Students ask: What is a case study?
One of the ironies of academia that, in a realm that strives for precision and rigour, we routinely confuse ourselves by using imprecise language about methods and methodology.
To be clear, methods are techniques or procedures used in research. Methodology is the alignment of method to purpose, via explicit rationale or justification that addresses relevant assumptions and constraints (cf. the 1-2-3 of research design).
There are understandable reasons for the emergence of imprecision, such as interpretations within different disciplines, and ‘language drift’ over time and across usage by many different people. For example, a term may be used as a ‘shorthand’ reference for something more complex, allowing the term to proliferate without continual anchoring in the more complex ‘something’ to which it refers. As more people use the ‘shorthand’, different users infer their own meanings, and if the ambiguity of the ‘shorthand’ and the resulting variations are not detected, they may proliferate over time, creating confusion. Even after the ambiguity is addressed and resolved, it may persist, because the prior usage is still on record.
The confusion about ‘case study methodology’ is a potent example.
A case study is, simply, a study of a case. Normally, a case study is a detailed examination in situ of a specific case (or example) of some phenomenon of interest. Usually we use case studies when we need to look at something in depth and in context (hence the association with the term ‘naturalistic’), and so the examination/exploration is likely to address different aspects or facets of the case. (In that sense, one can refer loosely to a ‘case study approach’.) Note that multiple facets implies multiple methods and hence multiple sources and types of evidence – all of which need to be specified and justified.
On its own, a case study is neither a methodology, nor a method. Each case study is conducted for a purpose, with a phenomenon or question in mind, which must be articulated. (And each is conducted within – and hence influenced by – some disciplinary and epistemological framing.) Yin (1984) defines the case study research method “as an empirical inquiry that investigates a contemporary phenomenon within its real-life context; when the boundaries between phenomenon and context are not clearly evident; and in which multiple sources of evidence are used.” (p. 23) Each case study requires decisions about which methods will be used for that examination to select, collect, record, and analyse data (i.e., multiple sources of evidence) in order to address the specified purpose or question.
There is an inherent tension in the case study: the need to study something in detail, in context, means that the observations cannot be assumed to generalize to other contexts (hence limiting the ‘contribution to knowledge’).
One of the ways people attempt to address that limitation is to apply consistent methods across a number of case studies, in the hope of finding patterns of interest – or to identify the range of variation. (This is sometimes called a ‘case study approach’ [note the contrast to the more general usage flagged earlier], or ‘cross-case’ studies.) Again, there is a need to articulate the purpose; to make well-grounded and justified decisions about which methods to use, what data to collect, and how to conduct the analysis; to make well-grounded and justified decisions about which cases to study; to conduct the studies according to that protocol; and to be frank in the consideration of limitations and potential bias.
Why we need to study something in-depth and in context is crucial. It shapes our expectations and decisions. Yin identifies three types of case studies: exploratory (e.g., discovering what’s worth further study, identifying questions), descriptive (e.g., describing characteristics or features of interest – often in terms of a theory), explanatory (e.g., attempting to find patterns within the data indicating causality). Yin also cautions against separating these categories, but they do highlight the need to make purpose explicit. And of course others identify different categories (e.g., evaluation, such as the application of a theory to see if it is sufficient to explain observed behaviours) contributing to further terminological muddle.
The selection of ‘cases’ is important and must align with the purpose, e.g.: selected to represent the range of variation, selected as ‘typical’, selected as exceptional (i.e., rare and significant, such as the effects of a singular catastrophe), selected as inspirational (i.e., what makes this case so distinctive and how can we learn from it?). And the analysis must be alert to contradictory, as well as confirmatory, evidence across cases.
A ‘case study approach’ implies that:
– there is a need to study some phenomenon as it occurs in the world,
– that one or more ‘case studies’ will be undertaken to do so.
However, a ‘case study approach’ is ill-defined, and the confusion about terminology emphasises the importance of complete and explicit reporting, including:
- the purpose and the desired outcome of the study (e.g., description, identification of patterns, understanding the nature of variation, identifying better research questions, generating hypotheses, generating theory, demonstration of concept, evaluation of theory…);
- what methods will be used for that study, to select, collect, and analyse data;
- establishing the appropriateness of the selected methods to address the research question (within the given theoretical framing, which should be explicit);
- consideration of potential limitations and bias;
- the disciplinary and epistemological framing (which may influence choices, analysis, and interpretation);
- documenting the appropriate execution of protocol;
- documenting the audit trail: making the ‘chain of evidence’ explicit, from data collection, through processing and analysis, to interpretation and conclusions.
To add to the confusion, sometimes the term ‘case study’ is used to mean ‘an (illustrative) example’, often to demonstrate a theory or how it might be applied. At best, that illustrative example may be explored systematically. However, this is a rhetorical method – not an empirical research method.
As ‘case study’ illustrates, this sort of terminological confusion is inevitable, and it is why the explicit definition of terms and the clear explanation of research design choices are so important.
 Presented in Chapter 8 of The Unwritten Rules of PhD Research: 1 – What’s the question/what do you want to know? 2 – What evidence will answer the question? 3 – What methods will produce the required evidence?
 Yin, R., (1984). Case study research: Design and methods. Sage.
Thank you, Marian.
Is it reasonable to say that a case study that has a negative result is more informative than a case study that has a positive result?
I am thinking of a result that states “some A are F” that it is not possible to generalise to “All A are F”. Instead, “some A are not F” generalises to “not all A are F”.
Also it is not clear to me how it is possible to use a descriptive case study in the overall argument of a thesis.