biometric system performance

This document addresses: — requirements for planning, executing and reporting the influence of user interaction on biometric system performance based on scenario test methodologies, considering three kinds of factors: a) factors related to the design, position or condition of the capture device, b) factors depending on users and user attributes, c) factors depending on the interaction of users with the biometric system; — specifications for the definition, establishment and measurement of conditions needed for evaluation, including those relating to equipment; — requirements for establishing a reference evaluation condition (REC) and target evaluation condition(s) (TEC) to compare the influence of user interaction factors; — a specification of the biometric evaluation including requirements for test population, test protocols, data to record, test results; and — procedures for carrying out the overall evaluation. This document does not: — determine which parameters ought to be analysed for a specific biometric modality. This is currently covered in ISO/IEC TR 19795-3; — specify requirements for performing a vulnerability analysis modifying user interaction influence factors; — include procedures for performing usability testing.

Technologies de l'information — Méthodologie d'évaluation des scénarios concernant l'influence de l'interaction de l'utilisateur sur les performances des systèmes biométriques

General Information

• Status: Published
• Publication Date: 05-Oct-2021
• ICS: 35.240.15 - Identification cards. Chip cards. Biometrics
• Technical Committee: ISO/IEC JTC 1/SC 37 - Biometrics
• Drafting Committee: ISO/IEC JTC 1/SC 37/WG 5 - Biometric testing and reporting
• Current Stage: 6060 - International Standard published
• Start Date: 06-Oct-2021
• Due Date: 08-Aug-2021
• Completion Date: 06-Oct-2021

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 21472
First edition
2021-10
Information technology — Scenario
evaluation methodology for user
interaction influence in biometric
system performance
Reference number
ISO/IEC 21472:2021(E)
© ISO/IEC 2021

---------------------- Page: 1 ----------------------
ISO/IEC 21472:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
  © ISO/IEC 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/IEC 21472:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Conformance . 2
5 Overview . 2
5.1 General . 2
5.2 User interaction influence factors . 3
6 Evaluation conditions specification . 4
6.1 General . 4
6.2 Specification of user interaction influence factors . 4
6.2.1 General . 4
6.2.2 Factors depending on the biometric system. 4
6.2.3 Factors depending on the user . 4
6.2.4 Factors depending on the user-biometric system interaction . 6
6.3 Specification of the evaluation conditions . 7
6.3.1 General . 7
6.3.2 Specification of reference evaluation conditions (REC) . 8
6.3.3 Specification of target evaluation conditions (TEC) . 8
6.3.4 Enrolment-related considerations in REC / TEC . 8
6.3.5 Recognition-related considerations in REC / TEC . 8
6.4 Generation of the evaluation conditions. 9
6.5 Control of the evaluation conditions . 9
7 Requirements for planning a user interaction influence testing of biometric systems.9
7.1 Test specification . 9
7.2 Test information . 10
7.3 Test instructions . 10
7.4 Testing order of evaluation conditions . 10
7.5 Test results . 11
Annex A (normative) Requirements for testing and reporting user interaction influence of
biometric systems — Best practices .12
Bibliography .14
iii
© ISO/IEC 2021 – All rights reserved

