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This data quality statement applies to
Age (AGEP), Age in Ten Year Groups (AGE10P), Age in Five Year Groups (AGE5P), and Imputation Flag for Age (IFAGEP)


This variable describes a person's age. As in 2006, respondents had the option to report either Date of Birth (DOB) or Age last birthday (question 4). Where both sets of information were provided, DOB was used to derive an age in years, except in circumstances where errors in DOB were identified.

Where age was not stated or could not be derived, it was imputed using other information on the form and an age distribution of the population. The proportion of persons that had their age imputed in the 2011 Census was 4.2% compared to 5.0% in 2006. The majority of imputed ages are attributed to persons in occupied dwellings on Census Night that did not return a form. A smaller proportion were due to persons who returned a partially completed form without reporting age. There were also a small number of cases where respondents reported an age outside the acceptable range or where there were inconsistencies between age and relationship data.

The variable Imputation Flag for Age (IFAGEP) indicates if a person's age was imputed in the Census. There are two categories:

1 Age not imputed
2 Age imputed

Age (AGEP) is subject to two main types of error: respondent and processing error.

Respondent error

Respondents occasionally make errors in reporting their age or date of birth, such as reporting their last birthday or the date they filled out their Census Form rather than their date of birth, parents filling in the form on their children's behalf and inadvertently reporting their own age or date of birth for their children, character transposition errors, or other typographical errors (e.g. sticky key repetition). The latter two are particularly relevant to eCensus.

Processing error

Data captured from written responses carries a small risk of character recognition error, mainly caused by poor handwriting or respondents writing outside the question box. The vast majority of individual characters written on paper forms met preset recognition confidence levels and were accepted without further examination. Characters that failed given recognition confidence levels, or responses where there was a discrepancy of more than three years between age last birthday and date of birth, were sent to clerical staff for further determination based on visual inspection of an image of the response.

Other checks on age (such as unlikely combinations of age and other variables) were made at various stages during processing, to ensure an acceptable level of quality was maintained.

Age data is also available as Age in 5 Year and Age in 10 Year groups.

For the official ABS estimate of demographic data on the Australian population, users should refer to Australian Demographic Statistics (cat. no. 3101.0).

More information on AGEP is available in the 2011 Census Dictionary (cat. no. 2901.0)

Question 4 as it appeared on the 2011 Census Household Form

Image of question 4 from the 2011 Census
A text only version of this question is also available

Back to Person classification




Household / Dwelling

2011 Census Dictionary