SIST EN ISO 14915-3:2003

SLOVENSKI STANDARD
01-marec-2003
Ergonomija programske opreme multimedijskih uporabniških vmesnikov - 3. del:
Izbira medijev in kombiniranje (ISO 14915-3:2002)
Software ergonomics for multimedia user interfaces - Part 3: Media selection and
combination (ISO 14915-3:2002)
Software-Ergonomie für Multimedia-Benutzerschnittstellen - Teil 3: Auswahl und
Kombination von Medien (ISO 14915-3:2002)
Ergonomie des logiciels pour les interfaces utilisateur multimédias - Partie 3: Sélection et
combinaison des médias (ISO 14915-3:2002
Ta slovenski standard je istoveten z: EN ISO 14915-3:2002
ICS:
13.180 Ergonomija Ergonomics
35.200 Vmesniška in povezovalna Interface and interconnection
oprema equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 14915-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2002
ICS 13.180; 35.200
English version
Software ergonomics for multimedia user interfaces - Part 3:
Media selection and combination (ISO 14915-3:2002)
Ergonomie des logiciels pour les interfaces utilisateur Software-Ergonomie für Multimedia-Benutzerschnittstellen -
multimédias - Partie 3: Sélection et combinaison des Teil 3: Auswahl und Kombination von Medien (ISO 14915-
médias (ISO 14915-3:2002) 3:2002)
This European Standard was approved by CEN on 10 October 2002.
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 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2002 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14915-3:2002 E
worldwide for CEN national Members.

CORRECTED  2003-02-05
Foreword
This document (ISO 14915-3:2002) 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 April 2003, and conflicting national
standards shall be withdrawn at the latest by April 2003.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg,
Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 14915-3:2002 has been approved by CEN as EN ISO 14915-3:2002 without any
modifications.
NOTE Normative references to International Standards are listed in Annex ZA (normative).
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of
any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications, indicated
by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 14915-1 2002 Software ergonomics for EN ISO 14915-1 2002
multimedia user interfaces - Part 1:
Design principles and framework
INTERNATIONAL ISO
STANDARD 14915-3
First edition
2002-10-15
Software ergonomics for multimedia user
interfaces —
Part 3:
Media selection and combination
Ergonomie des logiciels pour les interfaces utilisateur multimédias —
Partie 3: Sélection et combinaison des médias

Reference number
ISO 14915-3:2002(E)
©
ISO 2002
ISO 14915-3:2002(E)
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ii © ISO 2002 – All rights reserved

ISO 14915-3:2002(E)
Contents Page
Foreword . v
Introduction. vi
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 2
4 Application of this part of ISO 14915 . 6
4.1 Intended user groups. 6
4.2 Applying the recommendations . 6
4.3 Reporting conformance to this part of ISO 14915 . 6
5 General guidelines for media selection and combination . 6
5.1 General . 6
5.2 Supporting user tasks . 6
5.3 Supporting communication goals . 7
5.4 Ensuring compatibility with the users’ understanding. 7
5.5 Selecting media appropriate for the users’ characteristics.7
5.6 Supporting users’ preferences . 7
5.7 Considering the context of use . 7
5.8 Using redundancy for critical information. 8
5.9 Avoiding conflicting perceptual channels. 8
5.10 Avoiding semantic conflicts. 8
5.11 Designing for simplicity. 8
5.12 Combining media for different viewpoints . 8
5.13 Choosing media combinations to elaborate information . 8
5.14 Guarding against degradation . 9
5.15 Previewing media selections . 9
5.16 Using static media for important messages. 9
6 Media selection for information types . 9
6.1 General . 9
6.2 Consider information types . 11
6.3 Consider multiple-information types . 11
6.4 Selecting and combining media . 11
6.4.1 Physical information. 11
6.4.2 Conceptual information. 11
6.4.3 Descriptive information . 11
6.4.4 Spatial information. 11
6.4.5 Value information . 12
6.4.6 Relationship information. 12
