Transitioning to larger groups: using roles to promote an equitable physics lab experience

Many institutions face resource constraints that necessitate larger group sizes in introductory undergraduate physics labs. This transition from smaller to larger groups raises an important question: How can we ensure every student has meaningful engagement with all experimental aspects—including equipment setup, troubleshooting, prediction, analysis, leadership, and responsibility—leading to equitable learning outcomes? Our institution recently transitioned from two-student to primarily four-student lab groups, initially prompted by the COVID-19 pandemic's online instruction requirements and maintained after returning to in-person learning. To address participation inequities observed in two-student groups (where students often settled into fixed roles in each lab), we implemented a system of weekly-rotated, pre-defined roles: First Experimentalist, Second Experimentalist, Theorist, and Manager. We will share our experience transitioning to larger lab groups and provide implementation guidelines to help other institutions facilitate equitable student experiences in physics laboratory settings.