This brief describes the psychometric properties of the screening and assessment tools used to measure the language and overall development of children in the Early Head Start Family and Child Experiences Survey (Baby FACES). It includes analyses of the different types of validity and reliability of the Ages & Stages Questionnaires-Third Edition, the MacArthur-Bates Communicative Development Inventories, the Early Communication Indicator-Adapted. It also includes brief descriptions of the Preschool Language Scale-Fourth Edition, the Peabody Picture Vocabulary Test-Fourth Edition, and the Bayley Behavioral Rating Scale, and information on how these scales are used in the Baby FACES study. Finally, the brief outlines recommendations for Early Head Start programs to consider when selecting assessment measures, based on the experience of Baby FACES researchers.