6.4.7 Discrete action information. 12
6.4.8 Continuous action information. 12
6.4.9 Event information. 12
6.4.10 State information. 12
6.4.11 Causal information. 13
6.4.12 Procedural information. 13
7 Media integration. 13
7.1 General . 13
7.2 Design issues . 13
7.3 Media integration guidelines. 13
7.3.1 General . 13
ISO 14915-3:2002(E)
7.3.2 Advance organizers . 14
7.3.3 Synchronized, related media. 14
7.3.4 Separating audio content sources . 14
7.3.5 Avoiding interference in audio media . 14
7.3.6 Limiting speech interruptions in audio and language-based media . 14
7.3.7 Integrating non-realistic images with realistic images . 14
7.3.8 Use of captions with images . 14
8 Directing users’ attention . 15
8.1 General . 15
8.2 Direct-contact points for key thematic links . 15
8.3 Direct-contact points for linked components. 15
8.4 Indirect-contact points. 16
8.5 Sequence of contact points to connect a thread of topics. 16
8.6 Guidelines for contact points between media pairs. 16
8.6.1 General . 16
8.6.2 Source medium: realistic audio. 18
8.6.3 Source medium: non-realistic audio . 18
8.6.4 Source medium: speech. 19
8.6.5 Source medium: still image. 20
8.6.6 Source medium: text. 21
8.6.7 Source medium: moving image. 22
Annex A (informative) Decision trees for classification of types. 23
Annex B (informative) Guidelines for media-combination pairs. 27
Annex C (informative) Examples of media-combination patterns . 37
Annex D (informative) Design issues and cognitive background . 39
Bibliography. 42

iv © ISO 2002 – All rights reserved

ISO 14915-3:2002(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
The main task of technical committees is to prepare International Standards. Draft International Standards adopted
by the technical committees are circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this part of ISO 14915 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 14915-3 was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 4, Ergonomics of
human-system interaction.
ISO 14915 consists of the following parts, under the general title Software ergonomics for multimedia user
interfaces:
 Part 1: Design principles and framework
 Part 2: Multimedia navigation and control
 Part 3: Media selection and combination
Annexes A to D of this part of ISO 14915 are for information only.
ISO 14915-3:2002(E)
Introduction
The design of user interfaces for multimedia applications typically involves a much wider range of design and
evaluation issues than that of conventional user interfaces based only in textual and graphical format. Many
different techniques and design options are available. Multimedia user interfaces incorporate, integrate and
synchronize different media (static media such as text, graphics, images, and dynamic media such as audio,
animation, video or other sensory modalities). Within each medium, further distinctions can be made. Graphics, for
instance, can be presented either in two- or three-dimensional format and audio can be further categorized
according to the level of sound quality or with respect to mono, stereo or surround sound.
Ergonomic design enhances the ability of users to operate multimedia applications effectively, efficiently and with
satisfaction (see ISO 9241-11). This can be achieved by careful design of multimedia applications with respect to
the tasks they are intended to fulfil (e.g. for work, education or performance support), user characteristics and the
environment in which the system will be used. Multimedia applications are often used for communicative purposes.
An ergonomic design of multimedia user interfaces can also improve the safety of operating a system (e.g.
delivering an alarm in both visual and auditory media).
The range of media available and the interaction of these media have a variety of perceptual, cognitive and other
ergonomic implications for the users of multimedia applications. Multimedia can potentially impose on users a high
perceptual load, structural and semantic complexity, or a large volume of information to be conveyed through the
system. Manipulation of data or information presented in multimedia applications is also often part of the user's
activity.
