David Kuehn & Ingo Rohlfing, "Causal Explanation and Multi-Method Research in the Social Sciences", February 2010

After a long and often fiercely fought debate over the respective values of quantitative and qualitative methods in the social sciences, multi-method research (MMR) is emerging as a new methodological paradigm. The debate on MMR meets with the ongoing discussion about standards of good causal inference and explanation. It is now widely acknowledged in the philosophy of science and social sciences that one should strive for causal explanations that include propositions of both causal effects and causal processes. Our paper provides a systematic discussion of the potential of MMR to assess and produce robust causal explanations, which is an issue that has received surprising little attention so far. We argue that the salient dimension to be addressed in light of the plea for causal explanations and MMR concerns the distinction between deterministic and probabilistic causality. In the first part of the paper, we detail the implications of determinism and probabilism for the formulation of causal explanations and cross-case and within-case propositions in particular. Based on this framework, we evaluate the potential of MMR to develop and test causal explanations in the second part. We conclude from this discussion that the causal inferences generated through MMR are considerably less certain than the current state of the debate about MMR suggests.