Qualitative inquiry

Flyvbjerg / Inquiry
Qualitative Case-Study Research Misunderstandings
10.1177/1077800405284363

Five Misunderstandings
About Case-Study
Research

Qualitative Inquiry
Volume 12 Number 2
April 2006 219-245
© 2006 Sage Publications
10.1177/1077800405284363
http://qix.sagepub.com
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Bent Flyvbjerg
Aalborg University, Denmark
This article examinesfive common misunderstandings about case-study
research: (a) theoretical knowledge is more valuable than practical knowledge;
(b) one cannot generalize from a single case, therefore, the single-case study
cannot contribute to scientific development; (c) the case study is most useful
for generating hypotheses, whereas other methods are more suitable for
hypotheses testing and theory building;(d) the case study contains a bias
toward verification; and (e) it is often difficult to summarize specific case studies. This article explains and corrects these misunderstandings one by one and
concludes with the Kuhnian insight that a scientific discipline without a large
number of thoroughly executed case studies is a discipline without systematic
production of exemplars, and a disciplinewithout exemplars is an ineffective
one. Social science may be strengthened by the execution of a greater number
of good case studies.
Keywords:

case study; case selection; critical cases; validity in case studies

W

hen I first became interested in in-depth case-study research, I was
trying to understand how power and rationality shape each other and
form the urban environments inwhich we live (Flyvbjerg, 1998). It was clear
to me that to understand a complex issue such as this, in-depth case-study
research was necessary. It was equally clear, however, that my teachers and
colleagues kept dissuading me from employing this particular research
methodology.
“You cannot generalize from a single case,” some would say, “and social
science is about generalizing.” Others wouldargue that the case study may be
well suited for pilot studies but not for full-fledged research schemes. Others
again would comment that the case study is subjective, giving too much
scope for the researcher’s own interpretations. Thus, the validity of case
studies would be wanting, they argued.
At first, I did not know how to respond to such claims, which clearly
formed the conventionalwisdom about case-study research. I decided, there-

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fore, to find out where the claims come from and whether they are correct.
This article contains what I discovered.

The Conventional Wisdom About Case-Study Research
Looking up case study in the Dictionary of Sociology as a beginning, I
found the following in full citation:
Case Study. The detailedexamination of a single example of a class of phenomena, a case study cannot provide reliable information about the broader
class, but it may be useful in the preliminary stages of an investigation since it
provides hypotheses, which may be tested systematically with a larger number
of cases. (Abercrombie, Hill, & Turner, 1984, p. 34)1

This description is indicative of the conventional wisdom ofcase-study
research, which if not directly wrong, is so oversimplified as to be grossly
misleading. It is correct that the case study is a “detailed examination of a single example,” but as we see below, it is not true that a case study “cannot provide reliable information about the broader class.” It is also correct that a case
study can be used “in the preliminary stages of an investigation”to generate
hypotheses, but it is misleading to see the case study as a pilot method to be
used only in preparing the real study’s larger surveys, systematic hypotheses
testing, and theory building.
According to the conventional view, a case and a case study cannot be of
value in and of themselves; they need to be linked to hypotheses, following
the well-known hypothetico-deductive model...