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Iwi statistical standard: September 2017

Introducing the iwi statistical standard

This standard provides guidelines for how to gather, organise, and report iwi and iwi-related groups’ information and statistics. This standard is useful to those who collect iwi information, including iwi, Māori, government agencies, and researchers.

This document provides detailed and technical information for people using and implementing the standard.

See summary of the iwi statistical standard for a less technical commentary.  

Tātai whetū ki te rangi mau tonu, tātai tāngata ki te whenua ngaro noa.

This whakatauki states that while people come and go, the stars in the heavens will always be there. It reminds us that statistics and data remain, even after those they relate to depart.


Whakapapa is central to Māori identity

The concept of whakapapa is central to Māori identity and understanding Māori worldviews. Whakapapa tells a story of where a person comes from, their surroundings, and their relationships with others. Whakapapa connects Māori to their tipuna (ancestors), to the natural environment (eg mountains, waters, or tribal lands), and to each other. It binds the kinship groupings of iwi, hapū, and whānau together. In contemporary settings, these groupings have significance independently and together. Ties to these groupings are different for different people and may develop and change over time or in different situations.

Iwi is part of Māori identity

For many people of Māori descent iwi is only one part of their Māori identity. Because of this, it is beneficial for people using and applying this standard to understand iwi within the wider context of Māori identity.

An iwi is one of the largest kinship groupings and is generally made up of several hapū that are all descended from a common ancestor. Hapū are clusters of whānau (families) where the whānau is usually an extended family grouping made up of children, parents, often grandparents, and other closely related kin.

Changes over time

The concept and definition of iwi are fluid and dynamic. These changes create challenges with defining and classifying iwi for statistical purposes. Discussions about what represents an iwi and which groups and names should be included in iwi lists are ongoing. For these reasons, existing lists of iwi will differ, based on the concept and definition used. This means the groups in Stats NZ’s iwi and iwi-related groups statistical classification (list) may or may not be listed as an iwi elsewhere.

See below for the standard’s definitions of concept and iwi.

Other concepts commonly collected with iwi information

The concepts of Māori descent and ethnicity are often collected together with iwi. ‘Descent’ refers to biological ancestry and ‘ethnicity’ to cultural affiliation.

Māori descent

Māori descent is a biological concept.

There is an important relationship between Māori descent and iwi. Only people who have Māori descent should report their iwi, but this is not always the case. Some people prefer not to acknowledge Māori descent but instead identify only with specific iwi or hapū (Robson and Reid, 2001). Some people also prefer not to provide this information to the Crown.


Ethnicity reflects the ethnic group(s) that people identify with or feel they belong. Ethnicity is a measure of cultural affiliation, as opposed to race, ancestry, nationality, or citizenship (Stats NZ, 2005).

History of the iwi statistical standard

The current classification of iwi was first developed in 1991, followed by the statistical standard in 1994. Minor updates to the iwi classification have generally taken place before each Census of Population and Dwellings but it was not until 2016 that the standard was first reviewed in its entirety (Stats NZ, 2016a).

As part of the 2016 review of the standard for iwi, Stats NZ carried out research and consultation. This involved public submissions and discussion, including hui with iwi and Māori; a review of the academic literature on Māori groupings; and interviews with representatives from key government agencies (Stats NZ, 2016b).

Some key recommendations from this research and consultation were to:

  • highlight that the standard is for statistical purposes (Recommendation 1)
  • update the iwi standard and classification (Recommendation 2)
  • change the process for including groups in the classification (Recommendation 3).

See recommendations from the 2016 review of the statistical standard for iwi (Stats NZ, 2016c) for more information.

We updated the iwi statistical standard to reflect changes required from the review.

Guiding principles

It is important that statistical information collected and reported about iwi and iwi-related groups is based on agreed definitions and principles. This ensures that the statistical information produced is consistent and comparable.

This section describes the purpose of the iwi statistical standard and the concept and definition of iwi, and outlines the standard’s scope.

