EN ISO 9241-110:2020

SLOVENSKI STANDARD
01-december-2020
Nadomešča:
SIST EN ISO 9241-110:2007
Ergonomija medsebojnega vpliva človek-sistem - 110. del: Načela medsebojnega
delovanja (ISO 9241-110:2020)
Ergonomics of human-system interaction - Part 110: Interaction principles (ISO 9241-
110:2020)
Ergonomie der Mensch-System-Interaktion - Teil 110: Interaktionsprinzipien (ISO 9241-
110:2020)
Ergonomie de l'interaction homme-système - Partie 110: Titre manque (ISO 9241-
110:2020)
Ta slovenski standard je istoveten z: EN ISO 9241-110:2020
ICS:
13.180 Ergonomija Ergonomics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 9241-110
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2020
EUROPÄISCHE NORM
ICS 13.180 Supersedes EN ISO 9241-110:2006
English Version
Ergonomics of human-system interaction - Part 110:
Interaction principles (ISO 9241-110:2020)
Ergonomie de l'interaction homme-système - Partie Ergonomie der Mensch-System-Interaktion - Teil 110:
110: Principes d'interaction (ISO 9241-110:2020) Interaktionsprinzipien (ISO 9241-110:2020)
This European Standard was approved by CEN on 23 May 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

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United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9241-110:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 9241-110:2020) has been prepared by Technical Committee ISO/TC 159
"Ergonomics" in collaboration with Technical Committee CEN/TC 122 “Ergonomics” the secretariat of
which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2020, and conflicting national standards
shall be withdrawn at the latest by December 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 9241-110:2006.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 9241-110:2020 has been approved by CEN as EN ISO 9241-110:2020 without any
modification.
INTERNATIONAL ISO
STANDARD 9241-110
Second edition
2020-05
Ergonomics of human-system
interaction —
Part 110:
Interaction principles
Ergonomie de l'interaction homme-système —
Partie 110: Principes d’interaction
Reference number
ISO 9241-110:2020(E)
©
ISO 2020
ISO 9241-110:2020(E)
© ISO 2020
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
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below or ISO’s member body in the country of the requester.
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Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 9241-110:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Interaction principles . 4
4.1 Overview . 4
4.2 Coverage of this set of interaction principles and general design recommendations. 5
4.3 Use of the interaction principles in human-centred design . 5
4.4 Contribution of the interaction principles to usability . 6
4.5 Relationships between interaction principles . 6
4.6 Framework for using this document . 6
5 Principles and recommendations . 8
5.1 Suitability for the user’s tasks . 8
5.1.1 Principle . 8
5.1.2 Recommendations related to identifying suitability of the interactive
system for a given task . . 9
5.1.3 Recommendations related to optimizing effort in task accomplishment . 9
5.1.4 Recommendations related to defaults supporting the task . 9
5.2 Self-descriptiveness .10
5.2.1 Principle .10
5.2.2 Recommendations related to presence and obviousness of the information .10
5.2.3 Recommendations related to clear indication of processing status .11
5.3 Conformity with user expectations .11
5.3.1 Principle .11
5.3.2 Recommendations related to appropriate system behaviour and responses .12
5.3.3 Recommendations related to consistency (internal and external) .13
5.3.4 Recommendations related to changes in the context of use .13
5.4 Learnability .14
5.4.1 Principle .14
5.4.2 Recommendations related to discovery .14
5.4.3 Recommendations related to exploration.15
5.4.4 Recommendations related to retention .15
5.5 Controllability .15
5.5.1 Principle .15
5.5.2 Recommendations related to interruption by the user .16
5.5.3 Recommendations related to flexibility .16
5.5.4 Recommendations related to individualization .17
5.6 Use error robustness .18
5.6.1 Principle .18
5.6.2 Recommendations related to use error avoidance .18
5.6.3 Recommendations related to use error tolerance .19
5.6.4 Recommendations related to use error recovery .19
5.7 User engagement .20
5.7.1 Principle .20
5.7.2 Recommendations related to motivating the user to use the system .21
5.7.3 Recommendations related to trustworthiness of the system .22
5.7.4 Recommendations related to increasing user involvement with the system .23
Annex A (informative) Checklist to aid in applying the recommendations in this document .24
Bibliography .31
ISO 9241-110:2020(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
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 ISO documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO 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).
