'Age' is the length of time a person has been alive, measured in complete, elapsed years. It is measured as the difference between date of birth and 7 March 2006. Census information is available either by single year of age or by age group.
Relationship to questionnaire
Data on age is derived from question 4 on the individual form (PDF 395kb).
The subject population is the people, families, households or dwellings to whom the variable applies.
The subject population for this variable is the census night population, as this question applies to all people in New Zealand on census night. However, data on age can also be (and often is) output for the census usually resident population.
There is no non-response category for age, as a response is imputed if the question was not answered. This includes situations in which an entire individual form for a person within a household was not answered, and situations in which an entire household did not respond.
In 2006, age was imputed for 4.0 percent of the usually resident population.
In 2001, age was imputed for 3.7 percent of the usually resident population.
Quality Management Strategy priority level
Age is a foremost variable.
The Census Quality Management Strategy assigns a priority level to all census variables.
Foremost variables are core census variables that have the highest priority in terms of quality, time and resources across all phases of the 2006 Census.
All data must meet minimum quality standards in order to make it suitable for use.
Comparability with 1996 and 2001 Census data
There are no issues affecting the comparability of this data with 1996 and 2001 Census data.
There are no significant issues that users should be aware of.
Other things to be aware of
- All census data was subject to considerable checks (including edits) during processing and evaluation, to ensure that it meets quality standards and is suitable for use. These checks were applied to data supplied both on paper and on Internet forms. In addition to these quality checks, the Internet form had built-in editing functionality that directed respondents to the appropriate questions and ensured that their responses were valid. As a result of this, data from Internet forms may be of higher overall quality than data from paper forms. The significance of this will depend on the particular type of analysis being done.
- There were differences between how the forms were completed on the Internet and on paper for this variable:
- On the Internet, the date of birth question had to be answered and be a valid date in order for the respondent to submit the form (ie 1 to 31 for the day, 1 to 12 for the month, and 1886 to 2006 for the year). If the date entered on the Internet form was impossible (eg 31 February or 1685 for the year), a message popped up to alert the respondent and they had to change their response. Non-response to this question and responses outside the valid range were possible when forms were completed on paper.