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ISO/IEC 21472:2021(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance
are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria
needed for the different types of document should be noted. This document was drafted in
accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC
list of patent declarations received (see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 37, Biometrics.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
iv
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ISO/IEC 21472:2021(E)
Introduction
This document describes a methodology for testing and reporting user interaction influence on the
performance of biometric recognition systems. Specifically, it describes a methodology for testing and
reporting that influence.
The performance of biometric systems can vary or can be influenced by user interaction influence
factors. According to ISO/IEC 19795-1:2021, C.2, user physiology, user behaviour, sensors and hardware
(all user interaction influence factors) are some factors that can influence the performance of a
biometric system.
This methodology is a scenario test in which a set of test subjects interacts with a biometric system to
execute transactions when one or more of the following factors is controlled:
— Factors related to the design, position or condition of the capture system.
— Factors depending on the users and their attributes.
— Factors depending on the user interaction with the biometric system.
Testing user interaction influence can be subjective and is not necessarily straightforward. Therefore,
this document is intended to address the main conflicts that arise in such cases.
Within the context of this document, it is important to differentiate between “usability testing” and
“user interaction influence in performance”. Usability testing relates to “the extent to which a product
can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction
in a specified context of use” (ISO/IEC 9241-11:2018). Usability testing involves the measurement of
“how usable” a specific system or product is. Usability testing is addressed in documents including ISO/
IEC TR 25060. On the other hand, "user interaction influence in performance" deals with measuring
how the performance of a biometric system can differ from a reference evaluation, based on subjects
using the system in operational or scenario conditions.
v
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INTERNATIONAL STANDARD ISO/IEC 21472:2021(E)
Information technology — Scenario evaluation
methodology for user interaction influence in biometric
system performance
1 Scope
This document addresses:
— requirements for planning, executing and reporting the influence of user interaction on biometric
system performance based on scenario test methodologies, considering three kinds of factors:
a) factors related to the design, position or condition of the capture device,
b) factors depending on users and user attributes,
c) factors depending on the interaction of users with the biometric system;
— specifications for the definition, establishment and measurement of conditions needed for
evaluation, including those relating to equipment;
— requirements for establishing a reference evaluation condition (REC) and target evaluation
condition(s) (TEC) to compare the influence of user interaction factors;
— a specification of the biometric evaluation including requirements for test population, test protocols,
data to record, test results; and
— procedures for carrying out the overall evaluation.
This document does not:
— determine which parameters ought to be analysed for a specific biometric modality. This is currently
covered in ISO/IEC TR 19795-3;
— specify requirements for performing a vulnerability analysis modifying user interaction influence
factors;
— include procedures for performing usability testing.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 19795-1, Information technology — Biometric performance testing and reporting — Part 1:
Principles and framework
ISO/IEC 19795-2, Information technology — Biometric performance testing and reporting — Part 2:
Testing methodologies for technology and scenario evaluation
ISO/IEC 2382-37, Information technology — Vocabulary — Part 37: Biometrics
ISO/IEC 24779 (all parts), Information technology — Cross-jurisdictional and societal aspects of
implementation of biometric technologies — Pictograms, icons and symbols for use with biometric systems
1
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ISO/IEC 21472:2021(E)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19795-1, ISO/IEC 2382-
37 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
reference evaluation condition
REC
test condition reflecting established device factors, user factors or user interaction factors
Note 1 to entry: Results generated under these test conditions are compared against results generated under
corresponding target evaluation conditions (3.2).
3.2
target evaluation condition
TEC
test condition reflecting new or alternative device factors, user factors or user interaction factors
Note 1 to entry: Results generated under these test conditions are compared against results generated under
corresponding reference evaluation conditions (3.1).
3.3
user interaction influence in performance
measurement of how the performance of a biometric system can differ from a reference evaluation,
based on subjects using the system in operational or scenario conditions
3.4
usability testing
testing relating to the extent to which a product can be used by specified users to achieve specified
goals with effectiveness, efficiency and satisfaction in a specified context of use
Note 1 to entry: See ISO/IEC 9241-11.
4 Conformance
To conform to this document, a user interaction influence performance evaluation shall implement the
requirements contained herein, including one reference evaluation condition (REC) and at least one
target evaluation condition (TEC).
5 Overview
5.1 General
Testing the influence of user interaction in the performance of a biometric system entails execution
of one scenario evaluation under reference evaluation conditions (REC) and at least one evaluation
under target evaluation conditions (TEC). These evaluations are identical except for changes to the user
interaction influence factors being studied.
For each set of condition(s), test subjects interact with the biometric system as many times as required.
The number of times the interaction is repeated shall be defined at the time of the evaluation design,
considering parameters such as: available time for the evaluation, availability of test crew, effort to be
applied for each test crew subject, cost, etc. Biometric system recognition outcomes and (optionally)
2
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ISO/IEC 21472:2021(E)
test subject interactions are recorded. From such results, it is possible to calculate biometric system
performance (e.g. error rates and throughput rates) for the specific evaluation condition(s).
By comparing performance results generated under REC and TEC, the influence associated with user
interaction factor(s) can be quantified. A schema of the evaluation methodology model is shown in
Figure 1. In scenario evaluations, biometric systems are assessed in modelled environments considering
a real-world target application and population. Requirements for scenario testing and reporting are
defined in ISO/IEC 19795-2.
Figure 1 — Methodology evaluation schema of user interaction influence in biometric system
performance
Each evaluation condition is specified to analyse one or a combination of user interaction influence
factors. The evaluation methodology allows for conditions to be tailored according to the objectives of
the evaluation. These objectives can consider three general aspects:
— the design, position or condition of the biometric system and/or its biometric capture device;
— the potential users, their attributes or the state of such attributes;
— parameters that can affect the interaction process such as guidance, training or feedback.
Depending on the biometric system, its capture device, the potential users and the final application,
certain aspects are more critical than others. ISO/IEC TR 19795-3 discusses modality-specific aspects
that can be relevant to user interaction influence testing. Parties involved in the evaluation shall select
which aspects are indispensable for analysis. TEC can encompass one or multiple user interaction
influence factors.
5.2 User interaction influence factors
In order to compare TECs and RECs, it is also necessary to define the user interaction influence factors.
There are three kinds of factors in the interaction between users and biometric systems:
— Factors depending on the biometric capture device, e.g. design, position or condition.
— Factors depending on users and user attributes, e.g. physical features or experience with the device.
— Factors depending on the interaction of users with the biometric system, e.g. feedback provided by
device to user.
3
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ISO/IEC 21472:2021(E)
6 Evaluation conditions specification
6.1 General
The individual(s) carrying out the experiment shall specify the user interaction influence conditions to
be evaluated, taking into consideration the following:
— user interaction influence factors;
— RECs and TECs;
— enrolment and recognition-based factors.
6.2 Specification of user interaction influence factors
6.2.1 General
The definition of the evaluation conditions consists of determining which user interaction influence
factors will be assessed. The different kinds of factors that can be selected are provided in the following
subclauses. Other factors that can be measured may be considered.
6.2.2 Factors depending on the biometric system
User interaction can be influenced by the design, position or condition of the biometric capture system.
These factors, examples of which are listed in Table 1, can cause the failure of the biometric capture
process or result in a biometric sample of poor quality. Table 1 categorizes factors as software- and
hardware-related, and includes an example for each factor and/or its possible variations.
Table 1 — Examples of system-dependent user interaction influence factors
Type Factor Example REC Example TEC 1 Example TEC 2
Remote
Embedded
Software Process Location server-based
matching
matching
Device positioned Device positioned Device positioned
Height
at 1,20 m height at 1 m height at 1,50 m height
Swipe sensor hori- Swipe sensor
Rotation
zontally vertically
Position Orientation
Hardware On a table without On a table with On a table with
Incline
inclination 15º inclination 30º inclination
Embedded in a
Mobility Attached to a wall
mobile device
Condition Clean sensor Dirty sensor
6.2.3 Factors depending on the user
The users’ attributes (including biometrics) can also affect the process of capturing the biometric
sample. User interaction influence factors can be associated with a test subject (i.e. the person who
presents biometric characteristics).
In this document, the users are the participants of the evaluations or the personnel who interact with
the biometric devices/system (depending on the evaluation characteristics). Guidance on best practice
and on how to measure the operators’ influence in the evaluations’ performance is provided in ISO/IEC

