Summary.A national sample of over 11,000 children, from the National Child Development Study, was the basis for a study of laterality prevalences, consistencies and changes from 7 to 11 years of age. Consistency and changes in handedness were related to levels of ability and attainment at age 11. Approximately 86 per cent of children were consistent in their hand preference from 7 to 11; and most children who changed were mixed‐handed at 7. There were clear differences between boys and girls in the incidence of non‐right‐handedness. At age 11 the group of consistent left‐handers had lower ability and attainment scores than average, although the very small group of left‐handers who changed from being right‐handed at 7 were well ab