Usability Requirements and Testing
INFORMATION TASKS: toward a user-centered approach to information systems
Academic Press, New York, 1996
Jeffrey Rubin
HANDBOOK OF USABILITY TESTING: how to plan, design,
and conduct effective tests
John Wiley & Sons, New York, Toronto, Chichester,
Brisbane, and Singapore, 1994
The Phenomenology of Information Needs
The task that people use information for, is the search for solutions to their problems, however they define them, and however they go about it. Information systems, which consist of participants, their problems, their search strategies, and the technologies they use, should be architected to fulfill the task that gives them their purpose, i.e., assisting people. As Bryce Allen explains it, it seems so simple and obvious - but as he is the first to concede, this is an ideal toward which we should work rather than a reality from which we currently benefit.Information Tasks is probably the most cogently thought-out and clearly-written book on "peopleware" available to date. Starting from first principles, Allen has crafted first a literature review, and then a design philosophy which is both elegant and persuasive. What research on usability indicates so far, is that we cannot, by and large, second-guess what users need to make their information systems effective. We must do adequate field research, or we simply won't know the basis for proper design.
Once we admit our ignorance, and commit ourselves to that research, Allen walks us through an enquiry paradigm whose cumulative stages do lay the foundations for a design synthesis. His two closing chapters consider some of the wider social implications of this approach. Furthermore, in all likelihood, the shift to this perspective is as much attitudinal as it is cognitive. In other words, if you don't feel more affinity for people rather than technology, you may not find the case for usability requirements convincing, which means you are part of the problem rather than part of the solution.
Fortunately, more and more of those in the marketplace are shopping with usability in mind, and for anyone so inclined, Information Tasks shows the wave of the future. But the designers who have "bought into" the user-centered approach face another dilemma. Donald Norman has shown that there is a social psychology to how we interact with artifacts. So, is there a common cultural basis for interface design or not? The answer is "yes and no".
Groups which share a culture do possess a "metaphorical inventory" upon which affordances can be based. Beyond these foundational elements however, sophisticated functionality and usability must be learned. This is where research must inform the differential design. In place of metaphors, we must design around idioms, and instead of affordances, the result will be competencies. This is why Allen (and designer Alan Cooper) emphasize the motivation of the user as an important part of the effective use of an information system -- if effective interaction requires some learning, the interface must be designed to motivate engagement as well as to facilitate navigation. As Allen never tires of reminding us, information tasks are a form of human behaviour, not just mechanical search and retrieval.
This book is available through
Amazon.com Bookstore.
This Is Indeed a Test!
Jeffrey Rubin shows us how to test products to ensure that the good intentions of usability are actually turned into practice. Testing should begin during the design process, in the form of prototypes which try out selective features on small samples of customers and/or confederates. Faults and failures can then be identified and eliminated.But even with such good methods, inadequacies of both functionality and usability are bound to crop up in alpha and beta testing. Staging the testing, and dealing with the results, are the themes of Rubin's book. Because he aims to be both thorough and practical, Rubin treads a fine line between formality of methods and the urgency to get results. He preserves credibility be giving a number of parallel scenarios, from the "quick and dirty" for rush jobs, to the planned and elaborate when the time and budget are available.
Just as Allen's design paradigm consists of a sequence of stages, so Rubin's testing paradigm also has a logical order and progression to it. Even in the face of short time and little money, systematic notes and prioritized responses are essential so that learned lessons can be factored into better designs. And not entirely by co-incidence, Rubin's approach is also based on user-centered design.
Besides the usability testing methods themselves, the main argument of Rubin's book, is that testing itself requires considerable learned competencies. Staging a set of tests, and then extracting the lessons from the participants' responses, is not a job for amateurs, nor can it be an after-thought to development. Effective testing requires training, and it can only occur when testers are respected contributors on the development team, and their input is a determining part of the eventual product. Just as users' needs are the premise for the product, the users' presence on the development team is represented by the testers.
Users needs should not only be the basis for requirements specifications, but as well, their acceptability responses should be the basis for usability testing. In other words:
- has the design process
been informed by what users actually need?
AND
- do users agree that the products
so produced have adequately incorporated
their requirements into the proper balance of functionality and usability?
Rubin's techniques allow us to test for the answer, and to the extent that the answer is "NO", Allen will show us back to the drawing board!
[A development process which turns usability requirements into usable products, IS currently practiced by Deborah Hix and Rex Hartson.]
This book is available through
Amazon.com Bookstore.
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