HCI - User Support

Approaches to user support

• Command assistance
• user requests help on particular command
• Good for quick reference
• Assumes user know what to look for
• Command prompts
• provides information about correct usage when an error occurs
• Good for simple syntactic errors
• Also assumes knowledge of the command
• Issues
• different types of support at different times
• implementation and presentation both important
• Require careful design
• Types of user support
• quick reference, task specific help, full explanation, tutorial
• Provided by help and documentation
• help - problem-orientated and specific
• documentation - system orientated and general
• same design principles apply to both
• Approaches to user support
• context sensitive help
• help request interpreted according to context which it occurs
• Online tutorials
• user works through basics of application in a test environment
• can be useful but are often in flexible
• Online documentation
• paper documentation is made available on computer
• continually available in common medium
• can be difficult to browse
• hypertext used to support browsing
• Requirements
• Availability
• continuous access concurrent to main application
• Accuracy and completeness
• help matches and covers  actual system behaviour
• Consistency
• between different parts of the help system and paper documentation
• Robustness
• correct error handling and
• predictable behaviour
• Flexibility
• allows user to interact in a way appropriate to experience and task
• Unobtrusiveness
• does not prevent the user continuing with work
• wizards
• task specific tool leaders the user throguh task, step by step, using user's answers to specific questions
• example: resume
• useful for safe completion of complex or infrequent tasks
• constrained task execution so limited flexibility
• must allow user to go back
• assistants
• monitor user behaviour and offer contextual advice
• can be irritating
• must be under user control
• Adaptive Help System
• use knowledge of the context, individual user, task, domain and instruction to provide help adapted to user's needs
• Problems
• knowledge requirements considerable
• who has control of the interaction
• what should be adapted?
• what is the scope of the adaptation
• Knowledge representation 
• Domain and task modelling
• covers common errors and tasks
• current tasks
• Usually involves analysis of command sequences
• Problems representing tasks
• interleaved tasks
• user intention
• User modelling
• All help systems have a model of the user
• single, generic user (non-intelligent)
• user-configured model (adaptable)
• system-configure model (adaptive)
• Advisory strategy
• involves choosing the correct style of advice for a given situation
• few intelligent help systems model advisory strategy
• Approaches to user modelling
• Quantification
• user moves between levels of expertise
• based on quantitative measure of what he knows
• stereotypes
• user is classified into a particular category
• Overlay
• idealized model of expert use is constructed
• actual use compared to ideal
• model may contain the commonality or difference
• Special case: user behaviour compared to known error catelogue
• Techniques for knowledge representation
• rule based
• knowledge presented as rules and facts
• interpreted using inference machanism
• can be used in relatively large domains
• frame based
• knowledgestored in structures with slots to be filled
• useful for a small domain
• network based
• knowledge represented as relationships between facts
• can be used to link frames
• example based
• knowledge represented implicitly within decision structure
• trained to classify rather than programmed with rules
• requires little knowledge acquisition
• Problems with knowledge representation and modelling
• knowledge acquisition
• resources
• interpretation of user behaviour
• Presentation issues
• How is help requested?
• How is help displayed
• Effective presentation requires
• clear, familiar, consistent language
• instructional rather than descriptive language
• avoidance of block of text
• clear indication of summary and example information
• Issues in adaptive help
• initiative
• does the user retain control or can the system direct the interaction?
• can the system interrupt the user to offer help?
• Effect
• what is going to be adapted and what information is needed to do this
• only model what is needed
• scope
• is modelling at application or system level
• latter more complex
• expertise varies between applications