As Research Software Engineers (RSEs) become more integrated into academic institutions and scientific grant proposals, there's a growing need to understand their impact, but empirical data on RSEs' technical and scientific contributions remains limited. To address this gap, Carnegie Mellon's James Herbsleb (who studies code contributions and hackathons) and University of Washington's Anissa Tanweer (an expert on data science practices) propose a comprehensive study combining ethnographic research on four university-based RSE teams and their scientific partners, as well as large-scale analysis of networks and code contributions in open-source scientific software projects with RSE involvement Schmidt Sciences will co-fund this initiative, and study sites will include representation from their "Virtual Institute for Scientific Software" program. The research aims to identify challenges, best practices, and impact measurements for RSE teams, with findings targeted toward university administrators and funders who are considering investments in RSE positions—delivering timely insights as this professional role continues to evolve.