TR 29189. Further information on the accessibility and usability of biometric systems is given in ISO/
IEC TR 24714-1 and in ISO/IEC TR 29194.
4
  © ISO/IEC 2021 –
...

INTERNATIONAL ISO/IEC
STANDARD 21472
First edition
Information technology — Scenario
evaluation methodology for user
interaction influence in biometric
system performance
PROOF/ÉPREUVE
Reference number
ISO/IEC 21472:2021(E)
©
ISO/IEC 2021

---------------------- Page: 1 ----------------------
ISO/IEC 21472:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/IEC 21472:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Conformance . 2
5 Overview . 2
5.1 General . 2
5.2 User interaction influence factors . 3
6 Evaluation conditions specification . 4
6.1 General . 4
6.2 Specification of user interaction influence factors. 4
6.2.1 General. 4
6.2.2 Factors depending on the biometric system . 4
6.2.3 Factors depending on the user . 4
6.2.4 Factors depending on the user-biometric system interaction . 6
6.3 Specification of the evaluation conditions . 7
6.3.1 General. 7
6.3.2 Specification of reference evaluation conditions (REC). 8
6.3.3 Specification of target evaluation conditions (TEC). 8
6.3.4 Enrolment-related considerations in REC / TEC . 8
6.3.5 Recognition-related considerations in REC / TEC . 8
6.4 Generation of the evaluation conditions . 9
6.5 Control of the evaluation conditions . 9
7 Requirements for planning a user interaction influence testing of biometric systems .9
7.1 Test specification . 9
7.2 Test information .10
7.3 Test instructions .10
7.4 Testing order of evaluation conditions .10
7.5 Test results.11
Annex A (normative) Requirements for testing and reporting user interaction influence of
biometric systems — Best practices .12
Bibliography .14
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE iii

