Mixed-methods research in nephrology

Mixed-methods research involves the mixing of at least 1 qualitative and 1 quantitative method in the same research project or set of related projects. Combined use of qualitative and quantitative research methods in nephrology has increased over the last 10 years. In this review, we aim to advance the understanding of mixed-methods research within the kidney community. Qualitative and quantitative techniques provide different but noncompeting representations of what exists in the world; findings from qualitative research do not generalize to a large population, whereas those from quantitative research may not apply to individuals within the diverse and heterogeneous larger population. Mixed-methods research combines these complementary representations, allowing the strengths of each method to be combined and the strengths of 1 method to address the limitations of the other. Mixed-methods approaches can be used to: (i) gain a more complete understanding of a research problem, (ii) explain initial results from one method with results from another, (iii) generate instruments, for example, survey tools and interventions, (iv) evaluate services, and (v) optimize clinical trial design and delivery. There are 3 core mixed-methods designs: explanatory sequential, exploratory sequential, and convergent parallel, which can be combined. We discuss each design in turn before discussing analysis and integration of findings from the different methods. We provide case studies that illustrate the application of these study designs to kidney research questions. We briefly discuss mixed-methods systematic reviews and evidence synthesis before finally highlighting guidance on how to appraise published mixed-methods research.