Case Studies and Theory Development in the Social Sciences - Alexander L. George [220]
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Bailey, following Lazarsfeld, suggests eliminating all empty cells. See Typologies and Taxonomies, p. 27. Lazarsfeld termed this process “functional reduction.” In our view, such reduction should not be automatic, as the researcher must first consider whether the theory dictates that the cell should be empty, and whether an overlooked historical or a possible future case might fit it. Lazarsfeld’s other modes of reduction are “pragmatic,” which collapses contiguous types, and “arbitrary numerical,” which, similar to Boolean algebra and QCA, collapses types into those sharing certain combinations that might be considered sufficient for the outcome. For example, we might code the habitability of a house with plumbing and no heat or refrigerator as the same as that of a house with heat and a refrigerator but no plumbing. Bailey, Typologies and Taxonomies, pp. 27-28. For our purposes, we find principles of reduction that focus on the suitability of specified types and extant cases for alternative case study research designs more useful.
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For this reason, Miriam Fendius Elman’s edited volume, Paths to Peace: Is Democracy the Answer? (Cambridge, Mass.: MIT Press, 1997), rightly includes case studies of mixed and nondemocratic dyads.
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A researcher can also examine a “typical” case (as identified by a statistical distribution or more crudely by the most populated type in a typology) to see how causal processes unfold in such a case. The most-likely or extreme case corresponds with Weber’s notion of an “ideal type” case, while the typical case corresponds with John McKinney’s notion of a “constructed type.” John McKinney, Constructive Typology and Social Theory (New York: Appleton-Century-Crofts, 1966). Both are examples of a “criterion” type, or a type against which other cases can be measured. Bailey, Typologies and Taxonomies, pp. 17-24.
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If for the sake of simplicity the types are delineated into nominal or ordinal approximations of interval variables, the variance that remains in the levels of the independent variables within the same type may account for differences in the outcomes among cases in the type. In this instance, the researcher must decide whether to redraw the partitions between the types, which complicates the theory, or explain the discrepancy in the narrative explanations of the cases and in a footnote to any tables presenting the typological theory.
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This treatment of “crucial” cases is somewhat different from that of Harry Eckstein, who devised the term. See Harry Eckstein, “Case Studies and Theory in Political Science,” in Fred Greenstein and Nelson Polsby, eds., Handbook of Political Science, Vol. 7 (Reading, Mass.: Addison-Wesley, 1975), pp. 118-120. Our formulation is more precise on whether a case is most- or least-likely for a particular theory, and whether alternative theories make complementary or contradictory predictions.
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Daniel Little, while more pessimistic than we are on the possibilities for typological theorizing, concurs that such theorizing can be strengthened by process-tracing. As an example, Little notes that Theda Skocpol’s work on social revolutions, in addition to using traditional comparative analysis based on Mill’s methods, uses established social theories in this manner. Little, “Causal Explanation in the Social Sciences,” p. 54.
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Alexander L. George and Richard Smoke, “Deterrence and Foreign Policy, “World Politics, Vol. 41, No. 2 (January 1989), pp. 170-182; and Robert Jervis, “Rational Deterrence: Theories and Evidence,” World Politics, Vol. 41, No. 2 (January 1989), pp. 183-207.
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We therefore disagree with the criticism that case study methods do not account for interaction effects. Stanley Lieberson makes this critique in “Small N’s and Big Conclusions,” in Ragin and Becker, eds., What is a Case? pp. 109-113. For a view that concurs with our emphasis