Overall Research Project Description The goal of this research project is to examine the types of knowledge that graduate student instructors (GSIs) use when teaching student-centered and active learning classes. This project will follow mathematics graduate students serving as GSIs for small sections of Precalculus as they engage in professional development for and teaching of five active-learning lab units. These units are designed to supplement lecture class material by taking a deep dive into foundational Precalculus concepts such as quantitative and covariational reasoning, exponential and logarithmic function behavior, and modeling of real-world scenarios. The professional development provided to these GSIs is specific to the teaching of these labs with a focus on examining and analyzing student work, facilitating classroom discussions about mathematics, and creating classrooms where students feel comfortable and safe to share their thinking with their peers. I am looking for research assistants who are interested in learning more about education research processes such as qualitative data collection and management, mathematics learning and teaching, and/or professional development for practicing teachers.