Disadvantages

- The test moderator's behavior can affect the behavior of the participant If you are not mindful of your speech, mannerisms, and so on you will inadvertently and subtly react to what the participant is doing. Even
if you do not make any outward remarks, the participant may pick up a sigh or a shift in your posture in response to what he or she is doing.
That in turn can cause the participant to veer off from the direction in which he or she was going or look to another page. It is especially crucial to avoid making notes when it appears the participant has finished
a task. This can cue the participant that he or she has finished a task successfully even if the participant is not sure. Likewise, your writing or typing may suggest to the participant that he has done something' incorrectly. Even if this is true, you do not want to telegraph that,