1. Design Principle Hierarchy

2. GUEPs  Generative User Engineering Principle  Defined by Thimbleby, Interact ’ 84, 661-666  Helps users deduce rules for a system  Bridges conceptual gulf between designer and user  Clarifies design requirements

3. Explaining An essential part of designing a user interface is explaining its operation. Examples:  A well-designed icon  A pop-up label box for a button  Meaningful titles on web pages  Dimmed options when not appropriate

4. KISS Make explanations simple and brief. By implication, fix designs that cause complicated explanations. Examples:  Remove dialog boxes with only one choice

5. Mental Model Ensure that the user constructs and can use an appropriate mental model of the system. Examples:  The desktop  Zoom as a hot air balloon

6. Improvement One can improve the computer program and change the documentation to match OR one can improve (or support) the user program and change the code to match. Examples:  Size the text entry box to fit the data

7. Consistency Employ a consistent and predictable design so that the system can be used successfully with the monitor turned off. Examples:  The default button can be activated with the Enter key.  Standard features appear in the same place with the same syntax and semantics across applications

8. Modelessness The user can do anything anywhere. Examples:

9. Output WYSIWYG: What you see is what you get. Examples:  Any direct manipulation widget  The print preview option

10. Display Inertia When the user goes back, everything is as it was before. Examples:  Windows Explorer or iOS Finder maintains the previous style of list view when reopened.  Scroll location is maintained on long web pages.

11. Bread Crumbs Leave a trace of where the user has been Examples:  Maintain the recently used documents list  Maintain the history file for the web browser

12. Summary  Explaining  KISS  Mental Model  Improvement  Consistency  Modelessness  Output  Display inertia  Breadcrumbs