Linking data collected by early care and education (ECE) programs to data collected by other agencies provides a unique opportunity for early childhood leaders to understand the full experiences of the children and families they serve. ECE programs can benefit from linking their data because linked data can improve program quality, improve services for children, reduce the data collection burden on families and staff, and inform strategic planning. Linked data has many uses, including to help shape the delivery of the services, individualize the care provided to children, avoid duplication of services, and clarify the goals of the program itself. In this resource, data are considered "linked" when information from two or more separate data systems or databases are shared, connected, combined, or merged. These data systems or databases may be housed in the same program or in multiple programs or agencies. Linking data can occur in various ways ranging from simple, (e.g., sharing a spreadsheet) to more complex (e.g., merging two databases into a single file), to very complex (e.g., fully integrating data across multiple agencies). However, all linked data can provide useful information to support ECE program improvement. There are many practices that ECE programs can engage in to make data linking possible and ensure that their linking efforts are successful. This resource focuses on six of the best practices that ECE programs can institute to facilitate the process of data linking. (author abstract)