Mapping rigour in mixed methods research: a systematic review of methodological guidance

Introduction
Mixed methods research is increasingly applied in psychology, yet its rigour remains difficult to assess. Existing evaluative criteria often fail to address the methodological heterogeneity inherent to mixed designs. As mixed methods gain traction, synthesising guidance on rigour—especially in light of emerging openness practices—has become a methodological priority.

Goals and Methods
This project integrates existing guidance on how to promote rigour in psychological mixed methods research. We conduct a systematic review in PubMed, Web of Science, PsycINFO, as well as SocArXiv and PsyArXiv using Boolean operators, truncation, and controlled vocabulary. In addition, we screen all articles from three key mixed methods journals, instructions for authors in high-impact psychological journals that publish mixed methods, as well as all existing reporting guidelines for mixed methods. Finally, we review five cornerstone methodological handbooks.

Results
The review will produce a typology of rigour-enhancing strategies, with attention to openness-related practices such as transparency in integration, preregistration of mixed designs, and reflexivity in interpretation. Preliminary findings suggest fragmented yet overlapping guidance, with greater consensus in procedural than philosophical domains. The analysis also identifies areas where rigour in mixed methods remains underexplored.

Conclusions
This synthesis will contribute a consolidated overview of strategies for ensuring rigour in psychological mixed methods studies. By addressing both methodological diversity and the evolving landscape of openness, it offers a foundation for improved design, reporting, and evaluation. The output will inform the development of an accessible guidance tool to support researchers, educators, and reviewers navigating the complexities of mixed methods research.