Case Studies and Theory Development in the Social Sciences - Alexander L. George [96]
Another way in which the investigator can attempt to deal with the limitations of the congruence method is to provide a plausible or convincing argument that the deductive theory or empirical generalization being employed is powerful and well validated, that it fits the case at hand extremely well, and that it is not rivaled by competing theories or at least is better than conceivable alternative theories. By invoking the superior standing of the theory employed or by resorting to process-tracing, the investigator may be satisfied that the within-case approach suffices and need not be buttressed by across-case comparisons.
When an investigator lacks confidence in the results of the congruence method employed in the within-case mode, he or she may supplement it by making use of counterfactual analysis. That is, the investigator invents a new case that is presumably similar to the original case in every respect but one (keeping in mind the limitations of counterfactuals discussed in Chapter 8).
The next section discusses the concepts of spuriousness, causal priority, and causal depth, three possible relationships between independent and dependent variables that researchers should consider as they assess preliminary findings that the outcome in a case is congruent with a theory. The two sections that follow provide more specific advice on how researchers can assess whether a finding is spurious and whether the independent variable is a necessary condition for the outcome of the dependent variable. We then discuss how the congruence method can be used to assess the causal role of beliefs in decision-making, highlighting the difficulty of ascertaining how decision-makers come to their decisions and noting how several scholars have coped with this challenge. Finally, we consider how the congruence method can be used to add to studies of deductive theories that put a “black box” around decision-making and strategic interaction, emphasizing the usefulness of process-tracing as a way to strengthen results by identifying a causal process that could lead from the independent to the dependent variable.
Spuriousness, Causal Priority, and Causal Depth
To assess the possible causal significance of congruity in a case, the researcher should ask two questions inspired by the logic of experiment. First, is the consistency spurious or of possible causal significance? Second, is the independent variable a necessary condition for the outcome of the dependent variable, and how much explanatory or predictive power does it have? The latter question is important, since a condition may be necessary but still contribute little to the explanation or prediction of the outcome in question.
Except for tests of deterministic theories stated in terms of necessity and sufficiency, a single congruence test is not strong enough to provide confirmation or falsification of theories.381 More than one theory may be equally congruent with the outcome, or the outcome may be caused by other factors not identified by any of the theories considered. Researchers must be sensitive to the issues of spuriousness, causal priority, and causal depth in judging the strength of inferences made on the basis of congruence tests. A few comments on each of these three issues are needed. Spuriousness occurs when the observed congruence of the cause C and effect E is artificial because both C and E are caused by some third factor Z (whether or not Z has been identified in a competing theory):
Alternatively, the putative cause C lacks causal priority if C