When Multi-Method Research Subverts Methodological Pluralism-or, Why We Still Need Single-Method Research

While acknowledging the many forms and contributions of multi-method research (MMR), we examine the costs of treating it as best practice on the grounds that it reduces method-specific weaknesses and increases external validity for findings. Focusing on MMR that combines some type of qualitative analysis with statistical or formal approaches, we demonstrate that error-reduction and cross-validation are not feasible where methods are not sufficiently similar in their basic ontologies and their conceptions of causality. In such cases, MMR may still yield important benefits-such as uncovering related insights or improving the coding of variables-but these can be readily obtained through collaboration among scholars specializing in single-method research (SMR). Such scholars often set the standards for the application of particular methods and produce distinctive insights that can elude researchers concerned about competently deploying different methods and producing coherent findings. Thus, the unchecked proliferation of multi-method skill sets risks forefeiting the benefits of SMR and marginalizing idiographically-oriented qualitative research that fits less well with formal or quantitative approaches. This would effectively subvert the pluralism that once gave impetus to MMR unless disciplinary expectations and professional rewards are predicated on a more balanced and nuanced understanding of what various forms of SMR and MMR bring to the table.