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Sample

1996 – Original three cohorts

More than 40,000 women responded to the baseline surveys for the main cohorts in 1996. Because of uncertainties about the accuracy of the Medicare database (which was used as the sampling frame for the stratified random samples), response rates cannot be exactly specified. It is estimated that 37-40%, 53-56% and 41%-42% of the 1921-26 cohort, the 1946-51 cohort and the 1973-78 cohort, respectively, responded to the initial invitation to participate.

Some participants completed Survey 1 in 1996 and did not provide any contact details (508 women from the 1921-26 cohort, 383 women from the 1946-52 cohort and 532 women from the 1973-78 cohort). Also, a very small number of women have alerted the study that they were not eligible by their birth date and they have been removed. Hence the numbers of women actually enrolled in the Australian Longitudinal Study on Women’s Health (ALSWH) were 12,432 women in the 1921-26 cohort 14,247, 13,714 women in the 1946-51 cohort and women in the 1973-78 cohort (Lee, C., Dobson, A. J., Brown, W. J., Bryson, L., Byles, J., Warner-Smith, P., & Young, A. F. (2005). Cohort Profile: the Australian Longitudinal Study on Women’s Health. International Journal of Epidemiology, 34(5), 987-991). https://doi.org/10.1093/ije/dyi098

Socio-demographic characteristics

Main current employment status1973-78 cohortABS 18-23 years1946-51 cohortABS 45-50 years1921-28 cohortABS 70-75 years
Number of respondents14,762759,68014,072734,15512,804377,152
Employed full-time (%)31.332.41.36.136N/AN/A
Employed part-time (%)19.226.430.128.5N/AN/A
Worked (without pay) /
employed (other) (%)
1.91.37.02.0N/AN/A
Unemployed (%)6.410.51.94.0N/AN/A
Total not in labour force (%)39.426.321.627.0N/AN/A
Not stated (%)1.82.73.32.5N/AN/A
Highest qualification completed1973-78 cohortABS 18-23 years1946-51 cohortABS 45-50 years1921-28 cohortABS 70-75 years
Number of respondents14,762759,68014,072734,15512,804377,152
Australia (%)88.677.869.062.668.566.4
Other English speaking (%)3.54.113.911.612.411.0
Other Europe (%)1.31.68.711.09.712.7
Asia (%)3.610.64.38.21.83.3
Other/not stated (%)3.06.04.26.57.66.5
Aboriginal/Torres Strait Islander1973-78 cohortABS 18-23 years1946-51 cohortABS 45-50 years1921-28 cohortABS 70-75 years
Number of respondents14,762759,68014,072734,15512,804377,152
Non indigenous (%)97.994.998.196.791.693.7
Aboriginal or TSI (%)1.62.70.81.10.30.4
Not stated (%)0.52.51.12.18.15.9
Country of birth1973-78 cohortABS 18-23 years1946-51 cohortABS 45-50 years1921-28 cohortABS 70-75 years
Number of respondents14,762759,68014,072734,15512,804377,152
No post school qualification (%)69.869.363.161.879.870.4
Trade/Apprenticeship (%)2.47.93.57.03.72.7
Certificate/Diploma (%)15.16.015.98.77.33.3
University Degree (%)12.17.716.311.64.02.4
Other (not stated,
inadequately described) (%)
0.69.11.210.85.221.2
Present marital status1973-78 cohortABS 18-23 years1946-51 cohortABS 45-50 years1921-28 cohortABS 70-75 years
Number of respondents14,762759,68014,072734,15512,804377,152
Married (%)8.29.075.173.054.748.9
Separated/divorced (%)0.01.113.218.76.36.8
Widowed (%)0.00.22.12.735.239.9
Never married (%)79.089.83.95.63.24.4
De Facto (not collected by ABS) (%)12.05.70.6
Present housing situation1973-78 cohortABS 18-23 years1946-51 cohortABS 45-50 years1921-28 cohortABS 70-75 years
Number of respondents14,762759,68014,072734,15512,804377,152
House (%)74.379.484.789.276.779.3
Flat/apartment/unit (%)20.014.07.16.519.412.9
Other (%)5.76.68.24.33.97.9

Table 1: Socio-demographic characteristics for the young, mid-age and older respondents and for women of the same age in the general population (ABS). The above tables and information are taken from: Brown, W. J., Dobson, A. J., Bryson, L., & Byles, J. E. (1999). The Australian Longitudinal Study on Women’s Health: on the progress of the main cohort studies. Journal of Women’s Health & Gender-Based Medicine, 8(5), 681-688. https://doi.org/10.1089/jwh.1.1999.8.681

Comparison of original cohorts with Australian Censuses

Demographic characteristics (Indigenous status, country of birth, marital status, lone person household, education, and employment) of respondents at each of the surveys have been compared with those of women of the same age in the Australian population, using data from the Australian Census conducted closest to the survey.