This part of ISO 14915 provides guidance on the selection, combination and integration of media. The focus is
primarily on presentational aspects of multimedia (i.e. from system to user) as opposed to control and navigation
issues, which are addressed in ISO 14915-2. This part of ISO 14915 starts from information requirements, which
are stated in logical terms, and addresses the design issues concerning which media combinations to choose for
the information requirements. This is followed by guidance on how the user’s reading/viewing sequence can be
directed by design effects to ensure that the user acquires the desired information. Supplementary design guidance
for different media combinations and integration are presented in informative annexes A to D.
vi © ISO 2002 – All rights reserved

INTERNATIONAL STANDARD ISO 14915-3:2002(E)

Software ergonomics for multimedia user interfaces —
Part 3:
Media selection and combination
1 Scope
This part of ISO 14915 gives recommendations for, and guidance on, the design, selection and combination of
interactive user interfaces that integrate and synchronize different media. It addresses user interfaces for
applications that incorporate, integrate and synchronize different media. This includes static media such as text,
graphics, images; and dynamic media such as audio, animation, video or media related to other sensory
modalities. Detailed design issues within a single medium (e.g. the graphical design of an animation sequence) are
only addressed as far as they imply ergonomic consequences for the user.
This part of ISO 14915 applies to
 presentational techniques for computer-based multimedia applications in general, including stand-alone and
networked applications when the prime goal is to support the user’s work task or provision of information,
 the design of the software user interface, and
 training and tutorial multimedia insofar as its recommendations bear on effective delivery of information.
This part of ISO 14915 does not deal with pedagogical design issues for tutorial applications and does not address
hardware issues, such as input or output devices. The recommendations in this part do not specifically address
applications whose primary purpose is entertainment, such as games. The focus of this part of ISO 14915 is on
multimedia presentation issues; multimodal input which uses different media, such as speech, in combination with
pointing for entering information is not considered in the recommendations provided.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 14915. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 14915 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 14915-1:2002, Software ergonomics for multimedia user interfaces — Part 1: Design principles and framework
1)
ISO 14915-2:— Software ergonomics for multimedia user interfaces — Part 2: Multimedia navigation and control

1) To be published.
ISO 14915-3:2002(E)
3 Terms and definitions
For the purposes of this part of ISO 14915, the following terms and definitions apply.
3.1
medium, sing.
media, plur.
different specific forms of presenting information to the human user
EXAMPLES These include text, video, graphics, animation, audio.
[ISO 14915-1:2002]
3.2
multimedia
combinations of static and/or dynamic media which can be interactively controlled and simultaneously presented in
an application
EXAMPLES These include combinations of text and video, or audio and animation.
[ISO 14915-1:2002]
3.3
static medium
medium in which the presentation to the user does not change over time
EXAMPLES These include text and pictures.
NOTE Adapted from ISO 14915-1:2002.
3.4
dynamic medium
medium in which the presentation to the user changes according to time
EXAMPLES These include video, music, animation, simulations.
NOTE Adapted from ISO 14915-1:2002.
3.5
content
information to be communicated by means of a multimedia application from the originator to the user according to
certain communication goals
[ISO 14915-1:2002]
3.6
information type
media-neutral description of information categories that constitute the content and components
NOTE Information types can be used to specify a message to be delivered in a multimedia application. As with media
types, information types embed dimensions and categories. An approach to classifying information components with information
types is given in informative annex A, which provides a decision tree (Figure A.1) that focuses first on whether a component is
physical or conceptual, then whether it is static (not changing) or dynamic and finally the category for the information content.
3.6.1
causal information
information describing the cause and effect of an event, including a sequence of events that describe causation
EXAMPLES Heat causing a liquid to boil. Behaviour of an algorithm that results in the desired goal.
2 © ISO 2002 – All rights reserved

ISO 14915-3:2002(E)
3.6.2
conceptual information
facts, opinions or information about objects which do not have a physical existence
EXAMPLES Taxonomic classes of animals and plants. Opinions about politics.
3.6.3
continuous action information
information describing movement and other activity that is perceived to occur over a period of time
EXAMPLES Making a meal. Driving a car.
NOTE Continuous actions are normally described in the present continuous tense in English.
3.6.4
descriptive information
information which describes an object, entity, or agent
EXAMPLES Red apples, texture of stone.
NOTE This can include states and histories of objects.
