Title: Modeling when and how physics PhD students search for a research group: the role of interests and prior research experiences in timely group integration

Abstract: Studying the factors that influence the quality of physics PhD students' doctoral experiences, especially those that motivate them to stay or leave their programs, is critical for providing them with more holistic and equitable support. Prior literature on doctoral attrition has found that students with clear research interests who establish an advisor-advisee relationship early in their graduate careers are most likely to persist. However, these trends have not been investigated in the context of physics, and the underlying reasons for why these characteristics are associated with leaving remain unstudied. Using semi-structured interviews with 40 first and second year physics PhD students, we construct a model describing the characteristic pathways that physics PhD students take while evaluating interest congruence of prospective research groups. We show how access to undergraduate research and other formative experiences helped some students narrow their interests and look for research groups before arriving to graduate school. In turn, these students reported fewer difficulties finding a group than students whose search for an advisor took place during the first year of their PhD. Lastly, we identify two characteristic types of students at a higher risk of leaving their programs: students who enter graduate school with broad interests and struggle to find a group, and students who join a research group early based on research interest alone and subsequently encounter issues with a negative mentoring relationship. This work serves as a major step toward creating a comprehensive model of how PhD students find a research group, and opens the door for future work to investigate how factors such as group culture and working environment impact the search process.