Single case studies offer a viable alternative to large group studies such as randomized clinical trials. They involve repeated measures and manipulations of an independent variable. They can be designed to have strong internal validity for assessing causal relationships between interventions and results. They also offer external validity for the generalisability of outcomes, especially when the case study help designs include replication, randomisation and multiple participants.
In single case studies, measurements of outcome (dependent variables) are recorded repeatedly for individual participants across time and varying levels of intervention (independent variables). These varying levels of intervention are referred to as “phases”, and one of these phases serve as a baseline for comparison. It means each participant serves as his/her own control.
Advantages of Single Case Study Analysis
There is a significant lack of consensus within the wider social science literature on the principles and purposes of case study research. However, even the limited amount of study has revealed a great number of advantages of the single case study analysis approach.
Through the use application of multiple qualitative and quantitative research methods, the various forms of single case study analysis offer a nuanced, empirically rich, holistic account of specific phenomena.
Perhaps, this is particularly appropriate for those phenomena that are simply less amenable to more superficial measures and tests, as well as those which our reasons for understanding and/or explaining them are irreducibly subjective.
From different epistemological and analytical standpoints, single case study analysis can incorporate both idiographic sui generics cases and monotheistic case studies suitable for the testing and building casual hypotheses, where the potential for generalization may exist.
Lastly, we must acknowledge the fact that a signal advantage of the case study also exists at a more practical rather than a theoretical level. It is economical for all resources, including money, manpower, time, effort, etc., especially important if studies are inherently costly.
Limitations of Single Case Study Analysis
Single case study analysis has been subject to a lot of criticism over the years. Some of the major criticisms it involves are regarding the issues of methodological rigour, researcher subjectivity, and external validity.
According to Zeev Maoz, a professor of political science at the University of California, the use of the case study pardons the author from any kind of methodological considerations. He further states that such case studies have become a synonym for freeform research where anything goes.
A number of other researchers also raise a concern about the absence of systematic procedures for a case study due to the relative absence of methodological guidelines.
The next issue that happens to be a limitation to a single case study analysis is the concern regarding the reliability and replicability of different forms of this case study analysis. This issue is often tied to the larger critique of the qualitative research method as a whole.
The issue of researcher subjectivity is valid, and perhaps it is intended only as a methodological critique of what is certainly less formalized and researcher-independent methods.
It also rests on certain assumptions that can raise deeper and potentially conflicting ontological and epistemological issues. Researchers suggest that the case study contains no greater bias toward verification than other methods of inquiry. They also suggest that on the contrary, experience indicates that case study involves a greater bias toward falsification of preconceived notions than toward verification.
The most prominent critique of a single case study analysis is the issue of external validity or generalisability. It raises the question of how one case can reliably offer anything beyond the particular. Researchers suggest that we always do better with more observation as the basis of our generalisation.
Researchers further added that in all social science research and all prediction, it is important to be as explicit as possible regarding the degree of uncertainty our predictions have. This is certainly a valid criticism. Perhaps, the theories that pass a single crucial case study test require rare antecedent conditions and therefore have limited explanatory range.
According to Stephen Van Evera, professor of political science, Massachusetts Institute of Technology, these conditions may emerge more clearly from large-N studies in which cases that lack then display themselves as outliers presenting a theory’s cause but without its predicted outcome.
However, there are three major qualifiers to the argument about generalization which deserve a mention here. With regard to an idiographic single-outcome case study, the criticism is mitigated by the fact that its capability to do so is never claimed by its exponents. Criticism of generalisability is barely relevant when the intention is one of particularization.
The second qualification relates to the difference between statistical and analytical generalisation. Single case study analysis is clearly less appropriate for the former. However, it retains significant utility for the latter. Theory confirmation or disconfirmation is not exactly the strong suit of single case study analysis.
The third qualification is about the issue of case selection. The generalisability of case studies can be increased by the strategic selection of cases. Representative or random samples may not the right choice, given that they may not offer the richest insight. Instead, a properly used, atypical or extreme case often discloses more information as they activate more actors.
Conclusion
The goal for most proponents of cases studies is to overcome dichotomies between generalizing and particularizing, qualitative and quantitative, and deductive and inductive techniques. Research objectives should drive methodological choices, instead of narrow and dogmatic preconceived approaches. The inherent weakness of any one method, however, can be offset by situating them with a broader research strategy. Irrespective of the way single case studies are used, the case study has a lot to offer.
