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ISDE 2011
Users and User Characteristics
ISDE 2011
Contents
Users - Designing for diversity Characteristics of users
ISDE 2011
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
user’s task. The technical constraints of the system.
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Users!
Who are the users? What do we need to know and find
out about users? What ‘user characteristics’ are
important in interface design?
Users
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More Users !
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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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User Characteristics relevant to UI Design
Physical abilities & disabilities Pesonality Age – Sex – Culture Education Computer/IT knowledge Motivation Attitude
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Physical Characteristics - Activity Think of a car and its interface (controls).
What physical aspects need to be considered?
Height of users – seat height Arm and Leg Length - position of controls Feet Size – Width & Space between pedals Vision – Size of text/labels on instruments controls audio
equipment etc Hearing – volume/pitch of audio signals – indicators, seat belt
low fuel
User Characteristics 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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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.
Dr Phil
Who are you!!!
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Example – Sat Nav
User preferences for Voice – Male v Female - accents How information is presented – map v list
of directions How frequently reassured about being on
course/correct route Eg Cautious/timid type - frequently
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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 Small children don’t have good fine-muscle
control: see big buttons on next slide
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Big buttons for little people
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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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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
If designing an interface need to be able to categorise users
Easier for small systems much more difficult for large systems Primary or secondary user 3 D framework
task expertise computer expertise frequency of use
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Differences between user groups… Consider the design of an on-line hotel
reservation system for a multi-national hotel chain
Talk to the person next to you and make a list of some of the differences between the groups of people who will use the system
Identify who are the ‘stakeholders’ of this system
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Differences – Some Examples
Frequency of use Cultural Motivation Computer Knowledge/skills Experience of other hotel systems General ability – literacy education Physical differences
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Primary and secondary users
Primary user: the person who actively uses the site: Airline reservation clerk Help desk staff
Secondary user: the person being served by a primary user: Airline passenger Customer who called the support line
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Three-Dimensional Framework
Three Dimensional Framework for User Classification
Kno
wle
dge
of C
ompu
ters
Knowledge of Task
Frequency of Use
(low) (high)
(high)
(high)
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3 D framework applied to 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 user’s 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 user’s 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 users with Sensory impairments – partially sighted – colour blind -
deaf Physical impairments – lack of mobility – arthritis
Techniques exist for analysing the characteristics of users in detail
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Assumed knowledge: about computers
How much knowledge do you assume the user group has about computers in general?
Can you assume familiarity with graphical user interfaces (GUIs) – if not, don’t expect the user to know what a combo box and how to use it
Can you assume familiarity with using the internet –if so, you can assume familiarity with conventions and common facilities, and with using GUIs
Important particularly when designing for the (older) general public
Increasing public awareness of internet and computer use (but this can’t be taken for granted yet- 2009 still approx 10 million never or seldom used!)
