This article examines the use of interim assessments in elementary schools in the School District of Philadelphia. The article reports on the qualitative component of a multimethod study about the use of interim assessments in Philadelphia. The study used an organizational learning framework to explore how schools can best develop the capacity to utilize the potential benefits of interim assessments. The qualitative analysis draws on data from intensive fieldwork in 10 elementary schools and interviews with district staff and others who worked with the schools, as well as further in-depth case study analysis of 5 schools. This article examines how school leaders and grade groups made sense of data provided through interim assessments and how they were able to use these data to rethink instructional practice. We found substantial evidence that interim assessments have the potential to contribute to instructional coherence and instructional improvement if they are embedded in a robust feedback system. Such feedback systems were not the norm in the schools in our study, and their development requires skill, knowledge, and concerted attention on the part of school leaders.