The scope of the study has broadened from a strictly medical focus at birth, to encompass physical and educational development at the age of five, and physical, educational and social development at the ages of 10 and 16. Subjects from Northern Ireland, who had been included in the birth survey, were dropped from the study in all subsequent sweeps, so further studies in the series cover Great Britain only.
In addition, there have been four sub-sample surveys carried out. The first two, carried out in 1972 and 1973, named the British Births Child Survey, followed up sub-samples of the original cohort at ages 22 months and 42 months. The third sub-sample survey was carried out in 1977 when non-respondents from the 5 year survey were traced and interviewed in an attempt to assess the effect of non-response. In 1991, when the cohort were aged 21 years, a 10% sample survey was carried out which focused on adult literacy and numeracy problems as well as the transition from school to work.
UKDA currently holds data under generic study number 33229 for the birth, 22-month, 42-month, five-year, 10-year, 16-year, 26-year and 1999-2000 follow-up surveys only. The 1999-2000 BCS70 follow-up survey was combined with the latest wave of the NCDS, and is held as a combined dataset under the UK Data Archive study number 4396. It is planned that the timing of future waves of the cohort studies will be integrated, in order to enhance their research potential, enabling comparisons to be made between cohorts born at different times, or between different age groups at the same point in time.