Results from this two-year study of seven kindergarten curricula in 1973-74 support the hypothesis that structured programs produce greater cognitive gains for disadvantaged children. The study also suggests that a structured program may be more beneficial for high socioeconomic children. The six curricula described and evaluated are: Lippincott's Beginning Program, Alpha Time, Getting a Head Start, Follow Through Model, Regular Kindergarten Program (Fort Worth Independent School District), and Bilingual Model. The Lippincott's Beginning to Read, Write, and Listen Program (a highly structured language-based program) was found to be most effective for low socioeconomic status (SES), high SES, and Anglo and black children. Program effects were similar for middle SES children in the four curricula examined. The effects of half-day vs full-day sessions were not supportive of full-day programs for middle SES children either year. High SES students were not in full-day programs the first year of this study; however, the second year of this study full-day programs were found to be more advantageous to high SES children in the Lippincott curricula and the Fort Worth Independent School District continuum. The first year evaluation supported full-day programs for low SES children. Only full-day programs were provided for low SES children during the second year of this study. (Author/DEP)