The study examines the relationship between interim data-use practices at the school and classroom levels and student achievement. The study draws on teacher and principal survey data with more than 1,500 teachers and 150 school principals and student achievement data from over 60,000 students across four urban districts collected during the 2009-10 school year. The study tests a theory of action that links key dimensions of data use and hypothesizes that supporting conditions in states, school districts, and schools can facilitate the effective use of data to respond to students’ instructional needs and improve learning. Study results reveal some statistically significant relationships between a summary measure of interim data use and student achievement, but results were not consistent across elementary and middle school levels nor across reading and mathematics. Relative to more specific components of the theory of action, teachers’ attention to interim data in the classroom and principals’ attention to data in the school, as well as principals’ perceptions of support for data use were related to higher achievement at some grades and subjects. Results suggest that “the more that teachers and principals reported reviewing and analyzing student data and using this information to make instructional decisions, the higher was their students’ achievement” at least in some grades and subjects. For principals, “the more they reported having support in the form of data infrastructure, adequate time for review and discussion of data, professional development, and the appropriate human resources, the higher their students’ achievement." Again, these results varied by grade and content area.