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.
This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 4,
Ergonomics of human-system interaction.
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.
This second edition cancels and replaces the first edition (ISO 9241-110:2006), which has been
substantially technically revised.
The main changes compared to the previous edition are as follows:
— the principle of individualization has been merged into the principle of controllability;
— a new principle on user engagement has been developed;
— existing principles and general design recommendations have been revised.
A list of all parts in the ISO 9241 series can be found on the ISO website.
iv © ISO 2020 – All rights reserved

ISO 9241-110:2020(E)
Introduction
This document describes interaction principles (formerly referred to as "dialogue principles") and
general design recommendations which are independent of any specific interaction technique and
which are applicable in the analysis, design and evaluation of interactive systems.
This document significantly revises and updates the first edition. It incorporates relevant guidance
previously contained in ISO 14915-1. The general design recommendations in this document are derived
from a combination of ergonomics research and various sources of general and heuristic guidance
[16] [19] [23] [24] [29]
(including Bastien , Dzida , Molich , Nielsen and Tognazzini ).
These interaction principles and general design recommendations can guide the development and
evaluation of user interfaces, leading to improved usability.
The priority with which each interaction principle or general design recommendation is applied depends
on the purpose of the interactive system, the characteristics of the intended and foreseeable users of
the system, the tasks, the environment, the specific interaction technique used and the consequences
arising from use. Guidance on identifying relevant aspects of the users, tasks and environment of use is
given in ISO 9241-11.
The ultimate beneficiary of this document will be the user of an interactive system. Although it is
unlikely that the user will read this document or even know of its existence, its application by the
developers of the interactive system will lead to user interfaces which are more usable, accessible,
consistent and that enable greater productivity and a more positive user experience, and which avoid
harm from use. The benefits for suppliers of interactive systems include increased sales, customer
satisfaction and loyalty, decreased costs of providing service.
Applying these interaction principles and the associated general design recommendations also helps
prevent users of those products from experiencing usability problems such as:
— additional unnecessary steps not required as part of the task;
— misleading information;
— insufficient and poor information on the user interface;
— unexpected responses of the interactive system (including those leading to harm from use);
— navigational limitations during use; and
— inefficient error recovery.
This document comprises the following:
a) a framework for applying the interaction principles and general design recommendations;
b) the interaction principles;
c) general design recommendations corresponding to the interaction principles.
INTERNATIONAL STANDARD ISO 9241-110:2020(E)
Ergonomics of human-system interaction —
Part 110:
Interaction principles
1 Scope
This document describes principles for interaction between a user and a system that are formulated
in general terms (i.e. independent of situations of use, application, environment or technology). This
document provides a framework for applying those interaction principles and the general design
recommendations for interactive systems.
While this document is applicable to all types of interactive systems, it does not cover the specifics
of every application domain (e.g. safety critical systems, collaborative work, artificial intelligence
features).
It is intended for the following audiences:
— analysts of requirements (including market requirements, user requirements, and system
requirements);
— designers of user interface development tools and style guides to be used by user interface designers
and developers;
— designers of user interfaces who will apply the guidance during the design activities (either directly,
based on training, or by using tools and style guides which incorporate the guidance);
— developers who will apply the guidance during the development process;
— evaluators who are responsible for ensuring that products meet the general design recommendations
contained in this document;
— buyers who will reference this document in contracts during product procurement.
This document focuses on interaction principles related to the design of interactions between user and
interactive system. ISO 9241-112 provides further guidance on the presentation of information.
This document does not consider any other aspect of design such as marketing, aesthetics and corporate
identity.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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 http:// www .electropedia .org/
ISO 9241-110:2020(E)
3.1
accessibility
extent to which products, systems, services, environments and facilities can be used by people from a
population with the widest range of user needs, characteristics and capabilities to achieve identified
goals in identified contexts of use
Note 1 to entry: Context of use includes direct use or use supported by assistive technologies.