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ISO/IEC 21472:2021(E)

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for
the different types of document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives or www .iec .ch/ members
_experts/ refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents) or the IEC
list of patent declarations received (see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html. In the IEC, see www .iec .ch/ understanding -standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 37, Biometrics.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html and www .iec .ch/ national
-committees.
iv PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved

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ISO/IEC 21472:2021(E)

Introduction
This document describes a methodology for testing and reporting user interaction influence on the
performance of biometric recognition systems. Specifically, it describes a methodology for testing and
reporting that influence.
The performance of biometric systems can vary or can be influenced by user interaction influence
factors. According to 19795-1:2006, C.2, user physiology, user behaviour, sensors and hardware (all
user interaction influence factors) are some factors that can influence the performance of a biometric
system.
This methodology is a scenario test in which a set of test subjects interacts with a biometric system to
execute transactions when one or more of the following factors is controlled:
— Factors related to the design, position or condition of the capture system.
— Factors depending on the users and their attributes.
— Factors depending on the user interaction with the biometric system.
Testing user interaction influence can be subjective and is not necessarily straightforward. Therefore,
this document is intended to address the main conflicts that arise in such cases.
Within the context of this document, it is important to differentiate between “usability testing” and
“user interaction influence in performance”. Usability testing relates to “the extent to which a product
can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction
in a specified context of use” (ISO/IEC 9241-11:2018). Usability testing involves the measurement of
“how usable” a specific system or product is. Usability testing is addressed in documents including
ISO/IEC TR 25060. On the other hand, "user interaction influence in performance" deals with measuring
how the performance of a biometric system can differ from a reference evaluation, based on subjects
using the system in operational or scenario conditions.
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO/IEC 21472:2021(E)
Information technology — Scenario evaluation
methodology for user interaction influence in biometric
system performance
1 Scope
This document addresses:
— requirements for planning, executing and reporting the influence of user interaction on biometric
system performance based on scenario test methodologies, considering three kinds of factors:
a) factors related to the design, position or condition of the capture device,
b) factors depending on users and user attributes,
c) factors depending on the interaction of users with the biometric system;
— specifications for the definition, establishment and measurement of conditions needed for
evaluation, including those relating to equipment;
— requirements for establishing a reference evaluation condition (REC) and target evaluation
condition(s) (TEC) to compare the influence of user interaction factors;
— a specification of the biometric evaluation including requirements for test population, test protocols,
data to record, test results; and
— procedures for carrying out the overall evaluation.
This document does not
— determine which parameters ought to be analysed for a specific biometric modality. This is currently
covered in ISO/IEC TR 19795-3;
— specify requirements for performing a vulnerability analysis modifying user interaction influence
factors;
— include procedures for performing usability testing.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 19795-1, Information technology — Biometric performance testing and reporting — Part 1:
Principles and framework
ISO/IEC 19795-2, Information technology — Biometric performance testing and reporting — Part 2:
Testing methodologies for technology and scenario evaluation
ISO/IEC 2382-37, Information technology — Vocabulary — Part 37: Biometrics
ISO/IEC 24779 (all parts), Information technology — Cross-jurisdictional and societal aspects of
implementation of biometric technologies — Pictograms, icons and symbols for use with biometric systems
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE 1

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ISO/IEC 21472:2021(E)

3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19795-1, ISO/IEC 2382-37
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
reference evaluation condition
REC
test condition reflecting established device factors, user factors or user interaction factors
Note 1 to entry: Results generated under these test conditions are compared against results generated under
corresponding target evaluation conditions (3.2).
3.2
target evaluation condition
TEC
test condition reflecting new or alternative device factors, user factors or user interaction factors
Note 1 to entry: Results generated under these test conditions are compared against results generated under
corresponding reference evaluation conditions (3.1).
3.3
user interaction influence in performance
measurement of how the performance of a biometric system can differ from a reference evaluation,
based on subjects using the system in operational or scenario conditions
3.4
usability testing
testing relating to the extent to which a product can be used by specified users to achieve specified
goals with effectiveness, efficiency and satisfaction in a specified context of use
Note 1 to entry: See ISO/IEC 9241-11.
4 Conformance
To conform to this document, a user interaction influence performance evaluation shall implement the
requirements contained herein, including one reference evaluation condition (REC) and at least one
target evaluation condition (TEC).
5 Overview
5.1 General
Testing the influence of user interaction in the performance of a biometric system entails execution
of one scenario evaluation under reference evaluation conditions (REC) and at least one evaluation
under target evaluation conditions (TEC). These evaluations are identical except for changes to the user
interaction influence factors being studied.
For each set of condition(s), test subjects interact with the biometric system as many times as required.
The number of times the interaction is repeated shall be defined at the time of the evaluation design,
considering parameters such as: available time for the evaluation, availability of test crew, effort to be
applied for each test crew subject, cost, etc. Biometric system recognition outcomes and (optionally)
2 PROOF/ÉPREUVE © ISO/IEC 2021 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/IEC 21472:2021(E)

