A Case Study

It is an understatement that there is confusion among students, teachers, researchers, and methodologists about the definition and the main characteristics of case study research. Case study research is presented by some as a strictly exploratory research strategy in which nothing can be proven, most often by referring to the alleged impossibility to “generalize”. Others, such as Yin (1984, 1994, 2003), have claimed that the problem of “generalization” can be solved and that, therefore, theories can also be tested in (preferably) “multiple case studies”. A major difficulty for students and novice case study researchers is that proponents of these different perspectives give different meanings to similar methodological terms without clearly defining these meanings, making it almost impossible to grasp the nature of the debate and to infer solutions to problems in designing their own research. Ragin (1992) has argued that the work of any given case study researcher often is characterized by some hybrid of various approaches, which are usually difficult to disentangle. Most definitions of case study research, as found in the literature, are statements about the most frequently used measurement techniques (such as using “multiple sources of evidence”, or “qualitative methods”) and research objectives (such as “exploration”). Such definitions are attempts to capture in one statement the most important practical characteristics of a diverse array of studies that present themselves 1.1as case studies. Yin’s (2003: 13–14) definition is an example of such an all-inclusive descriptive definition: “A case study is an empirical inquiry that investigates a contemporary phenomenon within its real-life context, especially when the boundaries between object of study and context are not clearly evident. It copes with the technically distinctive situation in which there will be many more variables of interest than data points, and as one result relies on multiple sources of evidence, with data needing to converge in a triangulating fashion, and as another result benefits from the prior development of theoretical propositions to guide data collection and analysis”. But one methodological characteristic by which a case study is distinct from other research strategies such as the survey is not captured in Yin’s work, or most other definitions found in the literature, namely the fact that a case study basically is an inquiry of only one single instance (the case), or sometimes a small number of instances, of the object of study. Yin’s and others’ definitions only highlight another distinctive characteristic of the case study, namely that in a case study the object of study or its environment are not manipulated (“real life context”).This definition wants to capture both, and the two really distinctive features of the case study in comparison to the survey and the experiment create our definition of the case study: A case study is a study in which (a) one case (single case study) or a small number of cases (comparative case study) in their real life context are selected, and (b) scores obtained from these cases are analysed in a qualitative manner. With “study” we mean a research project in which a practice-oriented or theory-oriented research objective is formulated and achieved. With a case we mean an instance of an object of study. (We will explain our concept of “object of study” in Chapter 3.) With “real life context” we mean the object of study as it occurs (or has occurred) in reality, without manipulation. With “analysis in a qualitative manner” we mean an analysis based on visual inspection of the scores of the case (in contrast to a statistical analysis). We distinguish two main types of case study: the single case study, a case study in which data from one instance is enough to achieve the research objective, and the comparative case study, a case study that requires data from two or more instances to achieve the research objective. The difference between the experiment and the case study is that the experiment manipulates instances, whereas the case study does not. An experiment is a study in which one or more variable characteristics of an object of study are manipulated in one or multiple (“experimental”) instances of an object of study and in which scores obtained in the experimental instance or instances are analysed. The survey also studies instances in their real life context. A survey is a study in which (a) a single population in the real life context is selected, and (b) scores obtained from this population are analysed in a quantitative (statistical) manner. Our definition of the case study reflects our idea that the survey and the case study are different in two aspects; (a) the number of instances from which data are collected for the analysis, and, consequently, (b) the method of data analysis. The instances and data can be available from earlier studies (allowing for a secondary analysis) or it may be necessary to select new instances and collect new data. The case study draws conclusions on the basis of a “qualitative” analysis (“visual inspection”) of scores from one single instance (single case study) or from a small number of instances (comparative case study), whereas the survey draws conclusions on the basis of a quantitative (statistical) analysis of data from a population with a large number of instances.The definition of the case study does not include statements on data collection or measurement techniques. In our view research strategies do not differ, in principle, in terms of methods of measurement. For all three research strategies discussed here, the data analysed can be quantitative or qualitative! Measurement methods that are usually associated with case studies, such as the “qualitative” interview and using “multiple sources of evidence”, could also be used in the other research strategies. Similarly, measurement methods that are usually associated with other research strategies, such as standardized questionnaires in surveys and quantitative measurements in experiments, could also be used in case studies. Principles of measurement and the quality criteria that apply to it, such as reliability and validity, apply to any measurement in any research strategy. Although in a case study quantitative data can be used to generate the scores to be analysed, the interpretation of scores of the (small number of) cases in order to generate the outcome of the study is done qualitatively (by visual inspection) and not statistically. The definition of the case study is applicable also to the study of instances (cases) of objects of study that existed or occurred in the past. Therefore, the study of instances of an object of study as occurring “in its real-life context” (as formulated in our definition) includes both the study of contemporary instances and of past instances. In this book, thus, we discuss the case study as a research strategy defined by the number of instances (N 1 or N small) that is studied as well as the “qualitative” or non-statistical method of analysis of all kinds of (quantitative and qualitative) data.