Sit-By Sessions versus Observing from Elsewhere

When the practice of usability testing started, most sessions were conducted in a highly clinical style, with the moderator seated in a control room to observe and collect data. Over the years, a less formal "sit-by" style of conducting sessions has developed for circumstances under which one would want to be near participants during usability testing, including most of the types of tests we describe in this book. For example, being with the participant in the testing room is advantageous for exploratory situations in which one wants to be able to gather the first impressions of participants about the design or functionality of a product. Doing so allows the moderator to be able to ask follow-up questions easily in a more cooperative session.
Additionally, if there is very quick interaction that must be observ ed closely or if you are conducting paper prototyping sessions, the moderator must be with the participant to mimic the computer actions.

However, if there is a chance in an assessment or validation test that the moderator's presence may bias the data, or if the emphasis is on gathering quantitative rather than qualitative data, set the test up to let the participant work by him- or herself while you manage the sessions from another room. For a deeper discussion of the physical arrangements for testing and observation rooms, see Chapter 6.