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A case study is a particular method of qualitative research. Rather than using large samples and following a rigid protocol to examine a limited number of variables, case study methods involve an in-depth, longitudinal examination of a single instance or event: a case. They provide a systematic way of looking at events, collecting data, analyzing information, and reporting the results. As a result the researcher may gain a sharpened understanding of why the instance happened as it did, and what might become important to look at more extensively in future research. Case studies lend themselves especially to generating (rather than testing) hypotheses.

The scope and relevance of case studies

Certain disciplines thrive on case studies: others find them less suitable in given situations. Compare usage and perceived validity in the humanities, natural sciences, social sciences, pseudoscience and business.

Rogers, in Business Analysis for Marketing Managers (1978) distinguishes case studies from case histories and projects. He describes a case history as an event or series of events set in an organisational framework with or without a related environment. The events are described in some detail with the main and subsidiary points highlighted. Actions taken by subjects in the case are described; reactions, responses and effects on other subjects are related, and events taken to a conclusion or to a point that is irreversible. Medical cases are typical of the category. Symptoms are described, probable and possible causes suggested, treatment recommended, prognosis recorded, and the date when the patient was discharged or buried.

He defined the case study as also describing events in a framework within an environment. The problems are not always highlighted or even made clear; they emerge as the case material is subjected to analysis. A conclusion is not necessarily stated nor is the situation reached in the case irreversible. It is usually possible to ‘take over’ operations at a suitable point in the role of an external adviser or from a position in the case. Most business cases fall into this category.

The case project is a series of diverse continuous events, set in an organizational framework and normally in a well-defined environment. Those studying the case are led to a specific point in time and circumstance where they become a ‘participant’ in the case. They may be asked to assume the role of a person in the case, appointed to a particular vacancy, or to advise from the position of an external consultant. The role is made explicit and it is from that viewpoint that analysis, views, arguments and recommendations must be made; there is thus a behavioural aspect introduced. If placed in the position of a newly appointed middle manager, responses and suggestions are likely to be different from those of an external consultant. Rogers developed the case project in 1966 for the Chartered Institute of Marketing’s diploma final open book examination. To avoid pre-prepared scripts being submitted, the examination paper progressed the case by several months from when it was published, introducing new material. This required candidates to modify the analyses and conclusions already reached and write a true examination room report.

Types of case study

Illustrative case studies

Illustrative case studies describe a domain; they use one or two instances to analyze a situation. This helps interpret other data, especially when researchers have reason to believe that readers know too little about a program. These case studies serve to make the unfamiliar familiar, and give readers a common language about the topic. The chosen site should typify important variations and contain a small number of cases to sustain readers' interest.

The presentation of illustrative case studies may involve some pitfalls. Such studies require presentation of in-depth information on each illustration; but the researcher may lack time on-site for in-depth examination. The most serious problem involves the selection of instances. The case(s) must adequately represent the situation or program. Where significant diversity exists, no single individual site may cover the field adequately..

Exploratory case studies

Exploratory case studies condense the case study process: researchers may undertake them before implementing a large-scale investigation. Where considerable uncertainty exists about program operations, goals, and results, exploratory case studies help identify questions, select measurement constructs, and develop measures; they also serve to safeguard investment in larger studies.

The greatest pitfall in the exploratory study involves premature conclusions: the findings may seem convincing enough for inappropriate release as conclusions. Other pitfalls include the tendency to extend the exploratory phase, and inadequate representation of diversity.

Critical instance case studies

Critical instance case studies examine one or a few sites for one of two purposes. A very frequent application involves the examination of a situation of unique interest, with little or no interest in generalizability. A second, rarer, application entails calling into question a highly generalized or universal assertion and testing it by examining one instance. This method particularly suits answering cause-and-effect questions about the instance of concern.

Inadequate specification of the evaluation question forms the most serious pitfall in this type of study. Correct application of the critical instance case study crucially involves probing the underlying concerns in a request.

Program implementation case studies

Program implementation case studies help discern whether implementation complies with intent. These case studies may also prove useful when concern exists about implementation problems. Extensive, longitudinal reports of what has happened over time can set a context for interpreting a finding of implementation variability. In either case, researchers aim for generalization and must carefully negotiate the evaluation questions with their customer.

Good program implementation case studies must invest sufficient time to obtain longitudinal data and breadth of information. They typically require multiple sites to answer program implementation questions; this imposes demands on training and supervision needed for quality control. The demands of data management, quality control, validation procedures, and analytic modelling (within site, cross-site, etc.) may lead to cutting too many corners to maintain quality.

Program effects case studies

Program effects case studies can determine the impact of programs and provide inferences about reasons for success or failure. As with program implementation case studies, the evaluation questions usually require generalizability and, for a highly diverse program, it may become difficult to answer the questions adequately and retain a manageable number of sites. But methodological solutions to this problem exist. One approach involves first conducting the case studies in sites chosen for their representativeness, then verifying these findings through examination of administrative data, prior reports, or a survey. Another solution involves using other methods first. After identifying findings of specific interest, researchers may then implement case studies in selected sites to maximize the usefulness of the information.

Cumulative case studies

Cumulative case studies aggregate information from several sites collected at different times. The cumulative case study can have a retrospective focus, collecting information across studies done in the past, or a prospective outlook, structuring a series of investigations for different times in the future. Retrospective cumulation allows generalization without cost and time of conducting numerous new case studies; prospective cumulation also allows generalization without unmanageably large numbers of cases in process at any one time.

The techniques for ensuring sufficient comparability and quality and for aggregating the information constitute the "cumulative" part of the methodology. Features of the cumulative case study include the case survey method (used as a means of aggregating findings) and backfill techniques. The latter aid in retrospective cumulation as a means of obtaining information from authors that permits use of otherwise insufficiently detailed case studies.

