Participants in the Child Development Project (CDP) were originally recruited from public schools within three cities (Nashville and Knoxville, TN and Bloomington, IN) during kindergarten pre-registration in 1987 and 1988. The majority of the sample was enrolled by randomly approaching parents at pre-registration and inviting them to participate in a longitudinal study of child development, with ~75% agreement rate. Because a small percentage of children in the targeted schools did not pre-register (15%), a similar proportion of the CDP sample were recruited on the first day of school or through letter or telephone to maintain representativeness of the school population. The original CDP sample consisted of 585 children (52% male; 81% European American, 17% African American, and 2% other ethnic origin). The sample was generally representative of the three communities in terms of demographics and socioeconomic status. Data collection began the summer before the participants entered kindergarten (at approximately 5 years of age), and follow-ups have been conducted annually and remain on-going. Approximately 485 subjects continue to participate regularly in CDP assessments. Participants who continue involvement in the CDP are
