The Comparative Method

I The Comparative Method .I I r J, I David Collier Comparison is a fm•d•ny:ntaJ tool of analysis. It shaipeas out power of description, and plays a c:eatral role in coacept-formatioa by bringing into focus suggestive similarities aud contrasts amoog cases. Comparison is routinely used in testing hypotheses, and it can contribute to the inductive discovery of new hypotheses and to theory-building. The forms of comparison employed in the discipline of political science vary widely and include those contained in statistical analysis, experimmtal research, and historical studies. At the same time, the label comparative method bas a standard meaning within the discipline and in the social mote broadly: it refers to the methodological issues that arise in the systematic analysis of a small number of cases, or a small N. 1 This chapter examines alternative perspectives on the comparative method that have emerged over roughly the past two decades. Although the primary focus is on discussions located in the fields of comparative politics and international studies, the application of the comparative method is by no means restricted to fields. The decision to analyze only a few cases is strongly influenced by the types of political phenomena under study aud how they are conceptuafu.ed. Topics for which it is productive to examine relatively few cases include revolutions, particular types of national political regimes (e.g., post-conummist regimes), oc particular forms of UJban political systems. This focus oa a small number of cases is adopted because tbeze exist relatively under consideration that few instances of the exhibit the attnl>utes of interest to the analyst. Alternatively, some analysts believe that political phenomena in general are best understood through the careful examination of a small numbec of cases. In the field of comparative and international studies, the practice of focusing on few cases has achieved greater legilimllcy in recent years in conjunction with the rise of the school of comparative historical analysis, • in which small numbers of countries are studied ovei- loog periods. This close scrutiny of each country limits the number of national cases a scholar can consider. 2 Choosing to study few cases routinely poses the problem of having more rival explanations to assess than cases to observe, or the quandary of many variables, small N (Lijphart 1971, 686). Elementary statistic.a teaches us that u the number of explanatory factors approaches the number of casea, the capacity to adjudicate among the explanations through statistical comparison rapidly diminisl>es. Thia problem has stimu- lated much discussion of bow most productively to analyze a small N. The late 1960s and early 1970s saw a boom in writing on comparative method (e.g., Merritt and Rokbn 1966; Kallebecg 1966; Verba 1967; Smelser 1968; Lasswell 1968; Pneworslci and Teune 1970; Sartori 1970; Merritt 1970; Etzioni and Dubow 1970; Lijpbart 1971; Vallier 1971; Zelditcb 1971; Armer and Grim.maw 1973). This literature established a set of nonns and practices for small-N research. proposed alternative strategies for conducting such analyses, and created a base line of understanding that has played an important role in the ongoing practice of small-N studies. This chapter assesses the issues of comparative method that have been debated in the intervening years and considers their implications for ongoing research. The point of departure is Arend Lijpbart's (1971) article •Comparative Politics and Comparative Method.• Among the studies published in that period, Lijpbart's piece stands out for its imaginative synthesis of basic issues of comparison and of the relation between comparative method and other branches of metbodology. 3 It therefore provides a helpful framework foe examining, and building upon, new developments in the field. A central theme that emerges in the discussion below is that refinements in methods of small-N analysis have substantially broadened the range of techniques available to comparative researchers. The most fruitful approach is eclectic, one in which scholars are willing and able to draw upon these diverse techniques.