A PACE Policy Brief by Susanna Loeb, Tara Beteille and Maria Perez of Stanford University explains why California must accelerate its efforts to create an effective data system for collecting and using vital school information. Building an Information System to Support Continuous Improvement in California Public Schools highlights the elements of an effective data system, with a particular focus on issues related to data collection. It reveals that despite efforts to improve California’s education data system, the state continues to lag behind other states in data collection and management, in policy evaluation and data use and in funding for local school districts to support the collection and maintenance of reliable education data. The authors show that valuable lessons can be learned from the high quality data systems that have been created in other states, and in organizations in both the public and private sectors. They argue that data, if used wisely, can help to transform California’s education system.