3.6.5
discrete action information
information describing movement and other activity that is perceived to occur at a point in time
EXAMPLES Switching a computer on. Closing a door.
NOTE Discrete actions are a set of steps.
3.6.6
event information
information about a state change, message indicating the occurrence of an action or conveying a significant
change in the world
EXAMPLES Telephone rings. E-mail message arrives, is sent.
NOTE Events may emanate from the environment as well as from objects.
3.6.7
physical information
information about phenomena which have a concrete existence; objects, agents or scenes that have a physical
existence
EXAMPLES Chair, table, landscape.
3.6.8
procedural information
information about a sequence of actions organized to achieve a goal or task
EXAMPLE Instructions to assemble a bookshelf from ready-made components.
3.6.9
relationship information
information about an association between objects or agents
EXAMPLES Seat and legs are part of a chair. A product is manufactured in a factory.
ISO 14915-3:2002(E)
3.6.10
spatial information
information about the spatial properties of the world, such as dimensions of structures, pathways, spatial
distribution, location
EXAMPLES Layout of furniture in a room. Directions to the metro station.
3.6.11
state information
properties of the environment, objects or agents that remain constant during a period of time
EXAMPLES The music is being played. A person is sleeping.
3.6.12
value information
quantitative information describing properties of an object
EXAMPLE Person’s height 1,80 m.
NOTE Relationships between many values may be shown by graphs and charts (see 3.6.9).
3.7
media type
categories of media that are used to present information to the user
NOTE Media types reflect the psychological properties of a medium as perceived by the user. Figure A.2 and the decision
tree (Figure A.3) in informative annex A help to classify media using the following definitions of media sub-types:
3.7.1
audio medium
any medium which can be heard (received by an audio channel)
EXAMPLES Dog barking, music, traffic noise, speech.
3.7.2
language-based medium
medium with content based on natural or formal languages
EXAMPLES Alphanumeric text. Spoken language. Symbols interpreted in language-based terms, such as hieroglyphics,
mathematical equations, and chemical formulae.
3.7.3
moving image medium
visual medium that is delivered at a rate that is judged by the human viewer to be a continuous image
EXAMPLES Video, film, animated diagrams, simulations.
NOTE For example, at a frame refresh rate above or near the flicker fusion frequency of 30 frames per second.
3.7.4
non-realistic medium
medium that is perceived by the user as not faithfully representing the natural world
EXAMPLES Diagrams, graphs, cartoons.
3.7.5
realistic medium
medium perceived by the user to faithfully represent the natural world
EXAMPLES Natural sounds. Photographic images. Film showing people and natural scenes.
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ISO 14915-3:2002(E)
NOTE Realistic media may be designed to create the illusion of the natural world, e.g. realistic animations of dinosaurs.
3.7.6
still-image medium
visual medium that is not presented continuously, although frames may be shown in a sequence either controlled
by the user or by the system with a time delay
EXAMPLES Photographs, drawings, graphs.
3.8
agent
person or machine which carries out actions and creates events
EXAMPLES User, designer, computer program.
3.9
concurrent media
two or more media that are juxtaposed/used simultaneously during a certain period when presented
EXAMPLE A voice-over describes action in a video.
3.10
direct contact point
thematic link between two media implemented with a designed effect in both the source and destination medium
EXAMPLE A text caption is linked by an arrow to an image component that is highlighted.
3.11
indirect contact point
thematic link between two media that is implemented with a designed effect only in the source medium
EXAMPLE The text refers to a diagram with the instruction “see Figure 1”.
3.12
media combination
sequential or concurrent combination of two or more media
EXAMPLES A video is presented in a window embedded in another window containing a still image. Speech introduces a
video which is then played.
3.13
sequential presentation
arrangement of two or more media that are represented one after another but do not overlap in time
EXAMPLE A video is shown, followed by a text summary.
3.14
thematic link
requirement to direct the users’ reading/viewing sequence between two media
NOTE For implementation, see contact points 3.10 and 3.11.
