Balancing Form and Function

1. Balancing Form and Function • Form and Function • High Usability • Aesthetically Pleasing • Error Messages • Non-anthropomorphic Design • Design Display Guidelines • Display Efficiency • Display Complexity • Multiple Windows • Image Browsing • Use of Color

2. Balancing Form and Function • Error Messages • Capture errors as a basis for design enhancements to avoid errors • Error messages should provide constructive guidance in a positive tone • Specificity • Be specific and precise • Indicate what the user needs to do • Choose user center phrasing • SYNTAX ERROR vs. Unmatched left parenthesis • ILLEGAL ENTRY vs. Type first letter: Send, Read, Drop • INVALID DATA vs. Days range from 1 to 31 • BAD DATE vs. Drop-off date must come after pickup date • Maintain consistent grammatical forms, terminology and abbreviations

3. Balancing Form and Function • Error Messages • Maintain consistent visual format and placement • Mixed case • Avoid error codes, or place at the end of the message • Location • On the display near the error • On the bottom of the display • Dialog box • Solution: allow the user to customize the placement • Developing effective messages • Pay more attention to message design • Quality control with programmers, users and usability specialists • Develop guidelines • Usability tests • Record frequency of error messages

4. Balancing Form and Function • Examples

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7. Balancing Form and Function • Non-anthropomorphic Design • Computers communicating like people • The user should feel they are in control • Such interfaces are distracting and create anxiety • The computer should be transparent • Is this guy annoying? • Computer messages • Poor: I will begin the lesson when you press RETURN • Better: You can begin the lesson by pressing RETURN • Better: To begin the lesson, press RETURN • Avoids overuse of pronouns http://www.youtube.com/watch?v=jQggTfZIstk&feature=related

8. Balancing Form and Function • Non-anthropomorphic Design • Interfaces should neither compliment or condemn users, but provide comprehensible feedback to assist users in achieving their goals • Human author to guide through training is sometimes acceptable to end users

9. Balancing Form and Function • Display Design Guidelines • Provide all necessary data in the proper sequence • Provide meaningful groupings with labels familiar to the users • Justifications (left/right) • Alignment of decimal points • Do not require the user to convert data • Order lists alphabetically if no other order applies • Left-justify columns of alphabetic data to permit rapid scanning • Of course there many more…

10. Balancing Form and Function • Empirical Results • Expert users may prefer dense displays • Performance times may be shorter with fewer but denser displays than with more numerous but sparse displays • This is especially true for tasks that require comparison of information across displays • Staggers (1993) • A study of nurses reading laboratory reports on three different screens • Three-screen version • Two-screen version • Densely packed one-screen version • Results: Search times dropped by half over five blocks for novice compared to experience users • Due to a strong learning effect • High cost of switching windows and reorienting

11. Balancing Form and Function • Display-complexity metrics (Tullis 1997) • Overall density – the number of filled character spaces as a percentage of total spaces available • Local density – the average number of filled character spaces in five degree visual angle around each character • At normal viewing distances from displays, this area translates into a circle approximately 15 characters wide and 7 characters high • Grouping – the number of groups of “connected” characters • Layout complexity – based on information theory, the distribution of horizontal and vertical distances of each label and data item from a standard point on the display • Studies indicate that effective display design contains a middle number of groups (6 to 15) that are neatly laid out, surrounded by blanks, and similarly structured • Grouping reduces scanning time

12. Balancing Form and Function • Display-complexity metrics – Bad Design

13. Balancing Form and Function • Display-complexity metrics – Good Design

14. Balancing Form and Function • Structure data based on relationship between objects • Minimize eye movements • Display-complexity metrics – Efficiency Initial Focus

15. Balancing Form and Function • User preferred web sites based on the following criteria (Ivory and Hearst – Webby Awards) • Columnar organization • Limit animated graphical ads • Average link text was kept to two to three words • San serif fonts were used • Varied colors were used to highlight text as well as headings Columns

16. Balancing Form and Function • Window Design • If window-housekeeping actions can be reduced, users can complete their tasks more rapidly, and with fewer mistakes • Coordinating multiple windows • Example: Insurance Claims Processing • Agent retrieves information for a patient • Primary window: patient address, TN, MRN • Second window: patient’s medical history • Third window: the record of previous claims • Synchronous scrolls across related windows • E.g., medical history window with the previous claims window • When finished, data in all windows is saved and all windows closed

17. Balancing Form and Function • Coordinating multiple windows • Coordination: objects changing on user actions • Synchronized scrolling: scroll bars from two different windows are synchronized • Hierarchical browsing: e.g., one window contains a table of contents, and a second window the chapter is displayed

18. Balancing Form and Function • Coordinating multiple windows • Opening/closing of dependent windows • Saving/opening of window state • “Save screen layout as…” 2nd window Primary Window 3rd window 4th window

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20. Balancing Form and Function • Image Browsing • Hierarchical view: users see an overview in one window and details in the second window • Zoom Factor: Magnification from the overview to the detail view (often the zoom factor is between 5 and 30) Overview

21. Balancing Form and Function • Image Browsing - Map View to Street View

22. Balancing Form and Function • Image Browsing • Fisheye views http://www.youtube.com/watch?v=EECi-OYXQqw

23. Balancing Form and Function • Image Browsing • The design should be governed by the user’s task • Open-ended exploration: browse to gain and understanding of the image • Diagnostic: scan for flaws • Navigation: seeking details (e.g., highway) • Monitoring: watch in overview mode, then zoom in on details

24. Balancing Form and Function • Personal Role Management • Different views for different roles • Example: • Student • Faculty

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26. Balancing Form and Function • Color – Form and Function • Soothe or strike the eye • Make a display more interesting • Evoke emotion • Provide discrimination of objects in a complex display • Facilitate the logical organization of information • Use to indicate abnormal conditions • Principles regarding the use of color • Use color conservatively: overuse can lead users to seek relationships that do not exit • Limit the number of colors: between 4 and 7 • Consider the power as a coding method: e.g., red = warning, green = stable state

27. Balancing Form and Function • Principles regarding the use of color • Match color coding to the task • Accounting: if accounts overdue are red • Design for monochrome first • Forces to layout the information in a logical pattern • Color deficiency • 8% of males have some type of color-blindness • Use double encoding • Use for formatting • Police cars responding to emergencies coded red • Be consistent in color coding

28. Balancing Form and Function • Principles regarding the use of color • Consider problems with color pairings • Red on Blue • Blue on Red • Yellow on Purple • Yellow on White lacks contrast • Eye muscles are strained attempt to create a sharp focus Very difficult to read Difficult to read Difficult to read

29. Balancing Form and Function • Principles regarding the use of color • Use color to indicate status changes • Applications to process control systems • User color for graphic data displays