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When
can Usability Testing do more harm than good?
When
it is conducted using inappropriate methodology for the stated objectives. What
is “usability testing?” There
are many different kinds of usability tests, and this variety can be
confusing to developers who are unfamiliar with usability research.
To begin to understand the differences between testing methods it
is important to consider the goals of the test. Do you want to compare the usability of your current product against older versions, your competitors’ products, or established usability standards? These are “criterion” tests (sometimes referred to as “summative” tests) and they can be extremely valuable in helping you make decisions about the relative usability of your product. Criterion tests can help you determine which aspects of your product need to be improved, or determine how your product stacks up against the competition. If it turns out that your product is more usable than the competition, you can even use the results in your promotional efforts! Do you want to find and fix usability problems? Then diagnostic usability testing is the method of choice (sometimes referred to as “formative” testing). Diagnostic tests are the most common type of usability test and are essential to any comprehensive usability effort. Diagnostic testing should be applied early and often throughout the product development process, and we know how to design usability tests for every circumstance. Why is it important to know which type of usability test to use? Both types of tests involve observing users (or potential users) in laboratory settings. Both types of tests rely on a thorough and accurate understanding of the users of your product and the tasks they will perform. However, a number of important differences between criteria and diagnostic tests must be considered in order to perform them correctly. If you want to achieve the goals of your test, you need to understand the differences! Should there be multiple, "iterative" usability tests, or just one? Who should the usability test participants be, and how many do you need? What tasks should test participants perform, and how should the tasks be presented to them? Should the participants "think aloud" or behave "naturally?" When should participants be "assisted," and what kinds of assistance should be provided? Which usability metrics are appropriate (i.e., which behaviors should be measured) and how should the results be interpreted? Are there other techniques, such as ethnographic research, focus groups, or task analyses that should be used in addition to usability testing? These are just a few of the questions that need to be answered before conducting a usability test--and answering them correctly requires knowledge and experience! TWS can provide the knowledge and experience you need in order to achieve your usability goals effectively, efficiently and with total confidence in the results. Email: drw@twsinc.com
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