Summary.The National Survey of Health and Development is a longitudinal study of 5,000 boys and girls. This paper describes the sample of 3,465 with full information on two measures of educational success which summarise their progress and achievement at school: (a) a combination of 15 year test scores; and (b) a scale of attainment at 18, based on examinations, leaving age and type of employment. A series of discriminant analyses of the 15 year test scores against the attainment scale shows mathematics and reading to be the best predictors of school progress both for each social class considered separately and for the population as a whole.