The NICHD Study of Early Child Care (SECC) is a comprehensive longitudinal study initiated by The National Institute of Child Health and Human Development (NICHD) in 1989 to answer the many questions about the relationship between child care experiences and characteristics and children's developmental outcomes. Researchers are following the children, measuring their development at frequent intervals from birth through middle childhood.

Phase I of the study was conducted from 1991-1994, following the children from birth to age 3 years.

Phase II of the study was conducted between 1995-2000 to follow the children continuing to participate from age 3 through their third year in school.

Phase III of the study is currently being conducted to follow children to the year 2005 through their sixth year in school.