Purpose of the iwi statistical standard

As a Treaty of Waitangi partner and New Zealand’s national statistics office, Stats NZ plays an important role in ensuring meaningful information about and for Māori is available. The purpose of this standard is to provide guidelines for gathering and reporting iwi and iwi-related groups’ information, so it is valuable and useful to iwi, Māori, and government.

A statistical standard provides a way to classify information for statistical reporting. Such reporting can be used to:

  • provide iwi, iwi-related groups, and Māori with the information they need to support the well-being and development of their people
  • provide government with information about iwi and iwi-related groups to support making policy and decisions
  • compare and integrate iwi information across surveys and collections.


An iwi, or Māori tribe, is one of the largest kinship groupings and is generally made up of several hapū that are all descended from a common ancestor. Hapū are clusters of whānau where the whānau is usually an extended family grouping consisting of children, parents, often grandparents, and other closely related kin.

Definition of iwi

For statistical purposes, an iwi is defined as a whakapapa-based kinship grouping that generally has several hapū and one or more active marae, and a recognised structure that represents the interests of the iwi, such as a rōpū whakahaere, committee, or board.

Note: Different definitions of iwi are used in different contexts. The definition above is used for gathering and reporting iwi and iwi-related groups’ information and statistics.

Scope of this standard

The iwi standard is designed for statistical purposes and is also available for general use. This standard can be used in survey, administrative, and other data collections.

The focus of the iwi standard is whakapapa-based kinship groupings.

Iwi and iwi-related groups statistical classification

Statistical classifications help information on a topic, such as iwi, to be collected and organised in a consistent and meaningful way. This section outlines the scope of the iwi and iwi-related statistical classification, and the conditions for including groups in the iwi and iwi-related classification. It also describes the different classifications that can be used for categorising and reporting responses to an iwi question.

Classification scope

An inclusive approach is used to include iwi and other iwi-related groups (whakapapa-based kinship groupings) in the iwi and iwi-related groups statistical classification.

The iwi and iwi-related groups statistical classification aims to:

  • capture the dynamic and changing nature of iwi and iwi-related groups
  • provide a standard approach for grouping and reporting iwi and iwi-related groups.

Conditions for inclusion

To be included in the classification, groups must be whakapapa-based kinship groupings. Groups should be existing hapū becoming iwi, a collection of hapū, or an iwi-related group.

Groups listed as an iwi, in recognised iwi lists such as a Māori Census, Te Kāhui Māngai, Tūhono, or the Māori Fisheries Act 2004, will be included in the iwi and iwi-related groups statistical classification. In the future, iwi listed in other national and local government agencies’ iwi lists may also be included. These iwi lists will need to be whakapapa-based kinship groupings, and will have undergone an appropriate process for determining which groups to include.

Kinship groups that are not listed as an iwi in recognised iwi lists are encouraged to provide information for a governance group to consider them for inclusion.

This includes information about whether a group has:

  • a shared Māori descent line and its own traditions
  • one or more active marae – these do not need to be physical buildings
  • a recognised structure that represents the interests of the iwi, such as a rōpū whakahaere, committee, or board.

In collaboration with other government agencies and in partnership with Māori, Stats NZ will consider the information a group provides for inclusion.

Note: Population size is not used to decide whether to include a group in the classification. Small groups can be included, but detailed information about them should only be released if confidentiality and privacy conditions are met.

See Confidentiality and privacy section below.

Note: Including a group in the classification does not mean the group is recognised as an iwi in every context – such as in legislation, in other recognised iwi lists, or by other Māori authorities.

Description of classifications

When answering the iwi question, people provide a broad range of responses. Some of these responses belong to other concepts, for example confederations or waka. For this reason, there are separate classifications for categorising responses to the iwi question and for reporting iwi statistics.

Collection classification

All responses to the iwi question are first put into categories using the iwi and iwi-related groups collection (input) classification. This classification is made up of iwi and iwi-related groups that meet the concept and definition in this standard.