ISO 14915-3:2002(E)
4 Application of this part of ISO 14915
4.1 Intended user groups
The following groups are the intended users of this part of ISO 14915:
 user interface and multimedia designers who will apply this part of ISO 14915 during the development process;
 evaluators responsible for quality assurance who will ensure that products meet the recommendations of this
part of ISO 14915;
 potential buyers in selecting appropriately designed multimedia products;
 designers of multimedia development tools to be used by user interface and multimedia developers.
4.2 Applying the recommendations
The design guidelines provided in this part of ISO 14915 extend the principles described in ISO 14915-1.
Multimedia user interfaces should be designed according to both the principles of ISO 14915-1 and the guidelines
described in this part of ISO 14915. For certain contexts (e.g. certain tasks or user groups), the designer may be
forced to follow one guideline at the expense of another in order to achieve the optimal design.
4.3 Reporting conformance to this part of ISO 14915
If a claim of product or application conformity with this part of ISO 14915 is made, the procedure used in
establishing requirements for developing and/or evaluating the multimedia user interface shall be specified. The
level of specification of the procedure is a matter of negotiation between the involved parties. ISO 14915 is a multi-
part standard and therefore claims of conformity are related to the individual parts and not to the International
Standard as a whole.
5 General guidelines for media selection and combination
5.1 General
This clause contains general guidelines for media selection and combination followed by more specific guidelines
that map information types to appropriate media types for effective delivery. The principles in ISO 14915-1 provide
a basis for interpreting the following guidelines. Two or more media are considered combined if their presentation is
concurrent. Media are also considered to be combined or contiguous where the content is closely related or where
the media are explicitly grouped in a display in adjacent windows or displayed sequentially; for example, presenting
a picture followed by a text description.
Combining media can have advantages for the user. First, interfaces can be created that present information in a
way similar to the real world. Depending on the context of use, this can make users’ tasks easier, or more natural,
especially where features of the information match the users' experiences of the real world. For example, a picture
of a beach presented together with the sound of waves provides a better evocation of the subject than the picture
or the sound alone. Combining media can also help accommodate user preferences for information in a particular
format. For example, presenting text as well as pictures can accommodate users with a preference for either.
5.2 Supporting user tasks
Media should be selected and combined to support the user’s tasks.
EXAMPLE To compare two views, an architect's drawings with corresponding photographs showing the side and front
elevation of a building are placed side by side.
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ISO 14915-3:2002(E)
NOTE Some tasks benefit more from combination than others. If the task involves learning, or drawing attention to specific
information, the users can benefit from media combination that presents information redundantly. If, however, the task is
focused predominantly on one medium, for example visual inspection of diagrams, there can be considerably less benefit from
combination. The characteristics of the user’s task can also influence the sequence/concurrency of presentation; for instance, if
comparison is required, two images can be presented concurrently.
5.3 Supporting communication goals
Media should be selected to achieve the communication goal in the application.
EXAMPLES In an application that is critical for safety, the communication goal is to warn the users and protect them from
danger. In an aircraft emergency evacuation demonstration, speech is used for the instructions, with a diagram to show the
evacuation route.
5.4 Ensuring compatibility with the users’ understanding
Media should be selected to convey the content in a manner compatible with the user’s existing knowledge.
EXAMPLES A radiation symbol is used to convey danger to users who have the appropriate knowledge. An architectural
diagram is used to convey the structural layout of a building to architects and design engineers.
The user’s ability to understand the message conveyed by a particular medium should influence selection. This is
particularly important for non-realistic image media (diagrams, graphs) when interpretation is dependent on the
users' knowledge and culture.
5.5 Selecting media appropriate for the users’ characteristics
The characteristics of the user population should be considered when selecting media.
EXAMPLE Text is substituted by speech for blind users. Large point size text is accompanied by spoken representation of
the text for older users.
NOTE Users can be categorized as visualizers or verbalizers using psychologically based questionnaires. This information
can be used to aid selection of image- or language-based media.
