Users and User Characteristics

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Users and User Characteristics
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Contents

• Users - Designing for diversity
• Characteristics of users

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Recap - Scope of HCI

• Designing usable systems requires us to have
  knowledge of
• The users who will use the system.
• The tasks for which it will be used.
• The environment in which it will be used.
• So designers need knowledge of
• The physiological and psychological capabilities
  of the user.
• The types of tasks that users will be expected to
  carry out.
• The organisational and environmental aspects of
  the users task.
• The technical constraints of the system.

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Designing for Diversity

• The wide range of human abilities, backgrounds,
  motivations, personalities and intelligence
  presents major challenges for interactive system
  designers.
• They need to have an understanding of
• physical characteristics
• cognitive and perceptual abilities
• personality differences
• general abilities
• These are all characteristics which apply to
  people in general, we shall also consider
  characteristics which apply specifically to
  potential system users.

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Differences between user groups

• Consider the design of a check-out system for a
  large supermarket and the design of a counter
  system for a high-street building society
• Talk to the person next to you and make a list of
  some of the differences between the groups of
  people who will use each system
• List also how these differences could affect
  design decisions about each system

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Physical Characteristics

• Think of a car and its interface (controls).
• What physical aspects need to be considered?
• Basic data about human dimensions comes from
  anthropometry.
• What is average?
• What compromises must be made?
• e.g. keyboard spacing, mouse size and shape.
• Adjustments to interface, e.g. brightness of
  VDUs.
• These aspects of the physical design of
  workstations is part of Ergonomics.

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User characteristics physical differences

• Age (use larger fonts for older people)
• Vision limitations, such as colour blindness
• Other physical limitations that might restrict
  movement (See Chapter 12)
• Small children dont have good fine-muscle
  control see big buttons on next slide

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Big buttons for little people
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Personality

• Many differences exist between individuals
  personalities
• Extroversion/Introversion
• Convergent/Divergent thinking
• Feeling/Thinking.
• Personality differences will affect how people
  interact with the system
• preferences for interaction styles,
• graphical or tabular representations,
• motivation towards the task.

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User characteristics cultural differences

• Language (how many languages should be supported)
• Education (reading level)
• Profession (specialized vocabularies)
• Attitude towards computer systems (e.g
  technophobia amongst elderly users)
• Corporate style what are you trying to convey to
  whom?

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System Related User Characteristics

• What characteristics can you expect of the users
  of your interface?
• frequency of use
• discretion to use the system
• knowledge of the task which the system will
  support
• knowledge of computers
• experience of other similar systems
• general abilities, e.g. literacy, vision
• attitude towards computers (and your system)
• existing skills (keyboard, mouse)

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High-fashion cosmetics have a style
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A bank site has a very different style
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Some Design Implications

• frequency of use amount of skill building that
  takes place and knowledge user can be expected to
  retain
• discretion to use the system impact of poor
  usability
• knowledge of the task which the system will
  support level of support at interface provided
  for how to complete tasks
• knowledge of computers level of guidance
  provided
• experience of other similar systems user
  expectations and use of familiar interface
  conventions
• general abilities, e.g. literacy, vision
  assumptions made about presentation of text,
  motor skills, intelligence
• attitude towards computers level of help and
  guidance and way in which system is introduced to
  users
• existing skills (keyboard, mouse) choice of
  interaction style to use to exploit existing
  skills

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Categorisation of Users

• There are a number of ways to categorise users
• Primary Secondary Users
• 3 D framework
• task knowledge/expertise
• computer knowledge/expertise
• Frequency of use
• Occupational categories
• Simple classification

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Primary and secondary users

• Primary (direct ) user the person who actively
  uses the site
• Airline reservation clerk
• Help desk staff
• Secondary (indirect) user the person being
  served by a primary user
• Airline passenger
• Customer who called the support line

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Three-Dimensional Framework
(high)
Knowledge of Computers
(high)
Frequency of Use
Knowledge of Task
(low)
(high)

• Three Dimensional Framework for User
  Classification

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Occupational Categorisation of Users

• Broad occupational classification as
• computer professionals
• professionals without computer experience
• skilled clerks
• naïve users
• special groups
• Remember the first four of these are broad
  classifications - make sure you understand your
  particular user group(s).

