The NICHD Study of SECCYD is a comprehensive longitudinal study initiated by the NICHD to answer questions about the relationships between child care experiences, child care characteristics, and children’s developmental outcomes. The major goal of the NICHD Study is to examine how differences in child care experiences relate to children’s social, emotional, intellectual, and language development, and to their physical growth and health. Funding for the SECCYD ended in 2009. Data collection on the characteristics of child care arrangements took place from 1991 to 1995, after which time the study participants were in kindergarten.