This document summarizes a study on the challenges of implementing data-driven decision making (DDDM) in schools. It finds that while DDDM is a popular reform, moving data into usable knowledge to change instruction is difficult for teachers and principals. The study examines how teachers at one elementary school implemented DDDM along with other initiatives. It found that data was primarily used for language arts and math, not other subjects, and that requirements to implement multiple initiatives created tensions that decreased data use. How and when teachers used data depended on policies at multiple levels and the capacity of teachers and principals.