Case study


In the social and life sciences, a case study is a research method involving an up-close, in-depth, and detailed examination of a particular case. For example, a case study in medicine may examine a specific patient a doctor treated, and a case study in business might study a particular firm's strategy. Generally, a case can be nearly any unit of analysis, including individuals, organizations, events, or actions.
Case studies can be produced by following a formal research method. These case studies are likely to appear in formal research venues, as journals and professional conferences, rather than in popular works. Case study research can mean single and multiple case studies, can include quantitative evidence, relies on multiple sources of evidence, and benefits from the prior development of theoretical propositions. Case studies may involve both qualitative and quantitative research methods. Single-subject research provides the statistical framework for making inferences from quantitative case-study data. Another suggestion is that case study should be defined as a "research strategy", an empirical inquiry that investigates a phenomenon within its real-life context. A case study does not necessarily have to be N=1, as there may be many observations within a case.
The resulting body of 'case study research' has long had a prominent place in many disciplines and professions, ranging from psychology, anthropology, sociology, and political science to education, clinical science, social work, and administrative science. Case study research have also played a prominent place in business and management research.

Research methods

In business research, four common case study approaches are distinguished. First, there is the "no theory first" type of case study design, which is closely connected to Kathleen M. Eisenhardt's methodological work. The second type of research design is about "gaps and holes", following Robert K. Yin's guidelines and making positivist assumptions. A third design deals with a "social construction of reality", represented by the work of Robert E. Stake. Finally, the reason for case study research can also be to identify "anomalies"; a representative scholar of this approach is Michael Burawoy. Each of these four approaches has its areas of application, but it is important to understand their unique ontological and epistomological assumptions. There are substantial methodological differences between these approaches.

Case selection and structure

An average, or typical case, is often not the richest in information. In clarifying lines of history and causation it is more useful to select subjects that offer an interesting, unusual or particularly revealing set of circumstances. A case selection that is based on representativeness will seldom be able to produce these kinds of insights. When selecting a case for a case study, researchers will therefore use information-oriented sampling, as opposed to random sampling. Outlier cases reveal more information than the potentially representative case, as seen in cases selected for more qualitative safety scientific analyses of accidents. A case may be chosen because of the inherent interest of the case or the circumstances surrounding it. Alternatively it may be chosen because of researchers' in-depth local knowledge; where researchers have this local knowledge they are in a position to "soak and poke" as Richard Fenno put it, and thereby to offer reasoned lines of explanation based on this rich knowledge of setting and circumstances.
Three types of cases may thus be distinguished for selection:
  1. Key cases
  2. Outlier cases
  3. Local knowledge cases
Whatever the frame of reference for the choice of the subject of the case study, there is a distinction to be made between the subject and the object of the case study. The subject is the "practical, historical unity" through which the theoretical focus of the study is being viewed. The object is that theoretical focus – the analytical frame. Thus, for example, if a researcher were interested in US resistance to communist expansion as a theoretical focus, then the Korean War might be taken to be the subject, the lens, the case study through which the theoretical focus, the object, could be viewed and explicated.
Beyond decisions about case selection and the subject and object of the study, decisions need to be made about purpose, approach and process in the case study. Gary Thomas thus proposes a typology for the case study wherein purposes are first identified, then approaches are delineated, then processes are decided upon, with a principal choice being between whether the study is to be single or multiple, and choices also about whether the study is to be retrospective, snapshot or diachronic, and whether it is nested, parallel or sequential.
John Gerring and Jason Seawright list seven case selection strategies:
  1. Typical cases – cases that exemplify a stable cross-case relationship. These cases are representative of the larger population of cases, and the purpose of the study is to look within the case rather than compare it with other cases
  2. Diverse cases – cases that have variation on the relevant X and Y variables. Due to the range of variation on the relevant variables, these cases are representative of the full population of cases.
  3. Extreme cases – cases that have an extreme value on the X or Y variable relative to other cases
  4. Deviant cases – cases that defy existing theories and common sense. They not only have extreme values on X or Y, but defy existing knowledge about causal relations
  5. Influential cases – cases that are central to a model or theory
  6. Most similar cases – Cases that are similar on all the independent variables, except the one of interest to the researcher
  7. Most different cases – Cases that are different on all the independent variables, except the one of interest to the researcher
Arend Lijphart, and Harry Eckstein identified five types of case study research designs, Alexander George and Andrew Bennett added a sixth category:
  1. Atheoretical case studies – the goal is to describe a case very well, but not to contribute to a theory.
  2. Interpretative case studies – the goal is to use established theories to explain a specific case
  3. Hypothesis-generating case studies – the goal is to inductively identify new variables, hypotheses, causal mechanisms and causal paths.
  4. Theory testing case studies – the goal is to assess the validity and scope conditions of existing theories.
  5. Plausibility probes – the goal is to assess the plausibility of new hypotheses and theories
  6. Building block studies of types or subtypes – the goal is to identify common patterns across cases
In terms of case selection, Gary King, Robert Keohane, and Sidney Verba warn against "selecting on the dependent variable". For example, researchers cannot make valid causal inferences about war outbreak by only looking at instances where war did happen. There is no methodological problem in selecting on the explanatory variable, however. They do warn about multicollinearity. While random selection of cases is a valid case selection strategy in large-N research, there is a consensus among scholars that it risks generating serious biases in small-N research.
In public-relations research, three types of case studies are used:
  1. Linear,
  2. Process-oriented,
  3. Grounded.
Under the more generalized category of case study exist several subdivisions, each of which is custom selected for use depending upon the goals of the investigator. These types of case study include the following:
Some cases study marketing analysis to ensure a full understanding of the effects on an organization. In a case where the market of any organization is in jeopardy, the agency will seek answers and solutions. In order to fulfill this need, the organization must gather pertinent information. Case studies can be used to establish where the problem originates by utilizing several research methods. Research methods should be chosen appropriately to conduct a thorough investigation. The primary methods used include: interviews, surveys, focus groups, observations and in some cases, field trials. The methods chosen rely heavily on the amount of capital the organization is able to spend and the kind of data that is required by the group.