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Computer professionals

• Classification
• computer knowledge - high/very high
• task knowledge - high
• frequency of use - high
• Understand software and hardware.
• Intelligent, well-educated and highly motivated
  (often).
• May want to customise software for own needs.
• Have little patience, like rapid response in
  software.
• Sensitive to shortcomings in software.
• NOT typical of the majority of users

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• Design implications
• Provide for high degree of sophistication in
  interface
• range of functions provided,
• flexibility to combine functions to provide new
  commands,
• possibilities to customise interface to own
  needs.
• Lower requirement for user support than with
  other user types.
• Can utilise programming languages and extensible
  command languages (e.g. macros and scripts).

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Professionals without computing experience

• Classification
• computer knowledge - low/moderate
• task knowledge - high
• frequency of use - varies, low-high
• Know little about computers.
• Often not interested in computers.
• Probably have not read any documentation.
• Lack patience.
• Have high expectations of performance.
• Intolerant of software errors.

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• Motivated to accomplish the job/task the system
  was designed to support.
• May be discretionary users of systems.
• High degree of usability is critical for this
  group.
• Design implications
• Important to support the user guessing or
  experimenting with how operations can be carried
  out at the interface. Consistency and a close
  match to the users task model is important.
• Frequency of use determines how much the user can
  be expected to learn short cuts and accelerators.
• User support provided by the interface is
  important.

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Skilled clerks

• Classification
• computer knowledge - low
• task knowledge - high
• frequency of use - high
• May use a machine several hours a day.
• Develop very strong user skills.
• Do not have a high degree of computer
  sophistication.
• Want rapid responses in software.
• Quickly grow impatient with features designed for
  less experienced users if these features slow
  them down.
• Usage is not usually discretionary.

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• Design implications
• Can anticipate significant learning of routine
  operations to take place, so can make use of
  abbreviations and codes for data input.
• Can expect strong user skills to be developed,
  such as keyboard skills.
• Error messages must be clear and provide specific
  guidance for recovery.
• Cannot expect users to develop deeper knowledge
  or understanding of the computer system without
  specific training.

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Naïve users

• Classification
• computer knowledge - very low
• task knowledge - varies, low - moderate
• frequency of use - assume low
• Know (nearly) nothing about computers.
• Cannot assume significant learning process, i.e.
  each interaction with the system should be
  treated as if it were the users first.
• May feel intimidated by using a computer.
• Ease of learning is important usability
  criterion.
• Use of system is usually discretionary.

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• Design implications
• Every type of user error must be trapped. This
  type of user will not be able to infer what is
  happening or the cause of an error condition.
• Require explicit on-screen prompts for each step
  of the dialogue.
• High degree of user support and a low degree of
  sophistication is required in the interface.

?
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Special groups

• Do not make assumptions that the users of your
  interface/system fall into neat categories.
• Consider in particular design for sensory
  impairments.
• Techniques exist for analysing the
  characteristics of users in detail, e.g. the
  HUFIT (Human Factors in Information Technology)
  Toolset.

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Types of Knowledge

• Syntactic (computer) knowledge - knowledge of
  low-level mechanisms required to achieve a
  particular state.
• key bindings - e.g. Control Z end of file in
  DOS
• command line switches - e.g. ls -al in UNIX
• commands - e.g. Alt F S to save a file in many
  Windows applications
• Semantic (computer) knowledge about concepts or
  entities associated with the computer system.
• e.g. organisation of the file system, access
  rights to files.
• Semantic (task) knowledge about concepts or
  entities associated with the task to be
  performed.
• e.g. parts of a car design in CAD, or data
  requirements in statistics.

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Simple categorisation of users

• Novice users
• no syntactic knowledge, little semantic knowledge
• may have little task knowledge
• may have anxieties about computer use

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Simple categorisation of users

• Knowledgeable intermittent users
• can maintain semantic knowledge of task and
  computer concepts
• requirements for consistency of structures in
  interaction so that user inferences are supported
• good help facilities and documentation are
  required

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Simple categorisation of users

• Frequent users
• well trained in semantic and syntactic aspects
• rapid response time
• brief feedback
• abbreviated command sequences
• accelerators to move through dialogue sequences