[SOURCE: ISO 9241-112:2017, 3.15]
3.2
context of use
combination of users, goals and tasks, resources, and environment
Note 1 to entry: The “environment” in a context of use includes the technical, physical, social, cultural and
organizational environments.
[SOURCE: ISO 9241-11:2018, 3.1.15]
3.3
goal
intended outcome
[SOURCE: ISO 9241-11:2018, 3.1.10]
3.4
interactive system
combination of hardware and/or software and/or services and/or people that users interact with in
order to achieve specific goals
Note 1 to entry: This includes, where appropriate, packaging, user documentation, online and human help,
support and training.
Note 2 to entry: The term “system” is often used rather than “interactive system”.
[SOURCE: ISO 9241-11:2018, 3.1.5, modified — Note 2 to entry has been added.]
3.5
task
set of activities undertaken in order to achieve a specific goal
Note 1 to entry: These activities can be physical, perceptual and/or cognitive.
Note 2 to entry: While goals are independent of the means used to achieve them, tasks describe particular means
of achieving goals.
Note 3 to entry: The term “task” is used here, as in ISO 9241-11, in its widest sense, rather than in reference to the
specifics of use of the interactive system.
[SOURCE: ISO 9241-11:2018, 3.1.11, modified — Note 3 to entry has been added.]
3.6
usability
extent to which a system, product or service 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: The “specified” users, goals and context of use refer to the particular combination of users, goals
and context of use for which usability is being considered.
Note 2 to entry: The word “usability” is also used as a qualifier to refer to the design knowledge, competencies,
activities and design attributes that contribute to usability, such as usability expertise, usability professional,
usability engineering, usability method, usability evaluation, usability heuristic.
[SOURCE: ISO 9241-11:2018, 3.1.1]
2 © ISO 2020 – All rights reserved

ISO 9241-110:2020(E)
3.7
use error
user action or lack of user action while using the system, product or service that leads to a different
result than that intended by the manufacturer or expected by the user
Note 1 to entry: Use error includes the inability of the user to complete a task.
Note 2 to entry: Use errors can result from a mismatch between the characteristics of the user, user interface,
task, or use environment.
Note 3 to entry: Users might be aware or unaware that a use error has occurred.
Note 4 to entry: A malfunction of an interactive system that causes an unexpected result is not considered a
use error.
Note 5 to entry: The term use error is used in preference to user error or human error in order to avoid the
implied assignment of responsibility for the error to the user.
[SOURCE: ISO 9241-11:2018, 3.3.3]
3.8
user
person who interacts with the system, product or service
Note 1 to entry: Users of a system, product or service include people who operate the system, people who make
use of the output of the system and people who support the system (including providing maintenance and
training).
[SOURCE: ISO 9241-11:2018, 3.1.7]
3.9
user experience
combination of user’s perceptions and responses that result from the use and/or anticipated use of a
system, product or service
Note 1 to entry: Users’ perceptions and responses include the users’ emotions, beliefs, preferences, perceptions,
comfort, behaviours, and accomplishments that occur before, during and after use.
Note 2 to entry: User experience is a consequence of brand image, presentation, functionality, system
performance, interactive behaviour, and assistive capabilities of a system, product or service. It also results from
the user’s internal and physical state resulting from prior experiences, attitudes, skills, abilities and personality;
and from the context of use.
Note 3 to entry: The term “user experience” can also be used to refer to competence or processes such as user
experience professional, user experience design, user experience method, user experience evaluation, user
experience research, user experience department.
Note 4 to entry: Human-centred design can only manage those aspects of user experience that result from
designed aspects of the interactive system.
[SOURCE: ISO 9241-11:2018, 3.2.3]
3.10
user interface
set of all the components of an interactive system that provide information and controls for the user to
accomplish specific tasks with the interactive system
ISO 9241-110:2020(E)
3.11
user-system interaction
user interaction
exchange of information between a user and an interactive system via the user interface to complete
the intended task
Note 1 to entry: User-system interaction represents a subset of human-system interaction that only focusses on
intended users and not other humans who can be affected by the interactive system.
[SOURCE: ISO/IEC 25060:2010, 2.22, modified — Note 1 to entry has been added.]
