Are children intellectually impaired as a result of low birth weight and does relative impairment change as children grow older? Premature infants from a range of socioeconomic groups were studied in five rounds over 13 years to provide neurological, psychological, achievement, and sociological data on 582 children in three birth weight groups. A summary based on the final round makes these points: (1) Birth weight is related to reading and arithmetic achievement when social class and race are controlled, (2) Birth weight remains a significant correlate when an attempt is made to control for neurological status (estimated at age 40 weeks), (3) The correlation between indices of mental development and late adolescent intellectual behavior approaches zero, (4) Arithmetic is apparently more sensitive as an indicator of impairment due to birth weight than is reading, (5) None of the statistical interactions between race, social class, birth weight, and achievement were significant. (Tables make up one-half of the document.) (WY)