The questionnaire has been continuously revised and developed but a basic part has been retained that allows us to follow trends over time.
The questionnaire survey conducted in Phase 6 has an estimated response percentage of about 50, which is satisfactory for such a comprehensive survey. Altogether, 9820 completed questionnaires were received from the different installations.
See link to Questionnaire survey 2005 - frequency tables in the link box. A summary of the replies in the questionnaire survey has also been considered and commented on in the summary and main reports.