Dialogue Styles

1. Dialogue Styles

2. The Primary Styles of Interaction • Q & A • Menu selection • Form fill-in • Command language • Natural language • Direct manipulation

3. 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

4. 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

5. Disadvantages of Q & A • Task has to be clearly defined and quite narrow • Have limited functionality • Not sophisticated

6. Menu Selection • Employs metaphorof restaurant menu • Usersread 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

7. 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

8. Form Fill-in • Paper forms can be used as metaphor (or indeed, template) • Userssee 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

9. 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! • Userslearn syntax; can express complex possibilities rapidly without reading distracting prompts • Designersmust allow for high error-rates; diversity of possibilities and complexity of mapping from task to computer syntax is hard; user training is necessary

11. 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

12. 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.

13. 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

14. Direct Manipulation • Metaphor is of a virtual world representing the “real world” • Userspoint at visual representations of objects and actions, carry out tasks rapidly and see immediate results; keyboard control replaced by cursor-motion control devices • Designersneed to choose appropriate icons and graphics to successfully “immerse” the user - minimal user training indicated

15. 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

16. Shneiderman’s 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

17. Menu-Selection & Form Fill-in Additional Guidelines

18. Menu selection design guidelines • Semantic organisation • sensible, understandable, memorable menus must have logical grouping of options based on user’s 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)

19. 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

20. 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

21. 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

22. 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