07 norms and standards

www.dadda.it roberto@dadda.it Excellence in usability 1st semester 2021-2022 1
ERGONOMICS APPLIED TO THE DESIGN OF USABLE WEB
PAGES AND APPS
Roberto DADDA and Paolo NEGRI

Usability
Principles & guidelines

… before breaking them!
Innovation comes from knoledge of past

Different rules
Principles Standards
Guidelines
Design
rules
Hight generality
Low generality
Low
coercivenesses
Hight
coercivenesses

Terms and definitions
Principles
General principles for the design of usable user interfaces, based on scientific evidence or general consensus.
Derived from knowledge of the psychological, computational, and social aspects and are independent of the
technology. They are often expressed in a very general form.
Guidelines
Set of recommendations for the design of the user interface for a particular class of systems, expressed in a
general way but less abstract than standards, with examples and motivations. They are not binding, it’s up to the
designer to decide whether to apply them to a scenario.
Standards
Set of rules to be applied in the design of a class of systems. They are binding: designers must apply them. They
are usually issued by a institute of standardization. It must be possible to accurately assess compliance with
standards.
Design Rules
Set of rules to be applied in the design of a particular system. They are binding,

Different rules
Guidelines
Design
rules
Hight generality
Low generality
Low
coercivenesses
Hight
coercivenesses

Usability Standards
• Complex situation: the standards are evolving continuously
(www.iso.org ; www.uninfo.it)
• The process is very slow, and passes through several stages
• There are standards of product and standards of process

ISO 9241:
Ergonomics of human system interaction
It’s a standard consisting of the following series (each
consisting of different documents), and in different stages of
evolution (currently about twenty documents) belonging to
the following series:
100 series: Software ergonomics
200 series: Human system interaction processes
300 series: Displays and display related hardware
400 series: Physical input devices – ergonomics principles
500 series: Workplace ergonomics
600 series: Environment ergonomics
700 series: Application domains - Control rooms
900 series: Tactile and haptic interactions
ἴσος
Equal, similar

ISO 9241 documents
Part 1: General introduction
Part 2: Guidance on task requirements
Part 4: Keyboard requirements
Part 5: Workstation layout and postural requirements
Part 6: Guidance on the work environment
Part 9: Requirements for non-keyboard input devices
Part 11: Guidance on usability
Part 12: Presentation of information
Part 13: User guidance
Part 14: Menu dialogues
Part 15: Command dialogues
Part 16: Direct manipulation dialogues
Part 17: Form filling dialogues
Part 20: Accessibility guidelines for ICT equipment and services
Part 100: Introduction to standards related to software ergonomics
Part 110: Dialogue principles
Part 129: (DIS) Guidance on software individualization
Part 151: Guidance on World Wide Web user interfaces
Part 171: Guidance on software accessibility
Part 210: Human-centred design for interactive systems
Part 300: Introduction to electronic visual display requirements
Part 302: Terminology for electronic visual displays
Part 303: Requirements for electronic visual displays
Part 304: User performance test methods for electronic visual displays
Part 305: Optical laboratory test methods for electronic visual displays
Part 306: Field assessment methods for electronic visual displays
Part 307: Analysis and compliance test methods for electronic visual
displays
Part 308: Surface-conduction electron-emitter displays (SED)
Part 309: Organic light-emitting diode (OLED) displays
Part 400: Principles and requirements for physical input devices
Part 410: Design criteria for physical input devices
Part 420: (DIS) Selection procedures for physical input devices
Part 910: (DIS) Framework for tactile and haptic interaction
Part 920: Guidance on tactile and haptic interactions

Usability framework
The official ISO
9241-11 definition of
usability is: “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.”

Different rules
Guidelines
Design
rules
Hight generality
Low generality
Low
coercivenesses
Hight
coercivenesses

User interface design guidelines
Android:
http://developer.android.com/guide/topics/ui/index.html
iOS:
https://developer.apple.com/library/ios/documentation/use
rexperience/conceptual/MobileHIG/index.html

Different rules
Guidelines
Design
rules
Hight generality
Low generality
Low
coercivenesses
Hight
coercivenesses

Design patterns
A design pattern is a general solution to a design
problem that recurs in many situations, even very
different.
Not a “conclusive” solution, but rather a model, a
template to be adapted to the specific situation.
The concept originated in architecture at the end of the
70's (Christopher Alexander), and was applied to
software engineering from the late 80s.
illustration
of
Christopher
Alexander's
'Positive
Outdoor
Space'
by
Matt
Noiseux

Christopher Alexander (Vienna, 4 ottobre 1936)

Pattern in interface design

Mobile design patterns, examples
http://www.mobile-patterns.com
http://http://pttrns.com
http://inspired-ui.com (iPhone)
http://www.sitepoint.com/examples-mobile-design-patterns/
A book:
http://www.mobiledesignpatterngallery.com

Patterns: how and why?
The formalism of description
are different, but normally each
pattern is described in a sheet
providing:
• the problem in question
• the pattern that solves the
problem
• The motivations
• The scope/limitations of
application
• Examples of use
ADVANTAGES
• Suggest solutions to designers
• Creation of a common language
• Spread the "de facto standard"
• Avoid "reinventing the wheel"

Different rules
Guidelines
Design
rules
Hight generality
Low generality
Low
coercivenesses
Hight
coercivenesses

Principles
• The "moral principles" are the principles
driving the "good" human behavior.
• In system design, we can seek those "moral
principles" that should guide us, especially
when we have to choose between different
solutions.
• Are all the more valid as practice shows that
derogate from these principles creates,
sooner or later, difficulties.

