Once the objectives of a usability test have been set, it is time to recruit the participants for the study. The golden rule of recruiting for this type of study is to recruit people who will actually be using your designs, such as your customers. The goal of the website is to be useable by real people who are likely to use your website, not demographics of people that have no interest at all. For example, if we study the demographics of visitors to the Numinix website we’d find that most of our visitors are over the age of 30 and are male. If we then create a group of participants that match this demographic, we’d be unlikely to collect any meaningful data unless these individuals were also small business owners or web developers.
Jared Spool (User Interface Engineering) interviewed Dana Chisnell, author of the Handbook of Usability Testing, on the misconception of targeting demographics for usability testing: Avoiding Demographics When Recruiting Participants: An Interview with Dana Chisnell.
Now that your usability test has objectives and participants, it is time to design the tasks that your participants will perform.