All eligible study members were contacted.
| Provided information | tbc |
| Cumulative total of deaths | tbc |
| Cumulative permanent refusals | tbc |
| Temporarily living abroad | tbc |
| Cumulative Emigrated | tbc |
| Failure to contact | tbc |
For cohort members who were at school, college or further or technical education the administrative authorities of those establishments were asked to complete postal questionnaires about courses attended. Cohort members who were at university were asked to complete a postal questionnaire about their courses, leisure activities, and health, and were asked also to complete the short Maudsley Personality Inventory.
Instructions are given at the head of each form.