My lab studies teaching and learning in physics and other science, technology, engineering, and math (STEM) courses. We study research questions such as how students acquire skills or content knowledge, how different course environments affect students’ motivation or their persistence in physics (or other STEM fields), or how they develop an understanding of the nature of science and scientific measurement. We spend considerable time worrying about how we know what outcomes are being achieved and what mechanisms are responsible for those outcomes. We use both qualitative (e.g. observations, interviews, and focus groups) and quantitative methods (e.g. test scores, instances of pre-defined actions or activities) to explore the many possible variables that affect student learning and their experiences in physics and STEM courses.