The classification has two levels. The first level of the classification lists 15 broad categories (excluding residual categories). These include:

  • 11 categories that group iwi into geographical regions for statistical purposes
  • a category for confederations and waka
  • a category for when iwi are named, but the region is not known
  • a category for when hapū are affiliated to more than one iwi
  • a category for when the region is known, but the iwi is not named.

The second level of the classification lists iwi and iwi-related groups.

The classification also has five extra (residual) categories for:

  • ‘don’t know’ responses
  • refusals to answer the question
  • unidentifiable responses
  • responses unrelated to an iwi or iwi-related group
  • non-responses.

See iwi and iwi-related groups statistical classification.

Reporting classifications

Once responses to the iwi question have been categorised, the categories are put into different classifications for statistical reporting. These are the:

  • iwi classification
  • confederations and waka, iwi not named classification
  • region known, iwi not named classification
  • iwi groupings classification.

Classification updates

The iwi and iwi-related groups statistical classification will be updated as required. For instance, it may need updating in response to a query from an iwi, Māori authority, government agency, or before a specific collection or survey.

Contact if your group is not listed in the iwi and iwi-related groups statistical classification. These groups will be invited to complete a form, which asks for information based on the conditions for inclusion.

We will indicate changes to the classification by updating the version number when the classification is ready to be used.

See classifications and standards under review for the latest news about any changes.

Collecting iwi information

It is important that information about iwi is collected in a consistent way. Using consistent collection approaches improves data quality and the experience of people answering a question on iwi. It also ensures that iwi information is comparable.

This section provides requirements and guidelines for collecting iwi information.

Requirements for collecting iwi information


Collecting information on a person’s iwi is through self-identification. Sometimes a person may be unable to answer a question on their iwi by themselves (eg for children or through death, injury, or sickness). In these cases, a parent, child who is an adult, spouse, partner, or other next-of-kin can answer.

Note: Collecting iwi information through self-identification is different from an iwi register, which usually asks for proof of whakapapa to confirm if a person belongs to an iwi.

Allow for multiple responses

Some people belong to more than one iwi. Where possible, give people the option to provide a minimum of three responses to an iwi question.

It is not appropriate to ask for ‘main’ or ‘most important’ iwi. This is because iwi identity can be fluid for some, with people expressing a range of identities in different contexts. Iwi identity can be dependent on the situation and may develop or change over time.

Collect information on iwi region (rohe)

Some iwi names are common to more than one region (rohe). To help place an iwi in the correct classification category, collect information on the iwi’s location.

Guidelines for collecting iwi information

Type of collection

Collecting iwi information is appropriate for written or electronic self-administered forms, and for interviewer-administered collections.

Electronic forms

When using an online form to collect iwi and iwi-related groups, embed an ‘as-you-type’ list into the response area. This auto-suggests categories as the person begins typing, and can reduce response burden and speed-up processing.

With an as-you-type list, people must still be able to freely type their iwi, if their iwi is not in the list.

Interview-administered collections

If interviewer-administrated collection of iwi and iwi-related groups is required, it is better through a face-to-face interview rather than by telephone. Providing an alphabetical or reference list may be helpful (see Help and guidance below).

Due to potential te reo Māori language limitations of an interviewer, phone collections should be used with caution.

Write-in responses

When asking a question on iwi and iwi-related groups, provide people with the option for writing in their response(s). Doing this themselves is in keeping with the self-identification definition. Choosing from a pre-determined list may prevent people indicating all the iwi they belong to.

It is important people have enough room to write in the full length of their iwi name(s).

Māori descent

Māori descent does not need to be collected with iwi.

However, if Māori descent is collected with iwi in an online or paper form, it is important to document any linking (routing) between the questions. This is important, because in some collections Māori descent is used to link (route) people to the iwi question, so those who mark ‘no’ to Māori descent cannot answer the iwi question. This may be done to reduce the burden on people who are unlikely to belong to an iwi.

