Quality Statement
This information by concept is primarily about household composition. There is a suite of household variables that are closely related, and further information is available in the Appendix for the following related variables:
- Age of oldest person in household
- Age of youngest child in household
- Age of youngest dependent child in household
- Household composition by child dependency status
- Number of dependent children in household
- Number of usual residents aged 15 and over in household
- Number of usual residents aged under 15 in household
- Number of usual residents in household.
A household is either one person who usually resides alone, or two or more people who usually reside together and share facilities (such as for eating, cooking, or a living area; and bathroom and toilet) in a private dwelling.
People who were absent on census night but who usually live in the dwelling and are members of that household are also included in households. Generally, these will be people who were elsewhere in New Zealand or away from New Zealand for less than 12 months.
Household composition classifies households according to the relationships between usually resident people. The classification is based on how many and what type(s) of family nuclei were present in a household, and whether there were related or unrelated people present.
Household composition: High quality
Data quality processes section below has more detail on the rating.
Priority level 2
A priority level is assigned to all census concepts: priority 1, 2, or 3 (with 1 being highest and 3 being the lowest priority).
Household composition is a priority 2 concept. Priority 2 concepts cover key subject populations that are important for policy development, evaluation, or monitoring. These concepts are given second priority in terms of quality, time, and resources across all phases of a census.
The census priority level for household composition remains the same as 2018.
The 2023 Census: Final content report has more information on priority ratings for census concepts.
Household composition: Households in occupied private dwellings
‘Subject population’ means the people, families, households, or dwellings that the variable applies to.
Household composition is classified into the following categories:
Household Composition Standard Classification 2008 V1.0.0 - Level 1 of 3
| Code | Category |
|---|---|
| 1 | One-family household (with or without other people) |
| 2 | Two-family household (with or without other people) |
| 3 | Three-or-more family household (with or without other people) |
| 4 | Other multi-person household |
| 5 | One-person household |
| 6 | Household composition unidentifiable |
Household composition uses a 3-level hierarchical classification with level 1 presented in the table above. Follow the link above the table to examine the classification and to find more detail.
The 2023 Census classification for household composition is consistent with that used in 2018 Census.
Standards and classifications has more information on what classifications are, how they are reviewed, where they are stored, and how to provide feedback on them.
Household composition is derived from information about the people who usually live in the household: usual residence (question 5 on the individual paper form), living arrangements (question 17 on the individual paper form) and relationship to reference person (questions 18 and 21 on the dwelling paper form).
For more information on question format see households, families, extended families, see Count of families and households – 2023 Census: Information by concept
Stats NZ Store House has samples for both the individual and dwelling paper forms.
Data-use outside Stats NZ:
- by central government agencies, local authorities, private organisations, and researchers in the formulation of social policy, for planning and monitoring programmes, and for research purposes.
Data-use by Stats NZ:
- household data is used to produce household estimates and projections.
- as a comparison for admin household variables (which then guides changes to improve admin household variables).
Data sources for individuals included in households and families are from either census responses or admin enumerated records in occupied private dwellings.
The data source for households can be from census responses only, admin enumerations only, or a mixture of both census responses and admin enumerations. Methodology for using admin data to count people in the 2023 Census has more information about admin enumeration.
Blank households are private dwellings containing no census respondents or admin enumerations, but where a household of usual residents would be expected.
| Data sources used to derive family and household data – households in occupied private dwellings | |
|---|---|
| Source of household counts | Percent |
| Household from census forms | 92.3 |
| Admin enumerated household | 3.1 |
| Household from both census forms and admin enumeration | 1.2 |
| Blank household | 3.5 |
| Total | 100.0 |
| Note: Due to rounding, individual figures may not always sum to the stated total(s). | |
For admin enumerated records and where information from census forms was missing, relationship information from historical census data and admin data was used. Sources of admin relationship information include:
- Department of Internal Affairs births, deaths, marriages, and civil unions
- Ministry of Business, Innovation and Employment visa applications
- Ministry of Social Development partnership and child data
- Working for Families tax return details.
For the purposes of household and family coding for the 2023 Census, admin relationships were restricted to partners, parents, children, siblings, grandparents and grandchildren.
Household composition does not have a non-response category as it is a derived variable.
There is no direct question on the census forms that asks about household composition. Instead, household composition is derived from the household matrix (grid of relationships between people in the household). The final matrix is a mixture of relationships from relationship to reference person, relationships derived from these, admin relationships, imputed relationships, and relationships assigned by Manual Intervention. Where the quality of the household matrix is poor (for example, the matrix is incomplete), household matrices are coded as residual and household composition is classified as ‘household composition unidentifiable’.
Household composition is also classified as ‘household composition unidentifiable’ for blank households.
Percentage of ‘Household composition unidentifiable’ for households in occupied dwellings:
- 2023: 4.1 percent
- 2018: 3.9 percent
- 2013: 2.6 percent.
‘Families and Households in the 2023 Census: Data sources, methodology and data quality’ will have more information on missingness in household and family data. A link to the paper will be available in late 2024.
Overall quality rating for household composition: High
Data has been evaluated to assess whether it meets quality standards and is suitable for use.
Three quality metrics contributed to the overall quality rating:
- data sources and coverage
- consistency and coherence
- accuracy of response.
The lowest rated metric determines the overall quality rating.
Data quality assurance in the 2023 Census provides more information on the quality rating scale.
Data sources and coverage: High quality
The quality of all the data sources that contribute to the output for the variable have been assessed. To calculate a data sources and coverage quality score for a variable, each data source is rated and multiplied by the proportion it contributes to the total output.
