Age has been collected in all Australian Censuses. Age data, combined with sex data, are essential for the production of accurate population estimates based on the Census count.
The 2011 Census form gives respondents the option of writing in their age and/or their date of birth. Age is calculated from date of birth when provided, otherwise stated age is used. Only age in years data are output. If neither age nor date of birth is provided, age is imputed using other information on the form and using an age distribution of the population. The variable Imputation Flag for Age (IFAGEP) is used to indicate if a person's age has been imputed for the Census.
For 2011, AGEP classifies each person's age into single year categories, from 0 to 115 years. For infants aged less than one year, 0 years of age is recorded.
Age is used during processing as a cross check with other variables; for example, the age of the respondent determines whether particular questions asked in the Census are applicable.
If age is under 15 years, then the following person variables are not applicable:
Community Development Employment Projects Participation (CDEP);
Voluntary Work for an Organisation or Group (VOLWP).
The following age constraints apply:
if age is under five years, then the following variables are not applicable: Place of Usual Residence Five Years Ago (PUR5P) and Usual Address Five Years Ago Indicator (UAI5P);
if age is under one year, then in addition to the above, the following variables are also not applicable: Place of Usual Residence One Year Ago (PUR1P) and Usual Address One Year Ago Indicator (UAI1P);
age and Year of Arrival in Australia (YARP) must be logically consistent; and
the household or family reference person must be aged 15 years or over.