4 Interaction principles
4.1 Overview
This clause introduces the interaction principles. Seven principles have been identified as being
important for the design and evaluation of interactive systems.
— Suitability for the user’s tasks: An interactive system is suitable for the user's tasks when it
supports the users in the completion of their tasks, i.e. when the operating functions and the user-
system interactions are based on the task characteristics (rather than the technology chosen to
perform the task).
— Self-descriptiveness: The interactive system presents appropriate information, where needed by
the user, to make its capabilities and use immediately obvious to the user without unnecessary
user-system interactions.
— Conformity with user expectations: The interactive system’s behaviour is predictable based on
the context of use and commonly accepted conventions in this context.
— Learnability: The interactive system supports discovery of its capabilities and how to use them,
allows exploration of the interactive system, minimizes the need for learning and provides support
when learning is needed.
— Controllability: The interactive system allows the user to maintain control of the user interface
and the interactions, including the speed and sequence and individualization of the user-system
interaction.
— Use error robustness: The interactive system assists the user in avoiding errors and in case of
identifiable errors treats them tolerantly and assists the user when recovering from errors.
— User engagement: The interactive system presents functions and information in an inviting and
motivating manner supporting continued interaction with the system.
NOTE The order in which the principles are presented here does not imply any priority.
For each of the principles, this document provides a list of general design recommendations. The
application of a single recommendation does not mean that the application of a principle has been fully
satisfied.
Table 1 identifies the main categories used to structure recommendations for each of the principles.
These recommendations help in the identification and specification of user requirements relevant to
specific contexts of use (see ISO 25065).
4 © ISO 2020 – All rights reserved

ISO 9241-110:2020(E)
Table 1 — Interaction principles and their main categories of recommendations
Interaction Principle Categories of recommendations
Suitability for the user’s tasks a) identifying suitability of the interactive system for a given task
b) optimizing effort in task accomplishment
c) defaults supporting the task
Self-descriptiveness a) presence and obviousness of the information
b) clear indication of processing status
Conformity with user expectations a) appropriate system behaviour and responses
b) consistency (internal and external)
c) changes in the context of use
Learnability a) discovery (of information and controls that users are looking for)
b) exploration (of information and controls that users have
discovered)
c) retention (of information about the system)
Controllability a) interruption by the user
b) flexibility
c) individualization
Use error robustness a) use error avoidance
b) use error tolerance
c) use error recovery
User engagement a) motivating the user
b) trustworthiness of the system
c) increasing user involvement with the system
4.2 Coverage of this set of interaction principles and general design recommendations
The principles and general design recommendations identified in this document are generic and are
not tied to any particular system or context of use. General design recommendations are organized
under the principles to which they appear to be most relevant. However, it is recognized that since the
principles can overlap, recommendations can relate to more than one principle. Each recommendation
is presented under only a single principle, since understanding and using the recommendations is more
important than categorizing them.
While the recommendations presented in this document summarize important guidance obtained from
current knowledge, it is possible that additional guidance will become important as technology and
ergonomics develop.
This document applies to most interactive systems in most contexts of use. It is up to individuals
using this document to determine any system and contexts of use where they do not apply. Not every
recommendation within this document is applicable in every context of use.
4.3 Use of the interaction principles in human-centred design
While this document describes product-related principles for interaction between users and interactive
systems, ISO 9241-210:2019 provides principles and guidance on activities of human-centred design for
interactive systems.
ISO 9241-110:2020(E)
4.4 Contribution of the interaction principles to usability
Usability is the extent to which a system, product or service can be used by specified users to achieve
specified goals with effectiveness, efficiency, and satisfaction in a specified context of use (see
ISO 9241-11). This recognizes that usability results from a complex set of factors and can be different
for different users, different goals and tasks, and different contexts of use.
Usability consists of effectiveness, efficiency and satisfaction, each of which is composed of more
specific components:
— effectiveness: the accuracy and completeness with which users achieve specified goals;
— efficiency: the resources used in relation to the results achieved;
— satisfaction: the extent to which the user's physical, cognitive and emotional responses that result
from the use of a system, product or service meet the user’s needs and expectations.
User-system interactions can affect each component. While some principles and some general design
recommendations appear to focus more on one component than the others, some principles and
recommendations affect all three components.
