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September 6, 1999

New Mantra: Usability

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Illustration by Dennis Harms

Related links:

sidebar: Design Lucid Software With The User In Mind

sidebar: Put Flawed Software To The Test

PDF file: Point-Of-Sale Interface Mock-Up
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From the feedback, the paper designs are refined and turned into software using a prototyping tool. Screen painters or Microsoft Visual Basic are used to do a mock-up of the graphical front end; no back-end processing is programmed at this stage.

Once the front end can be shown to users, more formal usability testing begins. From these tests comes feedback that developers use to refine the interface. From here on, software development as such happens apace. How much more usability testing to do depends significantly on time and resources. In theory, the more testing you do, the better the product. Nonetheless, after a certain point, diminishing returns set in and very little that's new is brought to light.

The testing schedule is fairly thorough. By contrast, the requirements study and the design cycle are the minimum you should contemplate. Companies that don't believe they have the means and resources for testing labs and continuous usability testing should not be dissuaded by cost, says Marshall McClintock, Microsoft usability group manager. The cost is moderate, he says. More important: If your site is turning customers off, it's much more expensive not to do the testing.

Most professionals concur. An inexpensive lab can be fashioned with a video recorder, a tape recorder, and software that captures all keystrokes and user activity. Two packages that do this last activity well are Astra QuickTest from Mercury Interactive Corp. and Rational TestStudio from Rational Software Corp.

An important consideration is what to do with the results of the testing. Bill MacGregor, manager of performance-centered design at SMS Corp., a health-care software company, has developers watch the tests as they're being administered. Developers are required to mark their observations on sticky notes. After the tests, the notes are placed on a wall and grouped around common themes with the help of affinity diagrams. Affinity diagrams are a technique for grouping common issues from a nonstructured discussion, such as a brainstorming session. From these groupings, changes in the design are agreed upon. The tapes of the test serve to clarify a point or resolve differing interpretations of a user's difficulty.

Different Strokes
Ken Dye, who heads the usability testing program for Microsoft Office, says it's important to use feedback judiciously. This is especially true at Microsoft, given how often the company tests products for usability. "We fix show stoppers right away," he says. "After that, all observations on possible improvement are prioritized on the basis of how serious the problem is and how often the user is likely to encounter it."

But Cooper of Cooper Interaction Design says this view of feedback is exactly what's wrong with excess reliance on usability testing. "You look at a product like Microsoft Office and you see this very complicated interface that is not at all intuitive," he says. "And you realize that Microsoft has relied on its usability testing solely to confirm its decisions. Rather than redesign the interface to get it right, they use testing to continue refining a bad design."

Either way, it's clear that the need for interaction design and usability testing is here to stay. Keith Butler, who leads usability engineering at Boeing Co., is working with the National Institute of Science and Technology to require software vendors to provide usability-testing results to customers, effectively forcing vendors to conduct such tests. "Usability problems are an uncontrolled source of overhead," he says. Vendors should do the testing and provide evidence of the results. "Otherwise," Butler says, "we customers end up doing the testing for the vendor after we buy the package."

With that kind of pressure ahead, and the capriciousness of discretionary buyers at your Web site today, companies can no longer afford to neglect usability testing.

Andrew Binstock is a senior analyst at Pacific Data Works LLC in San Carlos, Calif. He can be reached at alb@pacificdataworks.com.

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Illustration by Dennis Harms

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