This report is intended to help states refine their capacity to use existing administrative data from early childhood (EC) programs to improve services for young children and families. Linking data collected across early childhood programs can help program leaders and policymakers better understand the needs of the children and families these programs serve as well as support continuous program improvement, innovation, and research. Integrated early childhood data can help to answer important questions related to program access, participation, quality, and their association with child outcomes. These answers can, in turn, inform how federal and state funds support young children's early learning, health, and development across a range of programs and services; impact resource allocation decisions; allow for examination of patterns in service use; identify areas for quality improvement and innovation; and improve the coordination of service delivery across systems at both the state and local levels. The first section of this report includes a vision for integrated EC data and explains how states can use integrated data to inform decisions. The second section covers key considerations when integrating and linking EC data based on the best practices from the field and lessons learned from eight states profiled that are actively engaged in developing integrated EC data systems. The report concludes with more detailed information about the eight profiled states. Because states and localities face challenges when attempting to integrate EC data, the U.S. Department of Education (ED) and the U.S. Department of Health and Human Services (HHS) have funded a variety of research projects and technical assistance (TA) centers to assist states in these efforts. Many of the resources that have been developed through these initiatives are highlighted in this report and listed in Appendix A. Appendix A also includes information on recent federal investments and opportunities to further the development of integrated data systems, federally-funded toolkits, and other useful resources. (author abstract)