To avoid undercounting, all valid iwi responses are counted in some collections, even if a person has marked ‘no’ to Māori descent or has not recorded an answer. In general, each collection needs to provide information about the processes they use for comparison and integration.

Tick box option for people who don’t know their iwi

Providing a ‘don’t know the name of my iwi’ tick box will make answering the iwi name easy for people without that information.

Where to place an iwi question

A question asking for iwi and iwi-related group information is best placed with other identity questions on forms or questionnaires.

Help and guidance

Some collections use a reference list or an alphabetical list of either iwi names or iwi, waka, and confederations to help guide people. Providing reference lists can be helpful for some people, but it may also influence what people report.

Note: Any reference list of iwi should include a statement such as “This list is for reference purposes only, and is not a full list of all iwi or iwi-related groups”.

Question example

See Iwi statistical standard: Question examples for an example of how to ask a question about iwi (PDF, 87 kB).

Classifying responses

After responses to the iwi question have been collected, they must be placed into classification categories. There are however potential difficulties with placing iwi in the correct classification category. Iwi responses can include: differences in spelling; other concepts such as waka, hapū, or geographic markers; different prefixes; or older or traditional iwi names.

This section provides information on some of the common problems and points to consider when classifying responses to a question on iwi.

Common problems for placing responses

Multiple responses

When asking for iwi names, it is expected and acceptable for a person to provide more than one response – up to three is the minimum recommended for systems with limited space. Collect and classify up to three responses in the order they are reported.

In situations where more responses are collected than can be stored, it is not appropriate to assume that the first responses a person records are their ‘main’ or ‘most important’ iwi. For this reason, a random method should be used for reducing responses.

Iwi confederation or waka

If a person provides an iwi confederation or a waka, classify to the correct 'confederations and waka, iwi not named' category.

Iwi name common to more than one region

If a person provides an iwi that is common to more than one region but does not provide the iwi region, classify to the correct 'iwi named, region not known' category.

Hapū name common to more than one iwi

If a person provides a hapū that is common to more than one iwi, classify to the 'hapū affiliated to more than one iwi' category.

Duplicate responses

Hapū and iwi responses

If a person provides an iwi, and provides a hapū classified to that same iwi, only one response should be counted. In this situation, retain the hapū response as this can be used to derive iwi (but iwi responses cannot be used to derive hapū).

If a person provides an iwi and provides a hapū classified to a different iwi, both responses should be counted and retained.

Confederation/waka and iwi responses

If a person provides a confederation or a waka, and provides an iwi belonging to that same grouping, only one response should be counted. In this situation, retain the iwi response.

Other points to consider when classifying responses

Spelling differences

When classifying iwi, it may look as though a person has misspelt their iwi. Take care when classifying these responses. These may be different spellings of the same iwi or they may be the names of different iwi. Some iwi names only differ by one or two letters.

Prefixes differ

Some iwi have different prefixes but look as though they share the same ancestor name. In some cases, the same iwi is being referred to, as the different prefixes are dialectical (eg Kāi and Ngāi). In other cases, the prefixes indicate different iwi (eg Ngāi and Ngāti).

Store responses at response-list level

Where possible, store responses to the iwi question at the response level rather than at the classification (output) level. Doing this allows information to be reported using standard statistical reports and self-defined reports. If it is not possible to store iwi responses in the response-level format, store them at the synonym level (list of likely responses) or at the lowest-level possible.

Stats NZ maintains a response list and a list of synonyms that people can request.

Email if you need this information.

Imputation and substitution

When collecting information on identity (eg iwi), it is best to avoid imputation. Imputation occurs when information is substituted into the place of missing responses.

In some situations where a person does not provide their iwi, it may be appropriate to assign their iwi – using iwi information held from another collection (eg from an administrative collection).

Reporting iwi information

After classifying responses to an iwi question into classification categories, the categories are grouped for reporting purposes.

This section describes how to report information collected from an iwi question.

Statistical reporting

When reporting iwi statistics to government, statistical reporting should be used. This allows iwi and iwi-related groups’ statistics to be compared across surveys and collections.

