Applying Formal Bayesian Analysis to Qualitative Case Research: An Empirical Example, Implications, and Caveats

Abstract

To illustrate how Bayesian logic underpins qualitative research, we provide an application to Fairfield’s (2015) work on tax policy change in Latin America. Fairfield (2013) elaborated a methodological appendix that we believe is the first published account that explicitly applies process-tracing tests to elucidate causal inferences in the author’s case narratives. In the following exercise, which is also the first of its kind, we revise that appendix by replacing the language of process-tracing tests with direct applications of Bayes’ theorem. While we advocate a Bayesian approach to inference over process-tracing tests, we stress the fundamental difficulty of assigning quantitative probabilities in the complex world of social science.