The tangible result of your work should be (1) a written list of all the messages identified by the members of your group, along with the reasons for their classification based on Shneiderman, and (2) a written list of your two distinguished nominees, along with specific reasons that they stand out among their peers.

Summary of Discussion

The most commonly cited heuristics were

• specificity,
• constructive guidance,
• positive tone,
• user-centered focus, and
• appropriate physical format.

How do you as an audience differ from the typical user audience that Shneiderman is concerned with? Experience, confidence, background.

How do these differences account for the kinds of answers you give? Relatively little, it seems! As an audience, you seemed to want the same sort of support that Shneiderman proposes. Maybe there is something to what he is saying?

The best messages were succinct, clear, and constructive. Some even offered to make the error go away.

The best message award went to the class of messages that tell you what went wrong and how to fix it--concisely. These include:

• "The printer is out of paper. Please load Tray 1 and hit Return."
• "No floppy in drive A. Please insert disk and hit Return."
• "Would you like to save before closing?"
• "The directory foo does not exist. Would you like to create foo now?"

Honorable mention for the best error messages include compiler messages that take you to the offending expression on a particular line number.

The worst were succinct and cryptic and often revealed some implementation details that you didn't care about.

The worst message award went to the class of messages that tell you a failure has occured, by number, and leave you with no recourse. These include:

• MacOS's "Error -1192" with the image of a detonated bomb.
• Windows's messages that do the same, with hex dump data.

Honorable mention for the worst error messages in...

• the operating systems category:

  • "Keyboard not found. Press F1 to continue."

  • The Blue Screen of Death.

  • One of my favorites from a past class was a system that generated sound tones on BIOS errors, with the pitch and duration of the tone distinguishing error modes.

  Just for fun, here are some error dialogs from Microsoft Windows. Are they real or fake? You be the judge. :-)

  [ Sorry -- this images fell victim to a Windows 2000-enabled virus when I logged into a PC in the lab. Grrr. I'll restore it when I find it again... ]

• the compiler category: Waiting for a good nominee! (A possibility from the department's past: gcc's error messages on template errors, especially nested ones...)

• the word processor category: Waiting for a good nominee!

  Just for fun, though, here is a hidden preferences dialog from Microsoft Windows. Is it real or fake? You be the judge. :-)

  [ Sorry -- this images fell victim to a Windows 2000-enabled virus when I logged into a PC in the lab. Grrr. I'll restore it when I find it again... ]

These bad error messages are the remnants of a leftover world, the results of attitudes that formed before personal computers filled every home, back when only real men used computers. Old habits die hard--if at all. We need to work hard to overcome the ruts of our industry.

Exercise 35: Guidelines for the Effective Use of Color

Work in the same teams as you did for Exercise 34.

Once again, I think that Shneiderman provides some nice rules of thumb that may not help me enough when I try to design an interface. Section 11.5 lists fourteen bullets with advise such as "use color conservatively". Okay... So what counts as conservative? Four colors? Three colors? Black on white? When is using more colors appropriate? Well, "when they identify meaningful relationships". Okay... Which relationships are meaningful? What if my system contains so many meaningful relationships that I have to break the number-of-colors rule. As you can tell, I'm confused again.

• Draw up a list of specific rules for the use of color in designing a web page. You may use Shneiderman's bullets as a starting point, but write rules that provide much more guidance. For example, you might say something like, "Use at most three colors on a web page."

• For each rule, list evidence that justifies the rule. Use Section 11.5 as a source for color-specific evidence, but feel free to use general presentation evidence from other sections of the chapter, too. For example, you might say, "Use of too many colors distracts the user from the content of the page..."

• For each rule, give at least one exception. Identify the specific situation that alerts the designer to the exception, and provide evidence that justifies bending the more general rule. For example, you might say, "If you are designing a page with several well-defined and conceptually distinct alternatives, which lie on a continuum that your user understands, use one color for each alternative. Choose colors that reflect the position of each alternative on the continuum. Using more than three colors works in this case because..."

Your group should be able to produce four or five rules of this sort in the time alloted. You may want to draw on your own experiences as software users and web surfers. Try to recall good and bad examples of web page design, and then try to distill what made them good or bad. Use Shneiderman's list to focus your search.

The tangible result of your work will be a single written list of rule-evidence-exceptions triples. Be prepared for us to discuss and critique your work!