In recent years, there has been a surge in work on what has come to be known as “qualitative methods.” The trend is essentially reactive, developing as a response to the outpouring of work on quantitative and formal methods and the assertions by scholars in those areas that case studies and historical work are impressionistic, unscientific, and noncumulative. To counter such claims, some of the field's most distinguished qualitative scholars (e.g., Stephan Van Evera, Guide to Methods for Students of Political Science, 1997; James Mahoney and Dietrich Rueschemeyer, eds., Historical Analysis in the Social Sciences, 2003; and Marc Trachtenberg, The Craft of International History, 2006) have spent much time and ink to show that researchers who eschew regressions or game theory can be just as methodologically aware and sophisticated as those who embrace them. Alexander George and Andrew Bennett's Case Studies and Theory Development in the Social Sciences is an impressive and welcome addition to this literature.
Alexander George has helped to explicate and develop the case study method for decades, and with his former student Andrew Bennett he has produced a book that is not only clear and comprehensive but also bold and frank. The authors' first contribution is to offer a systematic guide to the nuts and bolts of case study–based research. There are chapters on designing, executing, and analyzing the results of case studies; on distinguishing structured, focused comparison, controlled comparison, and within-case analysis; on case studies and the philosophy of social science; and on two particular types of work that George and Bennett advocate, process tracing and the congruence method. Taken together, these chapters tell students and fellow practitioners all they need to know (and more) about how to go about such research.
However, the book also offers a spirited defense of why scholars should do it—a subject that other recent books on qualitative methods have neglected. Two of the authors' arguments are worth special mention, those relating to causality and to the generation of new insights, hypotheses, and theories.
George and Bennett argue that case studies offer the best, and perhaps only, way to explore causality. Only by carefully studying the unfolding and dynamics of particular cases, they claim, can scholars figure out precisely what mechanisms and variables caused a particular political outcome to occur. Case study analysis can “check for spuriousness,” “document … alternative causal paths to the same outcome and alternative outcomes for the same causal factor,” and remains “the only observational means of moving beyond covariation alone as a source of causal inference” (pp. 223–24). “Even when rational choice theory or other formal models predict outcomes with a fairly high degree of accuracy,” the authors note, “they do not constitute acceptable causal explanations unless they demonstrate … that their posited or implied causal mechanisms were in fact operative in the predicted cases” (p. 208). By reminding us that the central challenge of political science is understanding why political outcomes occur, they perform a great service to a discipline that in recent years has grown unhealthily obsessed with hypothesis testing (or the “logic of confirmation”) alone.
George and Bennett are also keen to assert the contributions that case studies can make to the generation of new thinking. Here they take aim at the claim made by Gary King, Robert Keohane, and Sidney Verba (1994) in Designing Social Inquiry that “there is no such thing as a logical method of having new ideas…. Discovery contains ‘an irrational element,’ or a ‘creative intuition’” (p. 12). George and Bennett agree that there is no surefire way to produce new ideas, but argue that case study work is uniquely well positioned to uncover “variables that were otherwise left out in the initial model” and generate new hypotheses “through the study of deviant or outlier cases and in the course of field work” (p. 20). Statistical methods, in contrast, “can identify deviant cases that may lead to new hypotheses, but in and of themselves … lack any clear means of actually identifying new hypotheses” (p. 21).
In sum, Case Studies and Theory Development in the Social Sciences aims to show not only that case study–based work can be as sophisticated and methodologically aware as quantitative and formal work, but also that it offers distinctive advantages in addressing causality and producing fresh thinking. With its fairly accessible style and helpful tips for teaching, this should make it a must-read for all political scientists interested in methodology.
