The support of managers, colleagues and customers in the development and testing of a complex product or web site is vital. Planning the sequence of events and judging the time required can be hard to estimate, and this is often particularly true for usability engineering because of its relatively high reliance on subjective data. This element of uncertainty is a factor which can increase the risk that usability testing is kept to a minimum or dispensed with altogether, especially if usability testing is not part of a formalised department or process.
Much of the development work carried out by usability engineers is intended to address the time and resource-intensive nature of the usability testing process with a view to ensuring that at least some testing gets done. Certain testing techniques are now widely used as methods of gaining a good general overview of a product's usability as well as a quick way of identifying potential as well as actual problems. Many of these can be done by a small number of people in a single day or afternoon, but represent a significant investment in product quality.
Two of the most popular belong to a set of techniques called Usability Inspection methods, and are known as Thinking Aloud and Cognitive Walkthrough:
Thinking Aloud
Thinking Aloud is a deceptively simple technique whereby a test participant performs a sequence of tasks as part of their interaction with the product. Instead of relying on the standard measures of task completion, error and usability engineer's observations, the test participant is asked to vocalise their thoughts, intentions, feelings and opinions throughout the entire testing procedure, which can be recorded on video or simply written down by an observer.
Thinking Aloud improves with practice since the articulation of internal thoughts requires its own effort which may distract from the actual task at hand. Typically the test participant will be asked to try the technique by articulating the act of picking up a pencil, observing and describing the pencil, forming an intention to use the pencil, deciding whether to sharpen it or not, and beginning to write. Once they are comfortable with this they can begin to use your product or web site, articulating their observations and intentions as they do so.
Thinking Aloud is a very direct route to important information about the way users form goals and intentions and the kind of strategies they evolve to meet these goals. This technique can reveal mismatches between what users are looking for versus what they are actually seeing and show how real events happening with the product map onto user expectations (or not). The terminology users employ to express themselves can be incorporated into the product to enhance understanding. Periods of apparent silence or user inactivity can become rich sources of usability information, quickly and cheaply.
Cognitive Walkthrough
Cognitive Walkthrough can take place very early on in the design of a product, often before any physical material is available for viewing or testing. The process involves an expert evaluator (who may be an expert in the type of product under test, but also requires some awareness of usability issues) 'walking through' a set of tasks likely to be attempted by a user. The reviewer behaves as if the interface were actually built and they (in the role of a typical user) were working through the tasks. Each step the user would be expected to take is scrutinised to ensure that an appropriate sequence of events is both possible and obvious. Any points at which the interface blocks the user from completing the task are identified and the missing interface object specified.
Cognitive Walkthroughs can be performed using tools as simple as pen and paper, with the various interface elements and their effect on user goal achievement recorded and modified as necessary. This technique captures both the thought-based (cognitive) aspects of user interaction as well as the physical actions (button presses, mouse clicks etc) and quickly identifies unnecessary complexity and omissions.
Both Thinking Aloud and Cognitive Walkthrough are low-cost techniques requiring minimal investment in expertise and time, but yielding a comparatively rich usability data set. Their effectiveness means that both techniques have been considerably enhanced over time, with versions including, for example, ground rules to prevent testers losing focus or becoming defensive over interface elements they may have designed themselves. Even without formal usability testing resources, either of these inspection methods can provide a powerful data set for product improvement.
Joanna Bawa is a usability consultant and technical writer. She has worked with small agencies and large corporations for the past 15 years to analyse, review and improve upon the quality and usability of their information.
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