The key term of this book is, admittedly, a definitional morass. To refer to a work as a “case study” might mean: (a) that its method is qualitative, small-N, (b) that the research is holistic, thick (a more or less comprehensive examination of a phenomenon), (c) that it utilizes a particular type of evidence (e.g., ethnographic, clinical, nonexperimental, non-survey-based, participant-observation, process-tracing, historical, textual, or field research), (d) that its method of evidence gathering is naturalistic (a “real-life context”), (e) that the topic is diffuse (case and context are difficult to distinguish), (f) that it employs triangulation (“multiple sources of evidence”), (g) that the research investigates the properties of a single observation, or (h) that the research investigates the properties of a single phenomenon, instance, or example.

Evidently, researchers have many things in mind when they talk about case study research. Confusion is compounded by the existence of a large number of near-synonyms – single unit, single subject, single case, N=1, case-based, case-control, case history, case method, case record, case work, within-case, clinical research, and so forth. As a result of this profusion of terms and meanings, proponents and opponents of the case study marshal a wide range of arguments but do not seem any closer to agreement than when this debate was first broached several decades ago. Jennifer Platt notes that “much case study theorizing has been conceptually confused, because too many different themes have been packed into the idea ‘case study.’”