With this manuscript, we make a methodological contribution to mixed methods research by exploring the systematic development of quantitative measurement instruments from qualitatively reconstructed typologies, using the example of teachers' epistemological beliefs in teaching humanities subjects. The qualitative, verbal database for these considerations consists of group discussions that were analyzed using the documentary method in order to create a typology.
We address the systematic and methodologically sensitive translation of qualitative typologies into quantitative measurement instruments. Through in-depth methodological reflection, we explore how the methodological principles of the documentary method are used to inform the development of survey items. We highlight the challenges of reconciling the implicit, practice-oriented nature of qualitative-reconstructive insights with the explicit, operationalized demands of quantitative frameworks, and repeatedly relate these considerations to a qualitative typology of teachers' epistemological beliefs in teaching humanities subjects. The proposed approach allows for iterative integration, offering a pathway to bridge these methodological divides. With this research, we contribute to advancing the integration of mixed methods by demonstrating how qualitatively derived typologies can inform robust quantitative analyses.