The purpose of this research is to understand how people learn to do scientific research while participating in research groups and communities of research groups. A community of practice is a "group of people who share a concern or a passion for something they do and learn how to do it better as they interact regularly". A community of science practice (COSP) is a group of people associated with a science discipline(s) who understand and share specialized language, norms, and practices for participation and knowledge generation in the discipline(s). Identity formation as part of a COSP involves learning to legitimately participate in the specialized practices and discourses of the discipline. Such learning is conceptualized as a trajectory of apprenticeship where novices first learn through legitimate forms of peripheral participation, taking on more responsibility and ownership over time as they move towards full participation in the community. COSP research has described full participation as generating new knowledge through research. Structured research experiences are important forms of apprenticeship in a COSP. Although research experiences can have powerful effects on peoples' persistence in science education and research, more research is needed to understand the learning trajectories across different forms of legitimate participation in a COSP, from peripheral to full. This research focuses specifically on how people negotiate and author their science identities through legitimate forms of participation in a COSP.