5.6 Supporting users’ preferences
If appropriate to the task, users should be provided with alternative media from which they can select a preferred
medium or suppress certain media.
EXAMPLES The user chooses to display text captions on a picture rather than a speech commentary, or suppresses an
audio dialogue in a noisy environment. A blind user selects speech rather than text.
NOTE Some users can prefer to interact with systems using a particular medium. The abilities of the users and properties
of the users’ machine are important, so users may be given the option of low- or high-resolution graphics displays.
5.7 Considering the context of use
Selection and combination of media should be appropriate in the context of use.
EXAMPLES An inappropriate combination is the presentation of auditory as well as visual display of bank-account details
which could compromise the user’s privacy. A training video depicting an action accompanied by the speech “This is not correct”
could be missed if the speech is inaudible in a noisy environment.
NOTE Certain environments can impede accurate perception of information presented in a specific medium; for example,
an auditory warning might not be heard if it is presented in a noisy environment.
ISO 14915-3:2002(E)
5.8 Using redundancy for critical information
If important information is to be presented then the same subject matter should be presented in two or more media.
EXAMPLE Displaying an alarm-clock function visually as well as aurally. In a language-learning application, words are
spoken and displayed in text.
NOTE Effective redundant combinations present similar but not identical content on different media. Redundant
representation is useful for training and educational applications.
5.9 Avoiding conflicting perceptual channels
The same perceptual channel (e.g. hearing or vision) should not be used in concurrently presented dynamic media,
if the user needs to extract information from both media.
EXAMPLE Playing two or more videos with unrelated content is avoided because these will interfere with each other and
distract attention.
NOTE Concurrent presentation of two or more dynamic media makes it difficult for the user to perceive information from
each individual source unless the information is easy to integrate. Exceptions to this guideline occur in entertainment
applications, such as playing two unrelated videos in popular-music promotions.
5.10 Avoiding semantic conflicts
Presentation of conflicting information in any combination of media should be avoided.
EXAMPLE Avoid aural presentation of the word “Press the blue button” while the visual display shows a black and white
image.
NOTE Users cannot comprehend or gain an integrated understanding of conflicting information from different media,
especially in concurrent presentations.
5.11 Designing for simplicity
Minimal combination of media should be used to convey the information necessary for the user’s task.
EXAMPLE In a musical tutorial, the sound of music is combined with textual representation of the musical score. Adding a
video of a concert performance gives little extra information and distracts the user.
NOTE As the number of media used increases, the user’s effort required to attend to and process each medium also
increases, as does the effort in cross-referencing media. The trade-off between simplicity and more complex combinations will
depend on the user and task (see clause 5.2 and 5.3).
5.12 Combining media for different viewpoints
Wherever appropriate to the task, different views on the same subject matter should be provided by media
combination.
EXAMPLES Musical notation in a diagram gives the composer’s structural view of a symphony, speech commentary gives
the musician’s view of the structure, and music on the sound channel provides the aesthetic view. Two movies are played in
separate windows to show different viewpoints on the same scene, one showing a long-shot context of a football game, the
other a close up of a foul between two players in the long shot.
NOTE Presenting different views by media combination helps the user to assimilate information that is related to the same
topic or theme.
5.13 Choosing media combinations to elaborate information
Whenever appropriate to the task, media combinations should be selected to extend the information content.
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ISO 14915-3:2002(E)
EXAMPLE Showing a diagram of planets revolving around the sun with speech explaining forces of gravity and
momentum.
NOTE Media combination is used to add information to an existing topic, whereas combining media for different viewpoints
presents different aspects of the same topic.
5.14 Guarding against degradation
Technical constraints should be considered when selecting media delivery to avoid degraded quality or
unacceptable response times.
EXAMPLES To avoid delay in downloading a web page, moving images are segmented into storyboard stills and displayed
as a slide show. The display area of a moving image is reduced rather than slowing the frame rate. Simple images with lower
bandwidth requiremen
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