Dialogue Styles

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Dialogue Styles
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The Primary Styles of Interaction

• Q A
• Menu selection
• Form fill-in
• Command language
• Natural language
• Direct manipulation

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Q A

• Simple interaction style
• Users respond to series of questions
• Input is usually Y/N or a particular single input
• Print whole document?
• No of pages to print?
• No of copies

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Advantages of Q A

• Easy to learn
• Good for novice or casual users
• Errors can be trapped
• User is led step by step through the task

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Disadvantages of Q A

• Task has to be clearly defined and quite narrow
• Have limited functionality
• Not sophisticated

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Menu Selection

• Employs metaphor of restaurant menu
• Users read list of items select appropriately
  according to task apply syntax to indicate
  selection confirm choice initiate action
  observe effect
• Designers may need to use careful task analysis
  to ensure all functions supported conveniently,
  and that terminology is appropriate and
  consistent in use

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Advantages and Disadvantages of Menus

• Advantages
• shortens learning curve
• reduces keystrokes
• structures decision-making
• permits use of dialogue-management tools
• allows easy support of error-handling
• Disadvantages
• imposes danger of deep-nested menu hierarchies
• may slow frequent users
• consumes screen real estate
• requires rapid display rate

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Form Fill-in

• Paper forms can be used as metaphor (or indeed,
  template)
• Users see a display of related fields move a
  cursor among the fields, and enter data as
  appropriate
• Designers need to ensure that users understand
  field labels, appropriate values and the
  data-entry method, and are capable of responding
  to error messages - some user training may be
  necessary

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Advantages and Disadvantages of Form Fill-in

• Advantages
• simplifies data entry
• requires modest training
• makes assistance convenient
• permits use of form-management tools
• Disadvantages
• consumes screen real estate

10
Command Language

• Appropriate metaphor may be military parade
  ground!
• Users learn syntax can express complex
  possibilities rapidly without reading distracting
  prompts
• Designers must allow for high error-rates
  diversity of possibilities and complexity of
  mapping from task to computer syntax is hard
  user training is necessary

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Advantages and Disadvantages of Command Language

• Advantages
• flexible
• appeals to power users
• supports user-initiative
• convenient for creating user-defined macros
• Disadvantages
• poor error handling
• requires substantial training and memorisation

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Natural Language

• Utilises conversational metaphor
• Users enter natural language sentences computer
  often seeks clarification before beginning task
• Designers need to understand task domain to
  narrow range of interpretations to manageable
  level design is extremely difficult.

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Advantages and Disadvantages of Natural Language

• Advantages
• relieves burden of learning syntax
• no training!
• Disadvantages
• requires clarification dialogue
• may require more keystrokes
• may not show context
• is unpredictable

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Direct Manipulation

• Metaphor is of a virtual world representing the
  real world
• Users point at visual representations of objects
  and actions, carry out tasks rapidly and see
  immediate results keyboard control replaced by
  cursor-motion control devices
• Designers need to choose appropriate icons and
  graphics to successfully immerse the user -
  minimal user training indicated

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Advantages and Disadvantages of Direct
Manipulation

• Advantages
• presents task concepts visually
• easy to learn
• easy to retain
• permits error avoidance
• encourages exploration
• permits high subjective satisfaction
• Disadvantages
• may be hard to code
• may require graphics displays and pointing devices

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Shneidermans Eight Golden Rules of Dialogue
Design

• 1. Strive for consistency
• 2. Enable frequent users to use shortcuts
• 3. Offer informative feedback
• 4. Design dialogues to yield closure
• 5. Offer simple error handling
• 6. Permit easy reversal of actions
• 7. Support internal locus of control
• 8. Reduce short-term memory load

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Menu-Selection Form Fill-in

• Additional Guidelines

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Menu selection design guidelines

• Semantic organisation
• sensible, understandable, memorable menus must
  have logical grouping of options based on users
  task
• single menu is simplest, but options are few
• (in GUIs radio buttons or check boxes can be
  used)
• binary (Yes/No) menus are a possibility
• extended menus (multiple pages are more normal)

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Extended menus

• Strategies for extended menus include
• multiple screens accessed hierarchically
• scrollable single windows
• pull-down menus lower levels invisible until
  accessed from a top menu bar
• pop-up menus context-sensitive availability of
  option lists

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Menu selection guidelines

• Use task semantics to group menu options
• Use broad and shallow options rather than
  narrow and deep
• Make items brief show position by numbers,
  graphics or titles
• Use meaningful sequences of items
• Use consistent grammar, layout, terminology
• Provide short-cuts (e.g., hot-key combinations)
• Allow jumps to previous menus

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Form fill-in design

• Meaningful titles - dictated by task, not
  computer, semantics
• Comprehensible instructions
• brief, jargon-free instructions preferred
• Logical grouping and sequencing of fields
• close as possible to paper form template
• Visually appealing layout
• uniform spacing is better than crowded areas
• Familiar field-label names and order of entry
• left-to-right, top-to-bottom but with task logic
  in mind

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Form fill-in Error handling and feedback

• Error correction for individual characters and
  entire fields
• user should not be forced to complete data
  entry before backtracking to make corrections
• Clear error-messages and on-line help for invalid
  entries
• Optional and compulsory fields clearly
  distinguished
• Clear completion signal
• avoid making completion automatic explicit
  confirmation of finish is preferable