Quality Statement
Māori descent concept defines if a person is of Māori descent, not of Māori descent, or does not know if they are of Māori descent. A person is of Māori descent if they are descended from Māori.
Māori descent is based on a genealogical or biological concept. For the purposes of the Māori descent classification, having Cook Island Māori ancestry is not classified as being of Māori descent.
Very high quality
Data quality processes section below has more detail on the rating.
Priority level 1
A priority level is assigned to all census concepts: priority 1, 2, or 3 (with 1 being highest and 3 being the lowest priority).
Māori descent is a priority 1 concept. Priority 1 concepts are core census concepts that have the highest priority in terms of quality, time, and resources across all phases of a census.
The census priority level for Māori descent remains the same as 2018.
The 2023 Census: Final content report has more information on priority ratings for census concepts.
Census usually resident population count
‘Subject population’ means the people, families, households, or dwellings that the variable applies to.
Māori descent uses a 2-level hierarchical classification with level 1 presented in the table below:
Census Māori descent V2.0.0 - level 1 of 2
| Code | Category |
|---|---|
| 01 | Māori descent |
| 02 | No Māori descent |
| 04 | Don't know |
| 99 | Not elsewhere included |
The level 1 residual category ‘Not elsewhere included’ contains the residual categories ‘Response unidentifiable’ and ‘Not stated’. Note, ‘Don’t know’ is a valid response for Māori descent data. Follow the link above the table to examine the classification.
The 2023 Census classification for Māori descent is consistent with that used in 2018 Census.
Standards and classifications has more information on what classifications are, how they are reviewed, and where they are stored, and to provide feedback on them.
Māori descent data is collected from the individual form (paper form question 12).
The wording for the 2023 Census changed from ‘Are you descended from a Māori?’ to ‘Are you descended from Māori?’ as respondents found the original wording awkward and ungrammatical. Other Stats NZ household surveys have also updated this question to remove the ‘a’.
The modes of collection (online and paper forms) had different ways a person could respond.
On the online form:
- Māori descent was a mandatory variable requiring a single response for the respondent to submit the form
- built-in routing functionality directed all individuals who were usually resident in New Zealand at the time of the census to this question.
On the paper form, respondents can skip the question, or tick multiple boxes resulting in a missing or residual response.
Data from the online forms may therefore be of higher overall quality than data from paper forms. However, processing checks and edits were in place to improve the quality of the paper forms.
Stats NZ Store House has samples for both the individual and dwelling paper forms:
Māori descent is a demographic variable. Its uses include:
Data-use outside Stats NZ:
- by Te Puni Kōkiri for monitoring the Māori descent population size, development and wellbeing characteristics, and the number of people eligible for certain benefits
- by the Waitangi Tribunal, Māori Land Court, Te Arawhiti (The Office for Māori Crown Relations) and Te Ohu Kaimoana (Treaty of Waitangi Fisheries Commission) for Te Tiriti o Waitangi matters
- by Te Ngira: Institute for Population Research who use Māori descent to identify changes in household structure across time, contributing to Families and Whānau Status Reports
- to monitor te reo Māori language revitalisation for both the Māori descent and non-Māori descent, in accordance with the Maihi Karauna (the Crown’s Strategy for Māori Language Revitalisation 2019 – 2023).
Data-use by Stats NZ:
- to produce a base estimated resident population for people of Māori descent
- to determine the Māori descent census usually resident population as the base subject population for any standard iwi affiliation output.
Alternative data sources were used for missing and residual census responses and responses that could not be classified or did not provide the type of information asked for. This is an extension of the methodology for the collection of Māori descent in the 2018 Census. The table below shows the distribution of data sources for Māori descent data.
| Data sources for Māori descent data, as a percentage of census usually resident population count, 2023 Census | ||
|---|---|---|
| Source of Māori descent data | Percent | |
| 2023 Census response | 85.3 | |
| Historical census | 9.1 | |
| 2018 Census | 6.5 | |
| 2013 Census | 2.6 | |
| Admin data | 3.5 | |
| Parental data | 0.1 | |
| Deterministic derivation | 0.1 | |
| Statistical imputation | 2.0 | |
| CANCEIS(1) donor's response sourced from 2023 Census form | 0.8 | |
| CANCEIS donor's response sourced from 2018 Census | 0.7 | |
| CANCEIS donor's response sourced from 2013 Census | 0.2 | |
| CANCEIS donor’s response sourced from admin data | 0.3 | |
| CANCEIS donor’s response sourced from parental data | <0.1 | |
| No information | 0.0 | |
| Total | 100.0 | |
| 1. CANCEIS = imputation based on CANadian Census Edit and Imputation System Note: Due to rounding, individual figures may not always sum to the stated total(s) or score contributions. |
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Where appropriate, responses are used from the 2018 and 2013 Censuses to replace missing or residual responses. When this was not possible, the following admin data sources were used:
- Department of Internal Affairs (DIA) Births Register
- Electoral Commission electoral roll.
Electoral roll data was introduced as an admin data source for the first time in the 2023 Census.
