Using longitudinal data from the Early Head Start Family and Child Experiences Survey 2009 (Baby FACES 2009), this study examines the psychometric properties of infant and toddler measures of language and cognitive development and social-emotional competence collected from multiple sources, including parent and Early Head Start staff reports and direct assessments from trained assessors. We examined the validity and reliability of parent/staff ratings and observational measures derived from adult/child play-based interactions using independently administered standardized measures from direct assessments as the criteria or comparison measures. Participants included 846 children and families with low incomes enrolled in Early Head Start in spring 2009 who were followed from ages 1 to 3, drawn from a nationally representative sample of programs. The results suggest adequate internal consistency reliability for most of the measures. (author abstract)