Plausibility

Conceptual Overview and Discussion

Plausibility in case study research depends on the purpose of the study or the philosophical orientation of the researcher, who may be conducting the study from a positivistic, interpretive, or critical perspective. Positivistic research studies are intended to produce generalizable theories, interpretive studies are intended to provide deeper understandings of a particular case, and critical studies look at the specifics of a case and how they are connected to broader societal structures to expose issues of power and domination. Critical researchers sometimes use elements of positivistic and interpretive research; therefore, this discussion is limited to considering plausibility as it relates to the two most common types of research: positivist and interpretive.

In their pursuit of theory, positivist case study researchers often want to determine whether conducting a case study is worth the time, effort, and money. Harry Eckstein proposes that researchers probe the plausibility of various hypotheses that have been formulated regarding a particular issue before proceeding directly to test them through a large-scale case study or comparative studies. He compares plausibility probes to the trials to which one subjects a racehorse before incurring costs of entry and preparing a horse for a major race. At a minimum, a plausibility probe can be accomplished by nonempirical means, which entails only the cost of thought to consider whether a theory is worth investigating at all. Alternatively, empirical probes can also be conducted on a small scale, which might result in inconclusive but nevertheless suggestive results that warrant further investigation through larger scale studies.

Closely related to the idea of plausibility is validity, which refers to the strength of a proposition or inference. Plausibility can mean more than potentially valid hypotheses but less than actual validity, for which rigorous testing is required. Plausibility probes, therefore, may point to the need to test the validity of a theory.

Clyde Mitchell also differentiates between plausibility and validity, although his notion of plausibility is quite different. Plausibility to him means the inference of a logical relationship between characteristics of the sample population in a study. For example, Mitchell describes how the validity of an inference may be statistically sound but not plausible. To make the point he cites a study conducted by Asher I. Sapolsky that describes how 61% of respondents with dietary eating disorders saw a frog in a Rorschach inkblot test compared with only 16% of those without an eating disorder. On the basis of the statistical evidence, Sapolsky inferred that the reason the respondents with eating disorders saw a frog was because of their unconscious belief in the cloacal theory of birth, which involves oral impregnation and anal parturition, seen in cloacal animals such as frogs. Although Sapolsky's conclusion that more respondents with eating disorders saw a frog in the inkblot test was supported statistically, his explanation of the causal links was deemed illogical or not plausible by other scientists.

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