This article describes the potential for using K–12 education data to support school improvement efforts and the effective and efficient use of education resources. It examines the availability and transparency of education data in California as part of the Getting Down to Facts effort to improve education decision making in that state. The study addresses three broad questions related to the state's education data system: (1) What is the current condition of California's education data system? (2) What is being done to strengthen it? and (3) What are the obstacles and challenges to improving the system so that it can be an effective tool for helping policy makers and education leaders understand how schools are performing and how resources can most effectively be allocated?