Many of the benefits of focus groups also apply to interviews. Interviews afford the opportunity to gather richly detailed information about how users go about their tasks, the conditions surrounding the task, and problems they had during the process. The benefit of an interview over a focus group is that more detail about individual experiences can be collected. They are also valuable for discussion of sensitive topics that people might not want to discuss in a group setting (e.g., health issues). Different questions can be marked as follow-ups depending on answers and an interview can also be paired with observation of the task. The main limiting factor in the quality of data is the interviewer and the script used during interviewing: a poorly worded or vague script can result in useless data. It is important to pre-test the interview questions to make sure that the participant understands the questions and that the participant interprets the questions in the way intended by the researcher. Be ready to adjust to any hearing needs. In-person is best, as physical and social cues can help with communication.
User observations can occur with a product or system of interest or consist of observing how users act in an environment where a product will eventually be used. In the second case, observational studies can contribute greatly to initial design specifications and often reduce the number of iterations required in usability testing. For observation studies, it is best to collect data in the location of use. For example, it may be possible to bring an older user to a test kitchen to understand their use of a display while cooking. But it may be more valuable to create a protocol to observe users in their own kitchens. For all observation studies, we recommend pilot testing the method of data collection, whether it is coding a recorded session or marking behaviors during observation. Further, provide a social warm-up time before beginning the observation.