This chapter describes three members of a college of education, all working in different roles to prepare teachers. In response to various external and internal pressures to improve and demonstrate program quality (such as accreditation and a Gates-funded reform agenda), the three chose to collaborate on the idea of a "culture of evidence." They decided to systematically inquire into what they believed was an important data set: student teacher performance assessment scores. The authors knew that every teacher education program collected such scores, and they wondered what a close analysis of their own program's might reveal. Initially the authors defined "performance assessment" very broadly, meaning all the aspects of student teaching observation and coaching and performance and feedback that might be studied. Ultimately, they found that digging deeply into "just" the scores determined by university supervisors observing in classrooms illuminated many dimensions of teacher education from the programmatic to the personal. The score data, aggregated across semesters, was required to gain national accreditation of the program; at the same time, an individual student teacher interpreted scores as a reflection on her competence and likelihood of success as a teacher. The authors discovered that what they learned about student teacher performance assessment could be useful as a basis for reflection by "the program." Which is to say, they could be used by the program leaders and the faculty at all ranks together, participating in a culture of evidence. Even as the authors found that they did not have the agency to demand significant attention to what they had learned, they nevertheless gained important insights into how collaborative leadership might support a culture of evidence. [For the complete volume, "Cross-Disciplinary, Cross-Institutional Collaboration in Teacher Education: Cases of Learning and Leading. Palgrave Studies on Leadership and Learning in Teacher Education," see ED616372.]