NOTE Suitability for the task addresses both effectiveness "to complete the task" and efficiency avoiding
"unnecessary steps and unnecessary information", while suitability for engagement primarily addresses
satisfaction.
4.5 Relationships between interaction principles
The interaction principles are not strictly independent and can semantically overlap. A usability
problem or a general design recommendation can relate to one or more interaction principles.
NOTE 1 If users do not detect some information because it is placed at a location where users do not
expect it, a usability problem occurs because the interactive system does not conform with user expectations.
As a consequence, since the information is not present from the user’s perspective, when needed, the self-
descriptiveness of the interactive system is affected.
EXAMPLE 1 While creating a presentation, users use the undo function repeatedly to explore the look of
different styles. In this context, the undo function is used as a tool to achieve controllability. However, if users in
this situation use the undo function to explicitly correct an error, it is used to maintain use error robustness.
While the set of principles and general design recommendations are intended to optimize the usability
of the system, constraints can make it necessary to make “trade-offs” between the application of
principles in order to optimize usability. The applicability and the priority given to each principle varies
with the specific field of application, user groups and the interaction technique chosen.
NOTE 2 Examples for fields of application can range from work equipment over entertainment systems to
safety critical systems.
EXAMPLE 2 The limited display space on a smart watch leads to trade-offs between applying the interaction
principles. Because the display space is not sufficient to provide the information necessary for self-descriptiveness
a higher priority is assigned to achieving conformity with user expectations.
Each of the principles needs to be considered in analysis, design and evaluation. However, principles can
vary in their relative importance depending on the context of use and any constraints on the design. In
practice, within design situations for an interactive system, compromises are made.
4.6 Framework for using this document
This document provides interaction principles and general design recommendations for the interaction
between user and system that apply across application domains and particular technologies.
Annex A provides a checklist to aid in applying the general design recommendations in this document.
6 © ISO 2020 – All rights reserved

ISO 9241-110:2020(E)
ISO 9241-112 provides principles and general recommendations for the presentation of information
that apply across the three main modalities (visual, auditory, tactile/haptic) typically used in ICT. Those
principles and recommendations also apply across application domains and across technologies. The
principles of self-descriptiveness and conformity with user expectations are related to the presentation
of information. Information, which is not self-descriptive, can mislead the user.
Other ISO standards contain recommendations and requirements with a specific thematic focus:
— requirements and recommendations specific to the visual presentation of information are provided
in ISO 9241-125;
— requirements and recommendations specific to interaction techniques are provided in standards
such as ISO 9241-143;
— requirements and recommendations specific to an application domain are provided in standards
such as ISO 9241-154;
— requirements and recommendations specific to accessibility are provided in standards such as
ISO 9241-171.
Figure 1 illustrates the different levels of guidance contained in ISO standards for human-system
interaction. ISO standards related to human-system interaction contain guidance at the levels of:
— principles;
— general design recommendations;
— requirements and recommendations specific to a thematic subject.
They do not prescribe “standardized solutions” in terms of conventions (e.g. “the title bar of a window
in focus is coloured blue” or “the OK button is always placed left to the CANCEL button”). Such
“standardized conventions” are published by industry sources, in organizational style guides and can
be found in literature. However, the guidance relating to presented information in ISO standards related
to human-system interaction is intended to be applied when establishing or assessing standardized
conventions for user interfaces of interactive systems.