9241-110: 7 principles
It deals 7 principles about the dialogue
between humans and information
systems:
1. Suitability for the task
2. Self descriptiveness
3. Conformity with user expectations
4. Suitability for learning
5. Controllability
6. Error tolerance
7. Suitability for individualization

7 dialogue principles in ISO 9241-110:2006
5. Controllability
6. Error tolerance
system functionality and
dialogue are based on the
characteristics of the task,
rather than the technology
chosen to solve it

Suitability for the task: how
This principle is declined as…
... "spasmodic" attention to the identification of
the use cases, and the definition of the use
case diagram, document-level requirements in
order to guide the design; also…
...the definition of typical usage scenarios
helped us to refine the analysis

Suitability for the task: aspects
Phases of interaction adequate to the task
Information and formats adequate to the task
I/O devices adequate to the task
Interaction techniques adequate to the task
Typical Defaults
But...
Essential dialogue (no unnecessary redundancy for the task)

Demarcation of phases (fencing)

Do not overload the STM

Essential dialogue
Thoroughly analyze the
redundancies:
Are they needed?
What are they needed for?
Who needs them?
Are there any disadvantages
in eliminating them?

5. Controllability
6. Error tolerance
It is clear to users, at all times, in
which dialogue they are, where
they are in the dialogue, which
actions they can do and how
these can be made

Avoid the Vincent Flanders
Mystery meat navigation aka MMN

3. Conformity with user
expectations
5. Controllability
6. Error tolerance
The dialogue corresponds to the
user's needs, predictable
because of the context and
commonly accepted conventions

The words “conformity with user
expectations" is very general,
and it includes many particular aspects,
including the "coherence" between the
various aspects of interaction.
Adherence to this design principle must
be very, very carefully analyzed

Conformity with user expectations
implemented
This principle is about:
...examining used terms and phrases carefully
...using the same pattern of interaction in all phases of the
application (consistency)
...following the guidelines of the particular device used
...using fonts, graphic shapes and colors in a consistent way
throughout the application

Adhere to the conventions

1 2
3
1. PowerPoint 2007
2. Word 2007
3. Excel 2007

5. Controllability
6. Error tolerance
Dialogue supports and guides
you in learning the system

User evolves, the system must evolve with him
All
users
are
…
Newbee
Most
of
them
will
be…
Goog users
Some
of
them
will
become…
Competent
Few
of
them
will
become
Experts

Suitability for learning: aspects
• Aided familiarization
• Low threshold of learning
• Intermediate feedback
• Guaranteed and secure test
• Evident conceptual model
• Facilitated re-learning

Help online: help types
• What it this and what is its purpose?
• Where is this command?
• Explain this topic?
• How do I accomplish this?

5. Controllability
6. Error tolerance
The user is able to begin and
keep under control the direction
and timing of the interaction up
to achieving the objective

Controllability, implemented
This principle is about:
..."spasmodic" attention to navigation fluidity (back
command always present, home page as "safe haven")
...eliminating phases of dialogue that can be done only
once, at its beginning only (!)
...eliminating Q & A controlled by the system

5. Controllability
6. Error tolerance
Despite obvious errors in the
input, the desired results can be
achieved with little or no
corrective action

Error tolerance: aspects
• User help
• Prevention of illicit actions
• Explanation of the error
• Error recovery
• Automatic corrections
• Possibility of deferred correction
• Additional explanations
• Verification and validation of data
• Minimum correction effort
• Confirmation requests

5. Controllability
6. Error tolerance
7. Suitability for
individualization
The user can change the
interaction and presentation of
information to suit his personal
needs and individual skills

Suitability for individualization: aspects
• Adaptation to the user's profile
• Choice of alternative representations
• Choice of the level of explanations
• Customizable vocabulary
• Customizable response times
• Choice of the method of interaction
• Customizable dialogue
• Versioning and recoverability of previous values

Meaning that users can adapt the product to their own
needs. For example, a beginner has different expectations
of a product than an expert.

Alternative representations

Customizable vocabulary

Wizard versus Fast track

Another point of view of the same
concepts
10 Usability Heuristics for User Interface Design
By Jakob Nielsen
1. Visibility of system status
2. Match between system and the real world
3. User control and freedom
4. Consistency and standards
5. Error prevention
6. Recognition rather than recall
7. Flexibility and efficiency of use
8. Aesthetic and minimalist design
9. Help users recognize, diagnose, and recover from errors
10. Help and documentation
(J.Nielsen, How to conduct a Heuristi Evaluation, in
http://www.useit.com/papers/heuristic/heuristic_evaluation.html )

07 norms and standards

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