This brief from the Center for Urban Education Leadership at the University of Illinois Chicago describes a key contributor to the persistent disparities found in student learning outcomes in Chicago Public Schools and shows how this knowledge can help identify specific sources of inequities, particularly for schools with predominantly Black student enrollments. The authors present a data-based approach to identifying and examining a prominent type of high-need school—the high-churn school—through publicly available administrative data. Both the concept of “churn” and the initial data analysis presented in the brief can inform efforts to strengthen the processes of continuous improvement at the system level. This brief can be of considerable use to principal preparation programs and school districts seeking to develop principal leadership to improve schools that seem resistant to improvement over time.