  • Powers, J (2004) Comparison of the Australian Longitudinal Study on Women’s Health cohorts with women of the same age in the 2001 Census. Technical Report. Newcastle: ALSWH. In: Technical Report February 2004.
  • Australian Longitudinal Study on Women’s Health (2009) Comparison of the ALSWH cohorts with women of the same ages in the 2006 Census and the 2004/2005 National Health Survey. In: Technical Report No. 32. 111-142.
  • Australian Longitudinal Study on Women’s Health (2013) Comparison of the ALSWH cohorts with women of the same ages in the 2011 Census. In: Technical Report No. 36. 107-135.

As was found previously, there was some over-representation of Australian-born women and of women with tertiary education. In addition, ALSWH participants were more likely to be married, be employed and work longer hours than women of the same age in the general population. Some of these differences will be due to differences in the questions asked and the sampling frame i.e. to be selected for ALSWH women must have a Medicare card.

2013 – ‘New Young Cohort’, born 1989-95

In 2012 and 2013, 17010 18-23 year old women were enrolled in the 1989-95 cohort. Women were mainly recruited using the internet and social media platforms. Consistent with the other cohorts, women were required to have a Medicare card. Women completed the online survey and provided consent to linkage of survey data with administrative databases such as Medicare.

Due to this different method of recruiting it was not possible to provide a response rate. Therefore it was necessary to compare the representativeness of the sample with women of the same age in the closest Australian Census (see Table 6). The 1989-95 cohort were broadly representative in terms of area of residence, State and Territory distribution, marital status and age distribution. Women with tertiary education were over-represented. Mishra GD, Hockey R, Powers J, et al (2014) Recruitment via the Internet and social networking sites: the 1989-1995 cohort of the Australian Longitudinal Study on Women’s Health. J Med Internet Res. 16(12):e279. https://doi.org/10.2196/jmir.3788

Comparison of sociodemographic characteristics of the 1989-95 cohort of women aged 18 to 23 in 2013 with women of the same age range in the 2011 Australian Census

Age1989-95 cohort 20132011 Census
Number of respondents17 069847 042
18 (%)15.216.0
19 (%)17.516.2
20 (%)17.216.8
21 (%)16.517.1
22 (%)16.917.0
23 (%)16.917.0
State/territory1989-95 cohort 20132011 Census
Number of respondents17 069847 042
New South Wales (%)27.831.0
Victoria (%)24.025.4
Queensland (%)22.320.6
Western Australia (%)11.010.6
South Australia (%)7.67.3
Australian Capital Territory (%)3.32.0
Tasmania (%)2.92.1
Northern Territory (%)0.81.0
Area of residence1989-95 cohort 20132011 Census

Number of respondents17 069847 042
Major city (%)75.374.5
Inner regional (%)16.616.0
Outer regional (%)6.77.2
Remote (%)0.81.1
Very remote (%)0.30.9
Migratory/no usual address (%)N/A0.3
Missing (%)0.3
Highest qualification1989-95 cohort 20132011 Census
Number of respondents17 069847 042
Less than year 12 (%)7.414.9
Year 12 or equivalent (%)43.046.1
Certificate/diploma (%)25.921.7
University degree (%)22.59.4
Missing/not stated/inadequately described (%)1.27.8
Aboriginal or Torres Strait Islander*1989-95 cohort 20132011 Census
Number of respondents14 909*847,042
No (%)97.391.9
Yes (%)2.73.4
Missing (%)0.04.7
*n=14 909 as this question was only asked in a later version of the survey
Marital status*1989-95 cohort 20132011 Census

Number of respondents14,909*847 042
Never married (%)95.594.5
Married (%)3.04.9
Separated/divorced/widowed (%)0.40.6
Missing (%)1.2
*n=14,909 as this question was only asked in a later version of the survey