Teamwork assessment methods, such as peer evaluations, often fail to accurately capture the collaboration processes in team projects. While log data from digital collaboration tools (e.g., GitHub, Google Docs, Slack) provides objective evidence of contributions, effectively leveraging these data remains challenging. We conducted interviews (10 instructors, 16 students) and surveyed 51 students to identify their valued teamwork behaviors to guide log data usage, and investigate the perceived benefits and concerns. Students prioritized work-related behaviors such as equitable contribution and timeliness, whereas instructors additionally valued interaction behaviors like mutual support. Both groups highlighted significant limitations in existing log data, including omission of offline contributions, insufficient representation of work quality, mis-attributing contributions to “scribe” only, and risks of “gaming the data”. Many students reviewed logs on their own to monitor project progress and workload equity, but lacked structured guidance to meaningfully interpret the insights. Our findings underscore the need for student-centered teamwork assessment approaches that enable students to not only annotate and contextualize their own data, but also improve their teamwork by reflecting on a rubric of valued teamwork behaviors.