Prior to the development of the physical design of a product, the designers should be aware as to the tasks that the eventual users are going to be performing with the product. This knowledge can be gained using a task analysis, that provides information on how the current systems the users use integrates with task performance and how the task can be made easier. Rauch, Kahler and Flanagan (1996) list 8 questions that can be used to guide the task analysis.
It is essential that the task the usability test participants are performing be representative of the tasks of the finished product. During the planning of the usability test, the experimenters, in association with the designers, can define the tasks that encompass the usability of the product, and specify the test features that are undergoing iterative design. This is one of the more important steps in the test and can be one of the more difficult ones to overcome.
It is also important to define which characteristics of the product are under test. It is not recommended to only focus on the overall usability of the product, but also on some of the key elements. If a problem is found, it should be addressed fully and similar problems should be sought, which may not have been found by the participants. Effective planning and trial before the test will ensure that the test goes smoothly without any mishaps, will not waste any of the participant's time, and will increase the overall appeal of the test process. Task strategies can be formulated to probe existing usablity problems and can mould future task behavious with the eventual product. Tasks can be divided into groups that evaluate specific product features or assess particular aspects of usablity.
It is not recommended that the participants be immersed into testing the product with the specified tasks as soon as the test begins. It is important that the test users become familiar with the product and gain practice with it. If the tasks of test are complex and involve extensive use then the test should start with easier, less complex tasks for the test user to gain expertise and confidence. This is important because the test user should feel that it is not them but the product that is under the test. This belief will encourage them to be more participatory in the test, resulting in more usable information. Test times range depending on the complexity of the product and the tasks, thus it is essential that the participant feel that they are contributing to the product's development, especially in longer tests. In some cases, participant comments and concerns can not only provide insight into existing task procedures, but also establish a need to other tasks, and in most instances the participant will also provide a possible solution.