Notes compiled for collaborators who use ALSWH data
ALSWH sampling scheme for the 1921-26, 1946-51 and 1973-78 cohorts
1973-78, 1946-51 and 1921-26 cohorts
The study sample was selected by Medicare Australia (previously known as the Health Insurance Commission) from three zones - urban, rural and remote defined according to RRMA(ref) where urban includes Capital City and Other Metropolitan Centres; rural, Large Rural Centres, Small Rural Centres and Other Rural Areas; and remote, Remote Centres and Other Remote Areas. The age groups sampled from the Medicare database in April 1996 were 18-22 years, 45-49 years and 70-74 years. By the time the invitations to participate were mailed later in 1996, some women at the upper limit of the age groups had had their birthday and were a year older. Hence some women recruited were 23, 50 and 75 years old and so the cohort age ranges in the study are: 18-23; 45-50 and 70-75 years (although there are relatively fewer women in the oldest year of each cohort). The cohorts are now referred to by their years of birth but some ALSWH material may refer to them as 'Young', 'Mid-aged' and 'Older' and data sets use 'y', 'm', and 'o' (further information below). Sampling from the population was random within each age group, except that women from rural and remote areas were selected in twice the proportions of the Australian population living in these areas. Women from capital cities and other metropolitan areas made up the balance of the samples. There were also a small number of women invited to participate whose age was outside the cohort birth years (by a year or two), possibly due to errors in date of birth in the Medicare database. However the survey data for these women have been retained. We recommend that when using the data, these women are either excluded or their age set to the nearest valid age.
Please note that some variables in Surveys 1 and 2 of the 1989-95 cohort were renamed for consistency in April 2016.
Renaming of Variables in the Surveys 1 and 2 for the 1989-95 cohort
Recruitment for the 1989-95 cohort was different from the other cohorts. A variety of recruitment strategies were used (see the Report I, section 3.) A brief summary is given here.
For inclusion in the 1989-95 cohort, respondents needed to:
- meet the eligibility criteria of being female, aged 18 to 23 and having a Medicare number;
- answer at least some survey questions;
- meet the requirements for data linkage.
A total of 17,567 women met the above inclusion criteria. To establish a pilot study group for the cohort, the first 498 young women that met the above criteria were removed from the main cohort. As a result the pilot study group included all women recruited in October 2012 who were verified by the Department of Human Services. Of the remaining sample, 17,069 participants were verified by the Department of Human Services.