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160 CHAPTER 7 Case studies

• description: documenting a system, a context of technology use, or the process
that led to a proposed design.

HCI case studies address these and one additional goal:
• demonstration: showing how a new tool was successfully used.

7.4.1 EXPLORATION
New research projects—whether in a lab or in a product development environment—
often begin with an incomplete or preliminary understanding of a problem and its
context. Case studies can provide invaluable feedback when a project team is in
the early stages of understanding both the problem and the merits of possible solu-
tions. Such studies would have members of the project team examining the goals
and constraints facing likely users. Using processes similar to those used in ethno-
graphic work (see Chapter 9), researchers might observe how potential users cur-
rently accomplish tasks, use available tools, and respond to problematic situations.
The insights that result from this inquiry can inform both system design and further
investigation.

7.4.2 EXPLANATION
Technologies in general, and computer systems in particular, are often used in ways
that were not considered in the initial design, often with impacts that are completely
unexpected. Case studies of tools in use can provide understanding of these uses and
outcomes. An examination of the use of a tool for browsing photo collections on mo-
bile devices provides an example of an explanatory study: in-depth interviews with
nine users provided substantial insight into how the tool was used and how specific
designs might engage users (Naaman et al., 2008).
The Extreme Cases sidebar describes a case study of the use of GPS location
devices for tracking parolees. In addition to explaining how these systems affect—
often in surprising ways—the behavior of the individuals required to wear them, this
case study provided the basis for reconsideration of broader issues regarding mobil-
ity and privacy.

EXTREME CASES
Cases are not always selected because they are representative or typical.
Edge cases—extreme or unusual examples—often present combinations of
characteristics that make them particularly worthy of further study. This strategy
is used extensively in medical education, where profiles of individuals with
puzzling and unusual symptoms are presented as compelling challenges for
budding diagnosticians.
As HCI researchers often use case studies as tools for understanding
the technology usage and needs of populations of potential users, these