The Educational Testing Service (ETS) is beginning a comprehensive longitudinal study of the cognitive, personal, and social development of disadvantaged children from age 3 to grade 3. ETS hopes to identify the antecedents of favorable intellectual and social development and to suggest what kinds of educational programs might help to bridge the gap between the disadvantaged and the more affluent. The study will involve 9 groups of children in 23 elementary school districts in New Jersey, Alabama, Missouri, and Oregon. Some of the principal features of the study design are that: (1) the groups will be "natural" rather than "contrived," i.e. parents will decide about their children's participation in Head Start or kindergarten in the ordinary way; (2) the subjects will be English-speaking Negro and white children; (3) where possible, ETS selected districts that were mixed by race and socioeconomic status; and (4) cross-sectional comparison groups were included to provide baseline data. Data will be collected from measures of the family, measures of the child's physical, perceptual, cognitive, and personal-social development, and measures of the classroom, teacher, school, and community. Interviews, observation techniques, medical examinations, questionnaires, and tests will be used to collect data. Cooperation from parents, schools and Head Start program personnel is actively being sought by ETS. (MH)