Abstract
The progress is described of the longitudinal cohort study based on all children born in England, Scotland and Wales in one week of April 1970. The children and their mothers have been surveyed at birth, at five, and recently, at ten. Analyses of the data presented include the finding of improved intellectual outcome in children who had been immunized against pertussis, compared with poor intellectual outcome in children who had had hospital admissions for the disease itself. Preliminary data collected at 10 show that routine hearing and vision testing during the child's school life fell short of recommended standards. The major aim of the 10-year-old contact, however, is to establish details of the national prevalence and pathogenesis of disability. The identification of disability uses a life skills questionnaire, medical history and examination.