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172 CHAPTER 7 Case studies

A study of sociability in massive, multiplayer, online games provides another
example of the important role of theory in case study design. In Ducheneaut et al.
(2007), the researchers were interested in asking whether social spaces in these
games acted as “third spaces,” where players would socialize, just as coffee shops
and other spaces support socializing in the real world. This question led them to
choose a particular online game that provided strong support for social spaces, a data
collection strategy involving active participation in these spaces in the game, and an
analysis strategy that combined analysis of observations from their participation with
quantitative analysis of activity in the game.
Once you have defined your questions and hypotheses, you can move on to con-
sider other questions of case study design, including the type of case study, selection
of cases, data collection, and data analysis.

7.7 CHOOSING CASES

Single-case studies may present little, if any, difficulty in case selection. Case studies
often involve cases that are somehow unique or incomparable to others. Intrinsic case
studies limit you to consideration of the specific instance of interest. Convenience
can also be a factor—you may choose a specific case “because it's there.” This is
often the case when you are not particularly concerned about generalizing: when
conducting an exploratory case study aimed at building initial understandings of a
situation, any case might work (see Section 7.11). In all of these instances, selection
is straightforward: you work with what you have available. Otherwise, you will want
to put careful consideration into your criteria for selecting cases.
There are a few general guidelines that apply to almost any sort of case study.
Like ethnographic investigations (Chapter 9), case studies require a great deal of
time, careful preparation, and often close cooperation with one or more individuals
or organizations. Given these challenges, the individuals, groups, organizations, or
systems that you choose should be chosen carefully. You will want to try to iden-
tify case study participants who have an interest in committing some of their own
resources to work with you to make the research successful. You should also try
to maximize convenience, working with geographically convenient participants
whenever possible.
Further considerations in your choice of cases will be driven by the details of your
research design. If you are conducting an instrumental case study aimed at develop-
ing generalizable models of classes of users or contexts, you should aim for cases
that are representative in the appropriate aspects. Although the analysis tools may be
different, this is the same problem faced by quantitative user studies (see Chapter 2):
if the participants in your study are sufficiently different from the group to which you
are generalizing, your findings may not hold up, no matter how strong the analysis.
Thus, if you are doing a case study to understand how technically unsophisticated us-
ers interact with antispyware and antivirus tools, you probably don't want to ask com-
puter science undergraduates, who are likely to be more technically savvy than most