Engineering education researchers are increasingly integrating qualitative and quantitative research methods to study learning and retention in engineering. While quantitative methods can provide generalisable results, qualitative methods generate rich, descriptive understanding of the investigated phenomenon. On the other hand, a mixed methods approach provides benefits of the two approaches by incorporating them in a single study. However, engineering faculty often faces difficulty in integrating qualitative and quantitative methods and designs in their education research. This article discusses mixed methods in the context of an actual ongoing engineering education research project investigating student resistance to active learning. We describe the research design in phases that show the integration of quantitative and qualitative results, and how these data sources can help influence the direction of the research and triangulate findings. Our mixed method research experience highlights the importance of thinking iteratively between qualitative and quantitative data sources during the instrument development process.