If it was not possible to obtain Māori descent information from historical census data or admin data, ‘parental’ data was used. This is where Māori descent values for parents or grandparents can be used to fill missing information on Māori descent for their children or grandchildren.
If a value for Māori descent is still missing, deterministic derivation is used. This is when a valid iwi value on the 2023 Census form, historical census data, or admin data is used to confirm Māori descent.
Statistical imputation was used for any records that remained coded to ‘not stated’ or other residual categories.
Editing, data sources, and imputation in the 2023 Census describes how data quality is improved by editing and how missing and residual responses are filled with alternative data sources (admin data and historical census responses) or statistical imputation. The paper also describes the use of CANCEIS (the CANadian Census Editing and Imputation System) which is used to perform imputation.
Data sources and imputation for Māori descent in the 2023 Census provides more detailed explanations about the methodology and changes from the 2018 Census.
Missing and residual responses represent data gaps where respondents either did not provide answers (missing responses) or provided answers that were not valid (residual responses) in the 2023 Census.
Alternative data sources have been used to fill missing and residual responses in the 2023 and 2018 Censuses. In the 2013 Census, missing and residual responses were left in the data with 9.9 percent of responses being coded to ‘Not stated’.
Overall quality rating: Very high quality
Data has been evaluated to assess whether it meets quality standards and is suitable for use.
Three quality metrics contribute to the overall quality rating:
- data sources and coverage
- consistency and coherence
- accuracy of responses.
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: Very high quality
The quality of all the data sources that contribute to the output for the variable were assessed. To calculate the 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:
- 0.98–1.00 = very high
- 0.95–<0.98 = high
- 0.90–<0.95 = moderate
- 0.75–<0.90 = poor
- <0.75 = very poor.
The high proportion of data received from 2023 Census forms, alongside the high quality of alternative data sources, resulted in a score of 0.99, leading to the quality rating of very high. Refer to the methodology paper for an explanation of how data sources were prioritised.
| Data sources and coverage rating calculation for Māori descent data, census usually resident population count, 2023 Census | |||
|---|---|---|---|
| Source of Māori descent data | Rating | Percent | Score contribution |
| 2023 Census response | 1.00 | 85.25 | 0.85 |
| 2018 Census | 0.95 | 6.54 | 0.06 |
| 2013 Census | 0.93 | 2.56 | 0.02 |
| Admin data | 0.93 | 3.46 | 0.03 |
| Parental data | 0.88 | 0.09 | <0.01 |
| Deterministic derivation | 0.90 | 0.08 | <0.01 |
| CANCEIS(1) nearest neighbour imputation | 0.80 | 2.01 | 0.02 |
| No information | 0.00 | 0.00 | 0.00 |
| Total | 100.0 | 0.99 | |
|
1. CANCEIS = imputation based on CANadian Census Edit and Imputation System Note: Due to rounding, individual figures may not always sum to the stated total(s) or score contributions. |
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Consistency and coherence: Very high quality
Māori descent data is highly consistent with expectations across all consistency checks. Data aligns with historical trends for regional council, territorial authority and local board, and statistical area 2 geographies.
The data source methodology for 2023 Census has extended the 2018 methodology to improve the quality of the data and more accurately reflect the real world. Note that missing and residual responses in the 2013 and prior censuses were left in the data as residual category due to there being no methodology to fill missing Māori descent data.
Accuracy of responses: Very high quality
Māori descent data has no data quality issues that have an observable effect on the data. The quality of coding is very high. Any issues with the variable appear in a very low number of cases (typically less than a hundred). The type of form a respondent used (paper or online, English or bilingual) did not influence their response to the question. Improvement in scanning repair for paper forms reduced the number of responses needing to be sourced from alternative sources.
Māori descent data can be used in a comparable manner to the 2013 and 2018 Censuses and it is recommended that data users familiarise themselves with the changes in methodology between each census.
In the 2013 Census, alternative data sources were not used to fill in missing data and this should be considered when making comparisons with data from the 2013 or earlier censuses. It is recommended that all categories of the classification should be used in time series comparisons so the residual counts in previous years will be clear. When comparing percentages, the ‘Total stated’ population should be used as the denominator.
Regarding the use of Department of Internal Affairs (DIA) Births Register as an admin data source for the Māori descent data, please note the following caveats:
- DIA Births Register could only be used to source Māori descent for individuals born after 01 September 1995, when Māori descent was added.
- Children of Māori descent born overseas are not included in the DIA Births Register.
Comparisons to other data sources
Although surveys and sources other than the census collect Māori descent data, data users are advised to familiarise themselves with the strengths and limitations of the sources before use.
Census aims to be a national count of all individuals with Māori descent while the New Zealand General Social Survey (NZGSS) only collects data from a sample of the population (approximately 8,500 individuals). NZGSS also collects data for people aged 15 and over and therefore is not directly comparable to the census subject population.
To assess how this concept aligns with the variables from the previous censuses, please use the links below:
Contact our Information centre for further information about using this concept.
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