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 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

7. Advantages and Disadvantages of Menus
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)
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

9. Advantages and Disadvantages of Form Fill-in
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

11. Advantages and Disadvantages of Command Language
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
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”
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

15. Advantages and Disadvantages of Direct Manipulation
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