ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved Users and User Characteristics

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved Contents Users - Designing for diversity Characteristics of users

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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)

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved Categorisation of Users We shall consider two main ways of categorising users: –occupational categories –level of expertise task expertise computer expertise

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved Three-Dimensional Framework Three Dimensional Framework for User Classification Knowledge of Computers Knowledge of Task Frequency of Use (low)(high)

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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).

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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).

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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. ?

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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.

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved Simple categorisation of users Novice users –no syntactic knowledge, little semantic knowledge –may have little task knowledge –may have anxieties about computer use 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

ID sept 03 John T Burns© Copyright De Montfort University 2003 All Rights Reserved 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