1. Copyright 1999 all rights reserved Early Design n How to Start –Intelligent Borrowing Plagiarizing or Good Design PracticePlagiarizing or Good Design Practice –Working within Existing Frameworks Style GuidesStyle Guides Software ToolsSoftware Tools

2. Copyright 1999 all rights reserved Use of Existing Applications n Build add-ons –look at systems users already know n Copy interaction techniques –copy the style of menu selection, organization of screen elements, etc. (where appropriate) n Understand why design was done in the way it was done with the existing interface

3. Copyright 1999 all rights reserved Reasons for Design Decisions n Human motor performance arguments –items that are co-selected should be close –small items are hard to select –selection while holding the mouse button down is a harder motor task

4. Copyright 1999 all rights reserved Reasons for Design Decisions n Human memory arguments –keyboard entry requires someone to remember the name of the item –screen selection only requires someone to recognize the item –long command sequences hard to learn and to hold in the user’s head

5. Copyright 1999 all rights reserved Reasons for Design Decisions n Problem-solving arguments –problems can be hard to solve if represented poorly –if the user has to map their problem representation into a different one on the screen, the problem will be harder to do

6. Copyright 1999 all rights reserved Reasons for Design Decisions n Human visual performance arguments –important items stand out by varying properties of items, e.g., color, shape –user search guided by organization of screen elements, e.g., user’s eye navigates from left to right and top to bottom

7. Copyright 1999 all rights reserved Reasons for Design Decisions n Design convention arguments –user is already familiar with process order or arrangement from other interfaces –most of user interface design requires designers to work within the tight constraints of existing designs

8. Copyright 1999 all rights reserved Reasons for Design Decisions n Diversity Arguments –Application may be used in different countries large American trashcan on Macintosh computer looks silly in Europelarge American trashcan on Macintosh computer looks silly in Europe difficult to map single menu command to one in another language - requires re-organizing the menusdifficult to map single menu command to one in another language - requires re-organizing the menus –Application may be used by casual and dedicated users menu selection and accelerator keys both usedmenu selection and accelerator keys both used

9. Copyright 1999 all rights reserved When you must invent n What if the system’s never been built before? (e.g., one-of-a-kind) –Look harder for existing ideas e.g., coffee machine design copied to bank machinee.g., coffee machine design copied to bank machine –Try to uncover a conceptual model the user already has –Use an iterative process Build a little, test a lotBuild a little, test a lot