1. Principles and Methods
User Interface Design 1
Principles and Methods

2. User interface metaphors
dialogue metaphor
direct manipulation (event-driven, GUI) metaphor

3. User Interface Design Guidelines
Consistency – helps a user learn an application and apply what they know across different parts of that application.
Guidelines in corporate style guides help here (e.g. Microsoft UX).

4. User Interface Design Guidelines
2. Appropriate User Support- when the user does not know what action to take or has made an error.

5. User Interface Design Guidelines
3. Adequate Feedback Show the user what is happening e.g. cursor position, eggtimer, progress monitor, status bar, highlighting, boxing.

6. User Interface Design Guidelines
4. Minimal User Input
use of codes and abbreviations
selecting from a list rather than typing in a value
not having to enter information that can be derived automatically, using default values.
Key combinations can be used to speed things up for expert users.

7. Style Guides
Microsoft Windows Application user interface development guidelines
Windows UX- User Experience Interaction Guidelines

8. Visual Index http://msdn.microsoft.com/en-us/library/bb328626.aspx
This shows guidelines for the use of wpf components – when and how to use them, common mis-uses.

9. Approaches to design
Structured – uses task hierarchies e.g. STUDIO: task hierarchy diagrams, knowledge representation grammars, task allocation charts, state machines.
Ethnographic – detailed qualitative study of users and tasks
Scenario-based - draw out storyboards of scenarios , or describe them textually.
Aspects of all approaches can be combined.

10. 1. Structured UI Design: Stages
Requirements gathering
determine the types of user, frequency of use, task experience level, computing skills etc.
Determine task characteristics : complexity, breakdown, goal, context, task environment
Constraints, objectives, hardware, software, desired throughput, acceptable error rate
Interface design – allocate elements of task to user/system, determine communication requirements, design interface elements to support communication.
Interface evaluation – develop prototypes and test on users.

11. Task Hierarchy Breakdown*
Sequence
Repetition
(iteration) o o
Selection

12. Example Book Flight Enter Flight details Show Flights available
Take Payment
Confirm
Booking
Existing
customer O
New Customer O
Show flights and prices *
Select flight O
Abandon O

14. State Machines
- similar to UML – more on this later

15. Ethnographic Approaches
Qualitative assessment of task situation where the designer works very closely with the user in their work context.
Observing
Listening
Asking questions
Interviews
E.g. Participative design

16. Scenario-based Approaches
Step-by step descriptions of user actions showing how users can achieve a goal
Can use textual narrative or storyboards.

17. Usability Criteria Learnability - time and effort needed
Throughput of the expert user
Flexibility – ability to handle changes to tasks and the environment in which they operate.
Attitude – how positive does the user feel as a result of his/her experience with the package?
ISO definition of Usability : degree to which users can achieve specific goals in a particular environment ; effectively, efficiently, comfortably and in an acceptable manner

18. Standards and Legal Requirements
Accessibility standards
Web accessibility initiative
ISO usability standards

19. Schneidermans Golden Rules
Strive for consistency. Consistent sequences of actions should be required in similar situations; identical terminology should be used in prompts, menus, and help screens; and consistent commands should be employed throughout.
Enable frequent users to use shortcuts.
Offer informative feedback.

20. Schneidermans Golden Rules
Design dialog to yield closure. Sequences of actions should be organized into groups with a beginning, middle, and end. The informative feedback at the completion of a group of actions gives the operators the satisfaction of accomplishment, a sense of relief, the signal to drop contingency plans and options from their minds, and an indication that the way is clear to prepare for the next group of actions.
Offer simple error handling. As much as possible, design the system so the user cannot make a serious error. If an error is made, the system should be able to detect the error and offer simple, comprehensible mechanisms for handling the error.
Permit easy reversal of actions.
Support internal locus of control. Design the system to make users the initiators of actions rather than the responders.
Minimise memorisation
Adapted from from