Using a combined census model for the 2023 Census helps Stats NZ produce the highest quality data possible to show us how New Zealanders are living in Aotearoa New Zealand.
What is the combined model?
We combined data collected through census responses with alternative data sources. We only used alternative data sources when we didn't have a census form response, and when it was appropriate to do so.
We used administrative (admin) data to add records to the 2023 Census file. We also used admin data, data from previous censuses, and statistical imputation, to fill gaps in census variables.
Admin data is data that is collected by government agencies or other organisations while conducting their normal business. Examples of admin data are birth, death, and taxation records. We only consider using admin data where we have not already captured the information through census form responses. For the 2023 Census, admin data was sourced through the Integrated Data Infrastructure (IDI).
For the 2018 Census we introduced a combined census model to address data quality issues from low response in the census collection. The 2023 Census is different, in that we intentionally designed this census to use a combined census model.
We have been engaging proactively with our Treaty partners, stakeholders, and communities to maintain and develop their trust and confidence in the 2023 Census, including the safe use of admin data in a combined census model. More information is provided in:
Privacy impact assessment for the use of admin data in the 2023 Census
Detailed methodology
The combined census model for the 2023 Census is informed by several methodologies. The following papers describe the combined model implemented for the 2023 Census:
- Methodology for using admin data to count people in the 2023 Census describes the methodology for adding admin records (referred to as admin enumerations) to the 2023 Census file when an individual has not provided a response.
- Editing, data sources, and imputation in the 2023 Census summarises the approach to filling in gaps in census attributes when valid information has not been provided on 2023 Census forms.
- Linking 2023 Census responses to the Integrated Data Infrastructure reports how Stats NZ has linked responses from the 2023 Census to admin data records in the IDI, including changes to linking processes since the 2018 Census.
- Predicting usual residence address from admin data in the 2023 Census describes the implementation of a model to predict usual residence address from admin data sources available within the IDI.
- Data sources and imputation for Māori descent in the 2023 Census outlines the data sources and methods used to determine values for the 'Māori descent - output' variables in the 2023 Census, including the use of alternative data sources to mitigate missing census responses.
- Methodologies for filling gaps in gender and sex at birth concepts for the 2023 Census provides information on the methods used to fill gaps in the 'gender' and 'sex at birth' variables in the 2023 Census.
Earlier papers
The following papers were released in 2022 and detail the planned approach for the combined model in the 2023 Census. These are largely superseded by the papers listed above.
- Admin enumeration: Planned approach for the 2023 Census
- Editing, data sourcing, and imputation: Planned approach for the 2023 Census
- Family and household methodology: Planned approach for the 2023 Census
Contact us
If you have any questions about the combined census model or the 2023 Census in general, you can contact us:
[email protected]
0508 525 525.
