Reflections on Leveraging Large-Scale Epidemiological Cohort Data to Enrich Qualitative Interview Sampling

Due to differing research traditions and philosophical positions, qualitative and epidemiological research are rarely integrated. Therefore, here, we reflect on how we integrated epidemiological methods into a purposive sampling approach to obtain a highly diverse study sample for our in-depth qualitative study ( N = 37) from the Dutch Lifelines Cohort Study ( N = 152,728). This study contributes to mixed methods research, as we first reflect on benefits and challenges related to interdisciplinarity among researchers, also in relation to open science practices. Second, we discuss the integration of quantitative epidemiological elements into a purposive sampling strategy and how this resulted in an information-rich and varied study sample. Last, we provide hands-on recommendations and lessons learned on integrating epidemiological and qualitative techniques within an interdisciplinary setting.