Case Studies and Theory Development in the Social Sciences - Alexander L. George [184]
42
David Collier and Steven Levitsky, “Democracy with Adjectives: Conceptual Innovation in Comparative Research,” World Politics, Vol. 49, No. 3 (April 1997), pp. 430-451. Collier and Levitsky also note the use of “diminished subtypes,” or cases that lack a few attributes of the overall concept, such as “limited suffrage democracies” (pp. 437-442).
43
David Collier, “Comparative Historical Analysis: Where Do We Stand?” American Political Science Association: Comparative Politics Newsletter, No. 10 (Winter 1999), pp. 1-6.
44
Charles Ragin, The Comparative Method: Moving Beyond Qualitative and Quantitative Strategies (Berkeley: University of California Press, 1987).
45
Bear F. Braumoeller, “Causal Complexity and the Study of Politics,” (unpublished manuscript, Harvard University, Cambridge, Mass., 2002).
46
Christopher H. Achen and Duncan Snidal, “Rational Deterrence Theory and Comparative Case Studies,” World Politics, Vol. 4l, No. 2 (January 1989), p. 160; and Barbara Geddes, “How the Cases You Choose Affect the Answers You Get: Selection Bias in Comparative Politics,” Political Analysis, Vol. 2 (1990), pp. 131-150.
47
David Collier and James Mahoney, “Insights and Pitfalls: Selection Bias in Qualitative Work,” World Politics, Vol. 49, No. 1 (October 1996) p. 59.
48
Ibid., p. 60; and King, Keohane, and Verba, Designing Social Inquiry, pp. 128-132.
49
Collier and Mahoney, “Insights and Pitfalls,” p. 60.
50
Douglas Dion, “Evidence and Inference in the Comparative Case Study,” in Gary Goertz and Harvey Starr, eds., Necessary Conditions: Theory, Methodology, and Applications (Lanham, Md.: Rowman and Littlefield, 2003), pp. 95-112; and Collier, “Translating Quantitative Methods for Qualitative Researchers,” p. 464.
51
Case study researchers in many instances should make comparisons between the subset of cases or types studied and the larger population, where there is more variance on the dependent variable (Collier and Mahoney, “Insights and Pitfalls,” p. 63). Sometimes, such comparisons can be made to existing case studies in the literature, or the researcher might include “mini-case” studies, or less in-depth studies, of a wide number of cases in addition to full studies of the cases of greatest interest. To say would like to have the functional equivalent of a controlled experiment, with controlled variation in independent variables and resulting variation in dependent variables, but the requisite cases for such research designs seldom exist. that such comparisons are often useful for many research goals, however, is very different from arguing that they are always necessary for all research goals.
52
The standard protection against this bias in statistical studies is random selection, but as King, Keohane, and Verba note (Designing Social Inquiry, pp. 124-127), in studies of a small number of cases, random selection can be more likely to result in bias than intentional selection.
53
David Laitin, “Disciplining Political Science,” American Political Science Review, Vol. 89, No. 2 (June 1995), p. 456.
54
Collier and Mahoney, “Insights and Pitfalls,” pp. 71-72.
55
The reader should note that any necessary condition can be inverted and stated as a sufficient condition, and vice versa. To say that “A is necessary for B” (for a specified population or set of scope conditions) is the same as saying “the absence of A is sufficient for the absence of B” (for the specified population or scope conditions). Thus from a methodological point of view any discussion of testing a necessary condition can be restated in terms of testing a sufficient condition, and vice versa.
56
See Dion, “Evidence and Inference,” pp. 95-112.
57
One further variation on methods for assessing necessity and sufficiency is Charles Ragin’s suggestion for using “fuzzy set” techniques to examine theories that make probabilistic assertions about conditions that are “almost always” or “usually” necessary or sufficient. Such relationships might be more commonly observed than deterministic relationships of necessity