The 2007 reauthorization of Head Start requires Head Start programs to use child assessments and developmental screeners that are developmentally, linguistically, and culturally appropriate, as well as valid and reliable in the language in which they are used. This can be a challenge, since very few child assessment tools are developed or tested with linguistically and culturally diverse samples or with samples of children with disabilities (Pena & Halle, 2011; Spiker, Hebbeler, & Barton, 2011). Further, staff members in Head Start and other early childhood education programs rarely have the time, and may lack the technical training, to review and compare complex psychometric information on the quality of assessment and developmental screening tools. This compendium has been created to address this need and to promote the use of reliable and valid assessment data, wherever possible, in Head Start and other early childhood programs.