While adolescent foundational skills interventions can be critical levers for reading improvement, district leaders, teachers, and researchers must make complex decisions about how to evaluate their effectiveness in context. In this discussion article, we explore three issues and tensions we experienced during a 2-year research-practice partnership overhauling Tier II high school reading intervention practices in a district serving largely African American students. First, we discuss assessment and the challenges of using data and reading theory to simultaneously address system-level and student-level needs. Second, we share our process for choosing a curriculum and evaluating its effectiveness. Finally, we weigh how students' African American English may have been related to program implementation and foundational skills development. We share our takeaways to help practitioners and researchers seeking systematic foundational skills improvement across a district, especially districts like ours.