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196 CHAPTER 8 Interviews and focus groups

• Are you able to complete the comparisons that you want to do? If not, where do
you have trouble?
• Are any parts of the interface particularly useful or helpful?
• How does this interface compare to your current tool?
• What (if anything) would you like to change about this tool?
Additional questions for understanding user reactions to interface designs might
be based on existing usability questionnaires, such as the Questionnaire for User
Interface Satisfaction (QUIS) (Chin et al., 1988); the System Usability Scale (Brooke,
1996); the User Metric for User Experience (UMUX) (Finstad, 2010); UMUX-Lite
(James et al., 2013), or one of the others listed in Chapter 5.
The strengths and weaknesses of interviewing make it a strong complement to
several other techniques. For understanding a problem during requirements gath-
ering, a broad-based survey might be combined with a small number of in-depth
interviews. Complementary questions in the two formats would allow researchers
to combine a deep understanding of user needs and challenges (from the interviews)
with an appreciation of how well those concerns generalize to a larger set of poten-
tial users.
For evaluation of an existing interface, you might combine usability tests or
empirical studies aimed at understanding specific details of interface usability
with interviews that ask about general reactions. These interviews can help you
understand user perceptions, likes, and dislikes. This combination of results
from different approaches can be informative and perplexing: don't be surprised
if the usability or empirical studies are completely at odds with your interviews.
This seemingly inconsistent state of affairs may arise if you're comparing two
alternative designs: interviewees may prefer design A over design B, even
though your studies indicated that design B was somehow superior (perhaps
faster or less error prone) to A. These results present an opportunity for you to
dig deeper in search of insights that might help you reconcile the contradiction.
If you can find out why they preferred A, despite B's superior performance, you
might use that information to develop a design C that combines the best ele-
ments of A and B.

8.4 WHO TO INTERVIEW
Who should you interview? When you are running usability studies, empirical
tests, or observations, the question of participant selection starts from an obvious
point: current or potential users of your proposed system or alternatives. If your
interviews are aimed at trying to understand the pros and cons of specific features
of a proposed interface, users might be appropriate interviewees. In either case,
you might find that there are different categories of users who have differing
views. Including representatives of each type of user will help ensure that you
are not missing important perspectives. For investigations of broader concerns,