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154 CHAPTER 7 Case studies

In a truly reflective style, we look closely at an example of HCI case study re-
search to understand what is involved. Close examination of this one case will il-
lustrate when case studies are appropriate, how they might be designed, how cases
are chosen, how data might be collected, and how the data can be interpreted.
Examination of this specific case provides us with a clearer understanding of the ap-
plication of case study research.

7.2 OBSERVING SARA: A CASE STUDY OF A CASE STUDY
Concerns over the limits of narrowly constructed usability studies led Shinohara and
Tenenberg to conduct an in-depth examination of a blind person's use of assistive
technologies (Shinohara and Tenenberg, 2007). By examining the use of a range
of technologies in the user's home, they were able to address several questions that
would have been difficult to consider in a lab-based usability study. Specifically, they
looked at types of task that were common across multiple technologies, including
both digital and physical objects, in order to identify general strategies and under-
stand the trade-offs involved in hardware and software design.
Shinohara and Tenenberg used a series of semistructured interviews (see
Chapter 8) to collect the observations that form the basis of the case study. In a series
of 6, 2-hour sessions in her home, Sara (not her real name) demonstrated how she
used technologies such as tactile wristwatches and screen readers; discussed early
memories of using various objects and her reactions to them; and imagined improved
designs for various objects or tasks. Notes, audio recordings, interviewer reactions,
and photographs from these sessions provided the raw data for subsequent analysis.
Insights and theories based on early observations were shared with the subject for
validation and clarification.
Analysis and presentation of the case study data took multiple forms. Twelve
tasks were recorded in terms of their intentions/goals, limitations, workarounds, and
desires for future improvements (see excerpt in Table 7.1). This table can be used to
compare and group seemingly unrelated tasks in search of common themes. Detailed
descriptions—complete with representative quotations—of Sara's use of a tactile
watch and screen-reader software complement this table with illustrative details. For
example, discussion of the tactile watch led to a deeper understanding of the impor-
tance that Sara placed on aesthetics and her desire to be unobtrusive, as she preferred
the comfortable, silent tactile watch to a talking watch, which was both noisier and
larger. Examination of Sara's use of a screen reader led to the observation that she
would examine all possible options, possibly even restarting from scratch, in order to
achieve a goal (Shinohara and Tenenberg, 2007).
Building upon the insights from the individual tasks, Shinohara and Tenenberg
identified several general insights that could guide the design of improved tools.
Examples included the importance of designs that would not make users feel self-
conscious when interacting with sighted friends or colleagues; the importance
of control, efficiency, and portability; the need for tools that ease the process of