Information for researchers
The study design has three components:
Random sample of people in the three age groups in the Central Clydeside Conurbation.
Random sample of people in the three age groups from two localities in Glasgow City.
Smaller numbers of respondents from either the regional or locality samples who are invited to take part in more focused studies.
The samples were drawn from Strathclyde Region's Voluntary Population Survey (VPS), an enhanced electoral register which lists people of specified age and sex within households. Each of the cohorts was sampled using a two stage stratified random procedure based on postcodes and targeted individuals within postcodes, selected with a probability proportional to the total population. Because the VPS is a confidential list, representatives of Strathclyde Region first sought written permission from potential respondents (and parents in the case of 15 year olds) to pass their names on to the MRC. Interviewers then approached those who had so consented to ask them to participate in the study.