The rating for a valid census response is defined as 1.00. Ratings for other sources are the best estimates available of their quality relative to a census response. Each source that contributes to the output for that variable is then multiplied by the proportion it contributes to the total output. The total score then determines the metric rating according to the following range:
- 98–100 = very high
- 95–<98 = high
- 90–<95 = moderate
- 75–<90 = poor
- <75 = very poor.
The main data source for all household variables is the household matrix; therefore, the data sources for the matrices are used to calculate the metric 1 rating for all the household variables. The sources of data for the matrix of a household are the sources of the units that make up the household, that is, whether the household is made up of units from census responses only, admin enumerations only, or a mixture of both census responses and admin enumerations.
The final category is blank household, these have no individual usual residents (and therefore no unit sources).
The total score of 0.96 gives a metric 1 quality rating for the derived household variables of high.
| Data sources and coverage rating calculation for households in occupied private dwellings, 2023 Census | |||
|---|---|---|---|
| Source | Rating | Percent | Score contribution |
| Household from census forms | 1.00 | 92.27 | 0.92 |
| Admin enumerated household | 0.76 | 3.09 | 0.02 |
| Household from both census forms and admin enumeration | 1.00 | 1.17 | 0.01 |
| Blank household | 0.00 | 3.47 | 0.00 |
| Total | 100.00 | 0.96 | |
| Note: Due to rounding, individual figures may not sum to the stated totals(s) or score contributions | |||
Consistency and coherence: High quality
Household composition is consistent with expectations across nearly all consistency checks, with some minor variation from expectations or benchmarks which makes sense due to real-world change, incorporation of other sources of data, or a change in how the variable has been collected.
This includes an increase in multi-family households and large households in the 2023 Census. This is attributed to real-world change (more people living in multi-generational and larger households), higher response rates for Māori and Pacific Peoples, and higher quality household matrices.
Accuracy of responses: High quality
Accuracy of responses were assessed through the quality of the methods for completing the relationships in the household matrices and also from the analysis of people missing from households.
Household composition data has only minor data quality issues. The accuracy of coding for the household matrix is high.
There were significant changes introduced in the 2023 Census that impacted the quality of household matrices and therefore the quality of household variables. These were:
- improvements in the methodology for using admin relationships to construct families and households when census relationships were missing
- more extensive checks for errors, and higher quality manual corrections for households that had errors due to a dedicated and larger family coding manual intervention team
- higher quality repatriation of people to the dwelling they usually live in.
'Families and Households in the 2023 Census: Data sources, methodology and data quality’ will have more information on the data quality of household and family data. A link to the paper will be available in late 2024.
It is recommended that household composition data can be used in a comparable manner to the 2018 and 2013 Censuses.
When using this data, users should be aware that:
- Counts of families, extended families and households are unable to receive a rating higher than the count of dwellings rating of ‘high’, because identifying units depends on the quality of dwelling data and the accuracy of occupancy status for private dwellings. The Dwelling count - 2023 Census: Information by concept has more information on the rating of dwelling units.
- Not all people counted in the census usually resident population are part of the derivation of households and families, eg people who were admin enumerated at a meshblock rather than a dwelling level and people living in non-private dwellings. In addition, there are dwellings that were not occupied at the time of the census or not counted in the census. This means there will be families, extended families and households that are not counted in census outputs.
- Care should be taken when looking at the time series as there were changes to the collection strategy, processing system, and household and family coding methodology between the 2013 and 2018 Censuses, and further improvements made to these for the 2023 Census. These improvements mean household and family data is of a higher quality in the 2023 Census compared to previous censuses.
- The quality of relationships within households in the 2023 Census is higher than in previous censuses, including those for more complex households and households containing at least one member of the Māori or Pacific Peoples ethnic groups.
‘Families and Households in the 2023 Census: Data sources, methodology and data quality’ will have more information on changes to the methodology and data quality of household and family data. A link to the paper will be available in late 2024.
To assess how this concept aligns with the variables from the previous census, use the links below:
- Families and households: household composition - 2018 Information by variable
- Household composition - 2013 Information by variable
Information by variables for other household variables were not published in 2018 or 2013.
Contact our Information centre for further information about using this concept.
All household variables carry the same data sources and coverage and accuracy of responses quality ratings - both ratings are high for all outputs.
Included in the table below are the quality ratings for related household variables. Follow links for further definitions and classification information.
| Quality ratings for related variables | ||||
|---|---|---|---|---|
| Variable | Overall quality rating | Metric 1 | Metric 2 | Metric 3 |
| Age of oldest person in household | High | High | High | High |
| Age of youngest child in household | High | High | High | High |
| Age of youngest dependent child in household | High | High | High | High |
| Household composition by child dependency status | High | High | High | High |
| Number of dependent children in household | High | High | High | High |
| Number of usual residents in household | High | High | High | High |
| Number of usual residents aged under 15 in household | High | High | High | High |
| Number of usual residents aged 15 and over in household | High | High | High | High |
Household variables are consistent with expectations and consistency checks, with some minor variation from projections that makes sense due to real-world change, incorporation of other sources of data, or a change in how the data has been collected or processed.
The count of larger households (six or more usual residents) has increased for the 2023 Census, especially for Māori and Pacific Peoples households, which can be explained by improved collection and processing as well as real-world change, especially due to housing costs.
Patterns for age of oldest person in household vary by regional council and district health board as reflected by real-world patterns for highly urban areas and as per demographic patterns in these areas by ethnicity and Māori descent, which can shift the area to younger distributions.
It is recommended that all household variables can be used in a comparable way to the 2018 and 2013 Censuses.
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