Categories: Software Part 1: Making Software Easier Through Usability Testing Part 3: Talkback: Tell us about usability gaffes you've found Related Stories: 1999 Software Sneak Preview Next: Talkback: Tell us about usability gaffes you've found

Continued from Programs with confusing interface actions

Dialog boxes must be well designed to be usable. Here, well designed means that the choices being offered are clear and that the user isn't confused about which choice to make. In fact, it's especially important that the user isn't afraid to make a choice. With either reaction, the user could experience a temporary paralysis, not knowing which button to click. Below are two dialog boxes which we'll examine from a usability perspective.

The alert shown in Figure 4 occurs in Microsoft Word 97 if the filename you specify in the Save dialog already exists in the current folder. The dialog asks whether you want to replace the existing document of the same name; your choices are Yes, No, and Cancel. Right off the bat there's a problem, because an inexperienced user won't necessarily know what replacing a document will actually do. The dialog would be more usable if it explained that replacing a document means the original will no longer exist (except in the case of automatic backups, but that's a different issue).

Figure 4: Microsoft Word 97 gives you a choice in its Save As dialog.

The major usability concern here, though, has to do with what happens in the case of No and Cancel. It's not apparent from the dialog, nor from simple logic, how the two choices differ. A novice user faced with this dialog could easily mistake the two, and click on No rather than Cancel. Again, this is only a problem for people who don't know the program, but a short explanation would help immensely.

Figure 5 shows the result of a relatively unusual event using Internet Explorer 4. If you go to a site where your actions post data to a form and then click on the Refresh icon to update that page, you'll be asked the question Repost form data?, to which you can answer Yes or No. The problem, of course, is that most users simply won't know what the question means. Users who have designed a form-based Web site will probably understand the concept, but there's no reason anyone else would. The dialog doesn't suggest what will happen if you select Yes or No. It's potentially paralyzing, even for a fairly experienced Web user.

Figure 5: Internet Explorer 4 presents this dialog when you refresh a form.

Next: Talkback: Tell us about usability gaffes you've found

Published as Tutor in the 10/20/98 issue of PC Magazine.