Federal policy allows Head Start grant recipients to apply to the Office of Head Start to shift funding (i.e., convert enrollment slots) from Head Start services for preschool-age children to Early Head Start services for pregnant women, infants, and toddlers. Head Start grant recipients applying to convert enrollment slots are required to cite data in their applications demonstrating that planned changes will best meet the needs of Head Start– and Early Head Start–eligible children and families in the community and will support program quality and sustainability (Head Start Program Performance Standards, 45 CFR 1302.11). This brief describes the data sources and data points that Head Start grant recipients cited in applications to convert slots to center-based Early Head Start. (author abstract)