Empirical Methods in Constitutional Law

In the current methodological debate in comparative constitutional law, there is little reflection on the use of qualitative methodology and its methodological implications. The proposed paper advocates process tracing is a qualitative methodology that is well suited for use in comparative constitutional law and discusses the methodological implications. The argument consists of three steps. First, the paper argues that quantitative approaches have certain shortcomings so that they need to complemented by qualitative studies. Second, the paper argues that process tracing is the perfect complement to quantitative approaches, remedying some of the shortcomings of the latter. In the final part, the paper will give some guidelines on how process tracing might be used in comparative constitutional law.

Petersen and Chatziathanasiou discuss recent empirical trends in constitutional law scholarship in a recent article and suggest that this body of research may be all “smoke and mirrors.“ They focus on two well-documented issues with empirical research using observational data—omitted variable bias and measurement error—arguing that these problems are severe enough to call into question the entire body of research. But while pointing out real obstacles, they fail to account for how these issues have been addressed by existing literature. We make four points in reply. First, we explain that the scholarship is continuously developing new approaches to address the problems raised. Second, we describe efforts to address these problems. Third, we argue that the methodological pluralism that the article advocates is already underway. Finally, we suggest that evaluating an entire literature is best done using a “systematic review,“ to ensure a fair characterization of the field evaluated.

For a long time, (comparative) constitutional legal scholars have tried to evaluate the consequences of constitutional design by drawing on and comparing select country cases. Such a qualitative empirical research approach, however, has its limitations. While it might be suitable to generate theories of how constitutions work, it is difficult to assess whether these explanations are valid when applied to a larger set of constitutions (i.e., whether findings from a single or few countries can be generalized) and whether one theory potentially outperforms other theories in explaining differences across countries and time. Thanks to the ever-increasing availability of sophisticated statistics software, powerful personal computers, and well-trained researchers, quantitative analyses of constitutions have surged in recent decades. In my contribution, I will focus on the opportunities, the challenges, but also the potential pitfalls of relying on quantitative methods to study constitutions.

This paper aims to speak to and advance the growing interest in empirical methods of conducting constitutional research. It begins by making the case for the focus group method as a means of obtaining information on, and a better understanding of, the constitutional culture in a given system. It also argues that this information is relevant to and may inform an understanding of how constitutional law is understood, articulated and applied within that system. Drawing on experience in conducting fieldwork that uses this method, the paper also includes an analysis of the limitations of this method and the challenges that can arise in applying it in the constitutional field.