State policymakers are increasingly focused on closing the achievement gap and preparing all students to succeed in school and in life. However, college and career readiness begins long before students enter high school or even a classroom. Differences in children's abilities appear as early as the first year of life, and research has shown that targeted interventions during the early childhood years can narrow the "school readiness gap." Accurate, timely and quality early care and education (ECE) data are necessary to inform policy decisions; guide the daily work of ECE professionals; and support coordination among ECE programs, the K-12 system, and other systems that serve young children and their families. To support state policymakers' efforts to build and use coordinated ECE data systems, seven national organizations established the Early Childhood Data Collaborative (ECDC). After identifying the critical policy questions confronting state policymakers, the ECDC identified 10 Fundamentals of coordinated state ECE data systems. The 10 ECE Fundamentals will increase the capacity of state policymakers and other stakeholders to answer critical questions about policy and practice, but that is only the beginning. To fully realize the potential of coordinated state ECE data systems, state policymakers need to establish policies, practices and structures that ensure appropriate access and help stakeholders use data effectively to guide decisionmaking. Early Childhood Data Collaborative Stakeholder Outreach is appended. (Contains 5 notes.)