Comparative Case Studies

Structured and Focused Comparison

• “First, the investigator should clearly identify the universe—that is, the “class” or “subclass” of events—of which a single case or a group of cases to be studied are instances. “

• “Second, a well-defined research objective and an appropriate research strategy to achieve that objective should guide the selection and analysis of a single case or several cases within the class or subclass of the phenomenon under investigation. Cases should not be chosen simply because they are “interesting” or because ample data exist for studying them.”

• “Third, case studies should employ variables of theoretical interest for purposes of explanation. These should include variables that provide some leverage for policymakers to enable them to influence outcomes.”

• Structured: “From the statistical (and survey) research model, the method of structured, focused comparison borrows the device of asking a set of standardized, general questions of each case, even in single case studies. These questions must be carefully developed to reflect the research objective and theoretical focus of the inquiry. The use of a set of general questions is necessary to ensure the acquisition of comparable data in comparative studies.”

• Focused: “The method also requires that the study of cases be “focused”: that is, they should be undertaken with a specific research objective in mind and a theoretical focus appropriate for that objective. A single study cannot address all the interesting aspects of a historical event.”

Phase One: Designing Case Study Research

Task One: Specification of the Problem and Research Objective

Task Two: Developing a Research Strategy: Specification of Variables

• “What exactly and precisely is the dependent (or outcome) variable to be explained or predicted?”

• “What independent (and intervening) variables comprise the theoretical framework of the study?”

• “Which of these variables will be held constant (serve as parameters) and which will vary across cases included in the comparison?” (George and Bennet, 2005)

Task Three: Case Selection

• “ One should select cases not simply because they are interesting, important, or easily researched using readily available data. Rather, case selection should be an integral part of a good research strategy to achieve well-defined objectives of the study. Hence the primary criterion for case selection should be relevance to the research objective of the study, whether it includes theory development, theory testing, or heuristic purposes.”

• “ Researchers can be somewhat opportunistic here—they may come across a pair of well matched before-after cases or a pair of cases that closely fit “most similar” or “least similar” case research designs. They may also come upon cases that have many features of a most- or least-likely case, a crucial case, or a deviant case.”

• “Often researchers begin their inquiry with a theory in search of a test case or a case in search of a theory for which it is a good test. Either approach is viable, provided that care is taken to prevent case selection bias and, if necessary, to study several cases that pose appropriate tests for a candidate theory once one is identified.”

Task Four: Describing the Variance in Variables

• Analogous to measurement in quantitative studies

• What and how many categories should be established to describe variation?

• May not be best to firmly establish prior to the study but rather by an iterative process.

Task Five: Formulation of Data Requirements and General Questions

• “The case study method will be more effective if the research design includes a specification of the data to be obtained from the case or cases under study. Data requirements should be determined by the theoretical framework and the research strategy to be used for achieving the study’s research objectives.”

• “…specification of the data requirements should take the form of general questions to be asked of each case. This is a way of standardizing data requirements so that comparable data will be obtained from each case and so that a single-case study can be compared later with others.”

• “Asking the same questions of each case does not prevent the case writer from addressing more specific aspects of the case or bringing out idiosyncratic features of each case that may also be of interest for theory development or future research.”

• “The general questions must reflect the theoretical framework employed, the data that will be needed to satisfy the research objective of the study, and the kind of contribution to theory that the researcher intends to make. In other words, a mechanical use of the method of structured, focused comparison will not yield good results. The proper focusing and structuring of the comparison requires a fine-tuned set of general questions that are integrated with the four other elements of the research design.”