[The following serves as alternative text for Figure 1]
Figure 1 illustrates the relationship of major sources of guidance on user-system interaction. The
figure focuses on guidance from international standards, but also recognizes standardized conventions
not in scope of ISO standards. ISO 9241-11 introduces the concepts of usability, and its components
effectiveness, efficiency, and satisfaction and the concept of context of use. ISO/IEC 29138-1 identifies
the range of user accessibility needs. Two standards (this document, ISO 9241-110, Interaction
principles, and ISO 9241-112, Principles for the presentation of information) provide high-level guidance
for achieving usability. The interaction principles in this document include: suitability for the task, self-
descriptiveness, conformity with user expectations, learnability, controllability, use error robustness,
and user engagement. The ISO 9241-112 principles for the presentation of information include:
detectability, freedom from distraction, discriminability, unambiguous interpretability, conciseness,
and consistency (internal and external). Numerous other international standards (both within the
ISO 9241 series and beyond) provide specific guidance for human-system interaction, the presentation
of information, and accessibility. Some sources of specific guidance include: software standards
ISO 9241-13 and ISO 9241-14 and standards in the ISO 9241-100 series, hardware standards in the
ISO 9241-300 and ISO 9241-400 series, workplace and environmental standards in the ISO 9241-500
and ISO 9241-600 series, tactile/haptic standards in the ISO 9241-900 series, and other standards
outside the ISO 9241 series (such as ISO/IEC 62366-1). Examples of standardized conventions (not in
the scope of ISO standards) include: Microsoft Windows User Experience Guidelines and iOS Human
Interface Guidelines.
[End of alternative text]
ISO 9241-110:2020(E)
Figure 1 — The relationship of major sources of guidance for user-system interaction
5 Principles and recommendations
5.1 Suitability for the user’s tasks
5.1.1 Principle
An interactive system is suitable for the user's tasks when it supports the users in the completion of
their tasks, i.e. when the operating functions and the user-system interactions are based on the task
characteristics (rather than the technology chosen to perform the task).
NOTE 1 A prerequisite for suitability for the user’s tasks is that the tasks themselves have been based on
user needs.
NOTE 2 It is important that user-system interactions are based on the task characteristics, rather than the
technology chosen to perform the task.
Suitability for the user's tasks involves guidance related to:
a) identifying suitability of the interactive system for a given task;
b) optimizing effort in task accomplishment;
c) defaults supporting the task.
8 © ISO 2020 – All rights reserved

ISO 9241-110:2020(E)
5.1.2 Recommendations related to identifying suitability of the interactive system for a
given task
The interactive system should provide sufficient information to enable the users to determine whether
the system is appropriate for their intended outcomes.
EXAMPLE 1 The start page of a navigation app concisely identifies the tasks that it supports.
EXAMPLE 2 A parking ticket machine clearly indicates which credit cards it accepts.
5.1.3 Recommendations related to optimizing effort in task accomplishment
5.1.3.1 The interactive system should provide the user with the controls and task-related information
needed for each step of the task.
EXAMPLE 1 A check-in system for flights indicates that a seat can be chosen before the check in process is
completed.
NOTE The user needs related to the task determine the required quality, quantity and type of information to
be presented.
EXAMPLE 2 A ticket machine for train tickets offers a function for imputing the desired destination and
displays the price based on the input.
5.1.3.2 The interactive system should avoid imposing steps on the user that are derived from the
technology rather than from the needs of the task itself.
NOTE 1 Structuring interaction based on the system's internal data model or internal processing steps can
cause unnecessary learning burdens on the user.
EXAMPLE 1 A software application for compressing the size of a file allows the user to first select one or more
files to be compressed and then allows the user to compress the file size of all selected files instead of asking the
user to first “create an archive” for the files to be compressed.
EXAMPLE 2 A car has an automatic transmission rather than a manual transmission.
NOTE 2 Unnecessary steps include actions assigned to the user that can be more appropriately done
automatically by the system.
5.1.3.3 The interactive system should avoid offering functionality to the user and presenting
information that interferes with completing current tasks.
EXAMPLE 1 A hotel booking system displays only hotels with available rooms for a specific date selected by
the user. Information about other hotels in the area is not presented.
EXAMPLE 2 A traffic information display on the street only displays information, if relevant traffic information
is present and does not display anything in case there is no traffic information, instead of stating “No traffic
information available” which distracts the driver from driving.
NOTE The presentation of inappropriate information can lead to decreased task performance and
unnecessary mental workload.
5.1.4 Recommendations related to defaults supporting the task
5.1.4.1 The interactive system should offer defaults, where appropriate.
NOTE Default values can include standard values, values based on the current context, and values that
reflect previous use of the system by the current user.
EXAMPLE 1 A ticket machine at a railway station provides its location as the default station of departure.
ISO 9241-110:2020(E)
EXAMPLE 2 When a user returns to an e-commerce site, the system suggests the last product
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