Qualitative comparative analysis (QCA) is a new analytic technique that uses Boolean algebra to implement principles of comparison used by scholars engaged in the qualitative study of macrosocial phenomena (Ragin 1987). Typically, qualitatively oriented scholars examine only a few cases at a time, but their analyses are both intensive – addressing many aspects of cases – and integrative – examining how the different parts of a case fit together, both contextually and historically. By formalizing the logic of qualitative analysis, QCA makes it possible to bring the logic and empirical intensity of qualitative approaches to studies that embrace more than a handful of cases – research situations that normally call for the use of variable-oriented, quantitative methods. While quantitative methods are powerful data reducers, they embody strong assumptions about social phenomena that are often at odds with the interests of investigators. QCA avoids these troublesome assumptions. This chapter develops the contrast between qualitative (or caseoriented) research and quantitative (or variable-oriented) research as a way to introduce QCA and then presents a brief overview of the technique.

CASE-ORIENTED AND VARIABLEORIENTED RESEARCH STRATEGIES

In the study of macrosocial phenomena there are two basic research strategies, case-oriented and variable-oriented. While many different types of strategies have been described (e.g., Przeworski and Teune 1970; Bonnell 1980; Skocpol and Sommers 1980; Tilly 1984; Kohn 1989; and Janoski 1991), the continuum represented by the distinction between case-oriented and variable-oriented work forms the primary axis of variation among strategies.