Opinions vary as to the credibility of cumulative case studies for answering program implementation and effects questions. One authority notes that publication biases may favor programs that seem to work, which could lead to a misleading positive view (Berger, 1983). Others raise concerns about problems in verifying the quality of the original data and analyses (Yin, 1989).

Business school case studies

Case studies have been used in graduate and undergraduate business education for nearly one hundred years. Business cases are historical descriptions of actual business situations. Typically, information is presented about a business firm's products, markets, competition, financial structure, sales volumes, management, employees and other factors affecting the firm's success. The length of a business case study may range from two or three pages to 30 pages, or more.

Leading exponents of the case study method of instruction include the Harvard Business School, the Darden School (University of Virginia), the Tuck School (Dartmouth), Stanford University Business School, Ivey School (University of Western Ontario) and INSEAD (France and Singapore). Examples of widely used case studies are "Lincoln Electric" and "Google, Inc.," both published by the Harvard Business School.

Students are expected to scrutinize the case study and prepare to discuss strategies and tactics that the firm should employ in the future.

Three different methods have been used in business case teaching: (1) prepared case-specific questions to be answered by the student, (2) problem-solving analysis and (3) a generally applicable strategic planning approach.

The first method listed above is used with short cases intended for undergraduate students. The underlying concept is that such students need specific guidance to be able to analyze case studies.

The second method, initiated by the Harvard Business School is by far the most widely used method in MBA and executive development programs. The underlying concept is that with enough practice (hundreds of case analyses) students develop intuitive skills for analyzing and resolving complex business situations. Click here for more information on the HBS case method. Successful implementation of this method depends heavily on the skills of the discussion leader. Only a few teachers are able to become truly great case discussion leaders. Jim Erskine at the Ivey School is a prime example of such a teacher.

The third method does not require students to analyze hundreds of cases. A strategic planning model is provided and students are instructed to apply the steps of the model to six to a dozen cases during a semester. This is sufficient to develop their ability to analyze a complex situation, generate a variety of possible strategies and to select the best ones. In effect, students learn a generally applicable approach to analyzing cases studies and real situations. This approach does not make any extraordinary demands on the artistic and dramatic talents of the teacher. Consequently most professors are capable of supervising application of this method.

Medical case studies

In medical science case studies are considered "Class V" evidence, and are thus the least suggestive of all forms of medical evidence.[1]

History of the case study

As a distinct approach to research, use of the case study originated only in the early 20th century. The Oxford English Dictionary traces the phrase case study or case-study back as far as 1934, after the establishment of the concept of a case history in medicine.

The use of case studies for the creation of new theory in social sciences has been further developed by the sociologists Barney Glaser and Anselm Strauss who presented their research method, Grounded theory, in 1967.

The popularity of case studies as research tools has developed only in recent decades. One of the areas in which case studies have been gaining popularity is education and in particular educational evaluation. Some of the prominent scholars in educational case study are Robert Stake and Jan Nespor (see references). Case studies have, of course, also been used as a teaching method and as part of professional development. They are well-known in business and legal education. The problem-based learning (PBL) movement is one of the examples. When used in (non-business) education and professional development, case studies are often referred to as critical incidents (see David Tripp in references).

History of Business Cases. - When the Harvard Business School was started, the faculty quickly realized that there were no textbooks suitable to a graduate program in business. Their first solution to this problem was to interview leading practioners of business and to write detailed accounts of what these managers were doing. Of course the professors could not present these cases as practices to be emulated because there were no criteria available for determining what would succeed and what would not succeed. So the professors instructed their students to read the cases and to come to class prepared to discuss the cases and to offer recommendations for appropriate courses of action. Basically that is the model still being used. See a critique of this approach.


The case study offers a method of learning about a complex instance through extensive description and contextual analysis. The product articulates why the instance occurred as it did, and what one might usefully explore in similar situations.

Case studies can generate a great deal of data that may defy straightforward analysis. For details on conducting a case study, especially with regard to data collection and analysis, see the references listed below.

Notable case studies

  • Street Corner Society by William Foote Whyte, 1943, a descriptive case study of an Italian slum district in Boston, Massachusetts in the late 1930s.
  • Essence of Decision: Explaining the Cuban Missile Crisis is an analysis by Graham T. Allison, 1971, an explanatory case study of the Cuban Missile Crisis contrasting three different theories of decision making: rational actor, organizational process, and governmental politics.
  • Weick, Karl E. (1993). The Collapse of Sensemaking in Organizations: The Mann Gulch Disaster. Administrative Science Quarterly 38: 628–652. — Analyzes various problems of group behavior under high pressure (e.g. group think) based on the Mann Gulch fire.

See also


  • Berger, Michael A. "Studying Enrollment Decline (and Other Timely Issues) via the Case Survey." Educational Evaluation and Policy Analysis, 5:3 (1983), 307-317.
  • Datta, Lois-ellin (1990). Case Study Evaluations. Washington, DC: U.S. General Accounting Office, Transfer paper 10.1.9.
  • Miles, Matthew B., and Huberman, A.M. (1984). Qualitative Data Analysis: A Sourcebook of New Methods. Beverly Hills, CA: Sage.
  • Nespor, Jan (1994) Knowledge in motion: space, time, and curriculum in undergraduate physics and management. London, Falmer Press.
  • Rogers, L.A. (1978) Business Analysis for Marketing Managers. London, Heinemann.
  • Stake, Robert E. (1995) The art of case study research. Thousand Oaks, Calif., London, Sage.
  • Tripp, David (1993) Critical incidents in teaching: developing professional judgement. London: Routledge.
  • Yin, Robert K. (1989). Case Study Research: Design and Methods. Beverly Hills, CA: Sage.

External links


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