ABSTRACT
Any study which looks at the some aspects of the lives of a large number of people must make some assessment of other characteristics of that population. This is in order to gauge how homogeneous the population is in terms ofimportant social variables such as age, education, social class, etc. While we make no such grandiose claims as Westwood, in this chapter we present details of the social background of the cohort at fIrst interview, then discuss data reliability and attrition across all sites.