In business

At Harvard Law School In 1870, Christopher Langdell departed from the traditional lecture-and-notes approach to teaching contract law and began using cases pled before courts as the basis for class discussions. By 1920, this practice had become the dominant pedagogical approach used by law schools in the United States.
Research in business disciplines is usually based on a positivist epistemology, namely, that reality is something that is objective and can be discovered and understood by a scientific examination of empirical evidence. But organizational behavior cannot always be easily reduced to simple tests that prove something to be true or false. Reality may be an objective thing, but it is understood and interpreted by people who, in turn, act upon it, and so critical realism, which addresses the connection between the natural and social worlds, is a useful basis for analyzing the environment of and events within an organization.
Case studies in management are generally used to interpret strategies or relationships, to develop sets of "best practices", or to analyze the external influences or the internal interactions of a firm. With several notable exceptions

History

first introduced the case-study method into social science in 1829 as a handmaiden to statistics in his studies of family budgets.
In all these disciplines, case studies were an occasion for postulating new theories, as in the grounded-theory work of sociologists Barney Glaser and Anselm Strauss.
One of the areas in which case studies have been gaining popularity is education and in particular educational evaluation.
Comparative case studies, in social science, policy, and education research; discusses one approach, which encourages researchers to compare horizontally, vertically, and temporally.

Uses and limits

Uses

Case studies have commonly been seen as a fruitful way to come up hypotheses and generate theories. Case studies are also useful for formulating concepts, which are an important aspect of theory construction. The concepts used in qualitative research will tend to have higher conceptual validity than concepts used in quantitative research. Case studies add descriptive richness. Through fine-grained knowledge and description, case studies can fully specify the causal mechanisms in a way that may be harder in a large-N study. Case studies of cases that defy existing theoretical expectations may contribute knowledge by delineating why the cases violate theoretical predictions and specifying the scope conditions of the theory. Alexander George and Andrew Bennett argue that case studies are very useful in situations of causal complexity where there is equifinality, complex interaction effects and path dependency. They argue that case studies may also be useful in identifying the scope conditions of a theory: whether variables are sufficient or necessary to bring about an outcome.
Using case studies in research differs from their use in teaching, where they are commonly called case methods and casebook methods. Teaching case studies have been a highly popular pedagogical format in many fields ranging from business education to science education. Harvard Business School has been among the most prominent developers and users of teaching case studies. Business school faculty generally develop case studies with particular learning objectives in mind. Additional relevant documentation, such as financial statements, time-lines, and short biographies, often referred to in the case study as exhibits, and multimedia supplements often accompany the case studies. Similarly, teaching case studies have become increasingly popular in science education. The National Center for Case Studies in Teaching Science has made a growing body of case studies available for classroom use, for university as well as secondary school coursework.
Case studies are commonly used in case competitions and in job interviews for consulting firms such as McKinsey & Company, CEB Inc. and the Boston Consulting Group, in which candidates are asked to develop the best solution for a case in an allotted time frame.

Limits

Designing Social Inquiry, an influential 1994 book written by Gary King, Robert Keohane, and Sidney Verba, primarily applies lessons from regression-oriented analysis to qualitative research, arguing that the same logics of causal inference can be used in both types of research. The authors' recommendation is to increase the number of observations, because few observations make it harder to estimate multiple causal effects, more likely that there is measurement error, and risks that an event in a single case was caused by random error. KKV sees process-tracing and qualitative research as being "unable to yield strong causal inference" due to the fact that qualitative scholars would struggle with determining which of many intervening variables truly links the independent variable with a dependent variable. The primary problem is that qualitative research lacks a sufficient number of observations to properly estimate the effects of an independent variable. They write that the number of observations could be increased through various means, but that would simultaneously lead to another problem: that the number of variables would increase and thus reduce degrees of freedom.
A commonly described limit of case studies is that they do not lend themselves to generalizability. Some scholars, such as Bent Flyvbjerg, have pushed back on that notion.
As small-N research should not rely on random sampling, scholars must be careful in avoiding selection bias when picking suitable cases. A common criticism of qualitative scholarship is that cases are chosen because they are consistent with the scholar's preconceived notions, resulting in biased research.
Alexander George and Andrew Bennett note that a common problem in case study research is that of reconciling conflicting interpretations of the same.