Picking Test Subjects
In theory, anyone who is able to understand your tasks and interact with your software prototype could be a test subject for your usability test. However, the biases and experiences of your test subjects will color your results. In practice, you are likely to get the most useful input from people who are actually members of your target audience. To determine whether or not someone would be a useful usability test subject, consider the following two questions.
- First, could the test subject be a member of your target audience?
- Subjects who are outside of your target audience may be able to provide you with insight as to the general usability of your program, but they are unlikely to notice small organizational problems which require an understanding of your subject matter-- like confusing labels, or badly ordered options.
- Second, how are the person's individual biases likely to shape her reaction to your software?
- For example, someone whose primary experience is with MacOS is unlikley to uncover problems with keyboard navigability, because MacOS tends to focus heavily on using pointing devices. Or, someone whose favorite mail client is mh and who does all his work from the command line is unlikely to notice the idiosyncracies of your implementation of drag and drop. The survey questions which you ask your test subjects in the usability test introduction should help you to contextualize his performance on your test.