8. Prior to the 1981 Census, number of births was only asked of women who were, or had been in a registered marriage. From the 1981 Census onwards, total number of babies has been asked of all women aged 15 years and over.
9. In the 1986 Census the question about number of children ever born also included a category for number of children deceased. This was excluded from the 1996 Census because consultation with user groups found that they were predominantly interested in the number of children born and demand for whether they were living or deceased was minimal.
10. The 1992 Family Survey collected data on children ever born, including their date of birth. The aim of collecting birth data from the survey was to produce data that would assist the formulation of population projections, birth-related needs in the community, and women's labour force participation. The 1992 Family Survey cross-classified number of children ever born, with date of birth data, to produce information about birth spacing.
11. It is possible to measure male paternity by asking a specific question but this would duplicate information which is more reliably collected of females. For certain types of analysis, information about the number of children men have had, may be useful. For example, the 1992 Family Survey collected information from men about the number of children outside the household because non- custodial parents and support networks beyond the household are an issue of social concern.
12. The censuses restrict the question to females 15 years of age and over because of the sensitive nature of the question for females less than 15 years. The Family Survey excludes women aged 60 and over, as well as 15-17 year-old women whose registered marital status is 'never married', and who are not living in a current de facto relationship.
13. The Births, Australia (cat. no. 3301.0) publication disseminates data on previous births which is compiled from information provided on birth registration forms to the Registry of Births, Deaths and Marriages in each State or Territory. Data obtained from these sources are not strictly comparable, as each jurisdiction asks the question in a slightly different way. For example, the Victorian Registry collects information about the previous births of the current relationship only, which may undercount total number of children ever born to the mother. However the Western Australia Registry collects information about previous births in the current relationship, and then asks an additional question about other children from previous relationships, providing a more accurate measure of children ever born to the mother.