HFSD ISDE 2005

Users and User Characteristics

HFSD ISDE 2005

Contents

Users - Designing for diversity Characteristics of users

HFSD ISDE 2005

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.

HFSD ISDE 2005

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.

HFSD ISDE 2005

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

HFSD ISDE 2005

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.

HFSD ISDE 2005

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 don’t have good fine-muscle

control: see big buttons on next slide

HFSD ISDE 2005

Big buttons for little people

HFSD ISDE 2005

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.

HFSD ISDE 2005

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?

HFSD ISDE 2005

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)

HFSD ISDE 2005

High-fashion cosmetics have a style

HFSD ISDE 2005

A bank site has a very different style

HFSD ISDE 2005

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

HFSD ISDE 2005

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

HFSD ISDE 2005

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

HFSD ISDE 2005

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)

HFSD ISDE 2005

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).

HFSD ISDE 2005

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

HFSD ISDE 2005

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).

HFSD ISDE 2005

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.

HFSD ISDE 2005

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.

HFSD ISDE 2005

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.

HFSD ISDE 2005

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.

HFSD ISDE 2005

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.

HFSD ISDE 2005

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.

?

HFSD ISDE 2005

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.

HFSD ISDE 2005

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.

HFSD ISDE 2005

Simple categorisation of users Novice users

no syntactic knowledge, little semantic knowledge

may have little task knowledge may have anxieties about computer use

HFSD ISDE 2005

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

HFSD ISDE 2005

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