test subject interactions are recorded. From such results, it is possible to calculate biometric system
performance (e.g. error rates and throughput rates) for the specific evaluation condition(s).
By comparing performance results generated under REC and TEC, the influence associated with user
interaction factor(s) can be quantified. A schema of the evaluation methodology model is shown in
Figure 1. In scenario evaluations, biometric systems are assessed in modelled environments considering
a real-world target application and population. Requirements for scenario testing and reporting are
defined in ISO/IEC 19795-2.
Figure 1 — Methodology evaluation schema of user interaction influence in biometric system
performance
Each evaluation condition is specified to analyse one or a combination of user interaction influence
factors. The evaluation methodology allows for conditions to be tailored according to the objectives of
the evaluation. These objectives can consider three general aspects:
— the design, position or condition of the biometric system and/or its biometric capture device;
— the potential users, their attributes or the state of such attributes;
— parameters that can affect the interaction process such as guidance, training or feedback.
Depending on the biometric system, its capture device, the potential users and the final application,
certain aspects are more critical than others. ISO/IEC TR 19795-3 discusses modality-specific aspects
that can be relevant to user interaction influence testing. Parties involved in the evaluation shall select
which aspects are indispensable for analysis. TEC can encompass one or multiple user interaction
influence factors.
5.2 User interaction influence factors
In order to compare TECs and RECs, it is also necessary to define the user interaction influence factors.
There are three kinds of factors in the interaction between users and biometric systems:
— Factors depending on the biometric capture device, e.g. design, position or condition.
— Factors depending on users and user attributes, e.g. physical features or experience with the device.
— Factors depending on the interaction of users with the biometric system, e.g. feedback provided by
device to user.
© ISO/IEC 2021 – All rights reserved PROOF/ÉPREUVE 3

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ISO/IEC 21472:2021(E)

6 Evaluation conditions specification
6.1 General
The individual(s) carrying out the experiment shall specify the user interaction influence conditions to
be evaluated, taking into consideration the following:
— user interaction influence factors;
— RECs and TECs;
— enrolment and recognition-based factors.
6.2 Specification of user interaction influence factors
6.2.1 General
The definition of the evaluation conditions consists of determining which user interaction influence
factors will be assessed. The different kinds of factors that can be selected are provided in the following
subclauses. Other factors that can be measured may be considered.
6.2.2 Factors depending on the biometric system
User interaction can be influenced by the design, position or condition of the biometric capture system.
These factors, examples of which are listed in Table 1, can cause the failure of the biometric capture
process or result in a biometric sample of poor quality. Table 1 categorizes factors as software- and
hardware-related, and includes an example for each factor and/or its possible variations.
Table 1 — Examples of system-dependent user interaction influence factors
Type Factor Example REC Example TEC 1 Example TEC 2
Remote serv- Embedded match-
Software Process Location
er-based matching ing
Device positioned Device positioned Device positioned
Height
at 1,20 m height at 1 m height at 1,50 m height
Swipe sensor hori- Swipe sensor
Rotation
zontally vertically
Position Orientation
Hardware On a table without On a table with On a table with
Incline
inclination 15º inclination 30º inclination
Embedded in a
Mobility Attached to a wall
mobile device
Condition Clean sensor Dirty sensor
6.2.3 Factors depending on the user
The users’ attributes (including biometrics) can also affect the process of capturing the biometric
sample. User interaction influence factors can be associated with a test subject (i.e. the person who
presents biometric characteristics).
In this document, the users are the participants of the evaluations or the personnel who interact
with the biometric devices/system (depending on the evaluation characteristics). Guidance on best
practice and on how to measure the operators’ influence in the evaluations’ performance is provided in

ISO/IEC TR 29189. Further information on the accessibility and usability of biometric systems is given
in ISO/IEC TR 24714-1 and in ISO/IEC TR 29194.
Table 2 categorizes user interaction influence factors
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