Page 148 - PhD GT

Chapter 7
The main study: methods, procedures and sample characteristics
7.0 Introduction
In order to investigate the nature of change in dependence, a follow-up study of individuals seeking help for problems of alcohol and heroin dependence and misuse was carried out. The site chosen for recruitment to the study was the Leeds Addiction Unit, first described in Chapter 4; further relevant descriptive detail is presented below.
In this chapter, the sample selection and the methods of data collection are described. This is followed by a description of the samples captured at the three data collection points: intake (t1), three months (t2) and twelve months (t3), and a description of the ways in which those individuals who were traced and who participated in follow-up differed from those who were not traced and who did not participate in follow-up. The purpose of presenting the time 1 (t1) data for those not followed up at each data collection point and comparing these with the data for those who were followed up, is to attempt to establish the possible bias in the findings relating to the sample that was followed up. Demographic characteristics, measures of substance use and dependence, general health and social satisfaction for each of the sub-samples are given. The whole sample seen at intake (n=230) is described as Sample 6, those seen at intake and three months are Sample 6a, those seen at intake and twelve months are 6b and those seen at all three data collection points are Sample 6c.
7.1 Sampling
The aim of sampling was to obtain a representative sample of a typical help seeking population of primary heroin and alcohol users, in similar proportions to those reflected in normal referral patterns at the Leeds Addiction Unit (Leeds Addiction Unit 1997) and with similar gender and age distributions. Demographic and substance use data from other, similar agencies were examined to establish the extent to which help-seekers at the study agency were representative of help-seekers at similar agencies locally and nationally. The site for sample selection was the agency
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