People provide a broad range of responses when answering the iwi question. These responses are categorised using the iwi collection (input) classification. For statistical reporting, the different concepts should be separated for reporting. This means reporting iwi, confederations and waka, regional responses when an iwi is not named, and iwi groupings separately – classifications are available for reporting each of these concepts.

When reporting iwi, we recommend reporting categories by region or location.

Response-level reporting

When collecting iwi information, people may provide other Māori identity groupings they belong to, such as traditional marae or urban marae, as well as other concepts, such as maunga. Together with iwi responses, we include these in a response list. This list allows people, including iwi, Māori, researchers, to group and report responses from an iwi question in a way that is useful to them.

Iwi response list

When collecting iwi information, it is possible to create a response list using written responses from the iwi question. A response list can be used to report the majority of responses to the iwi question because the list is made up of written responses that have not been grouped into classification categories.

Stats NZ has developed an iwi response list that is made up of census iwi responses that are based on Māori descent. Responses with at least 10 counts are a separate category in the response list. Because we created the response list using the actual written responses from people, categories include both whakapapa-based kinship groupings and non-kinship Māori groupings.

The response list is broader than the iwi and iwi-related groups classification because it is actual responses – some categories from the response list are grouped together in the classification. For instance, hapū responses are separate categories in the response list, but are grouped together with their iwi in the classification. As a result, counts may differ for the response list and the classification.

Note: We are preparing a paper on the methods used for producing response-list reports.

Other points to consider when reporting about iwi

Reporting multiple responses

People often provide more than one iwi name. This means the total number of iwi responses is greater than the total number of people reporting their iwi.

Time series

Stats NZ will make a concordance (mapping) that links iwi categories between different versions of the classification. This shows where iwi groups have been split, or combined, between the different classification versions.

Time series provide a count of responses over the different years a survey or collection is run. Adding new iwi and iwi-related groups to the classification may affect time-series information.

Time series may change when the classification is updated, as some responses will go to a new category or categories. This decreases the counts in the iwi categories they came from.

Back-casting data may be used when a new iwi or iwi-related group is added to the classification and its information from past surveys or collections is available. Responses from these collections are counted for the separate category and are not shown in the former iwi category count. This enables the new group to have its information available from past surveys.

Collecting iwi in long-running surveys

When collecting iwi in surveys that run for several years, allow for changes in how people self-identify their iwi. There may be inconsistencies in different surveys, or at different times, because of the collection context and other factors.

Web-based classification tool

Ariā is a web-based classification tool that is currently being developed. People will be able to access the classifications and the iwi response list from here. In the future, people will be able to create their own reports in Ariā by choosing the classification or list categories they require.

Access Ariā here. 

Confidentiality and privacy

Iwi information should only be reported and shared if the counts do not cause a privacy or confidentiality concern by allowing a person to be identified. This means smaller groups can access their counts, but they might not be able to access more-detailed information about their group, such as age, sex, occupation, or areas where people live.

See Privacy, security, and confidentiality of information supplied to Statistics NZ for Stats NZ's guidelines around confidentiality and privacy.


Clusters of whānau (families) where the whānau is usually an extended family grouping consisting

iwi-related groups
Kinship groupings with a shared Māori descent line, such as a waka grouping or confederation.

A traditional meeting place for whānau, hapū, and iwi members (Abridged from: Te Kāhui Māngai).

Mountain, mount, peak (Source: Māori dictionary)

non-kinship Māori grouping
Non-kinship Māori groupings connect people of Māori descent, but are not bound by ancestral lineage. Non-kinship Māori groupings are typically locality-based.

Ancestor, grandparent, grandfather, grandmother (Source: Māori dictionary).

rōpū whakahaere
Management group, organisational committee (Source: Māori dictionary).

urban marae
Non-traditional marae, not specifically associated with any particular hapū. Urban marae often serve as meeting places for the wider community and are also commonly called community, ngā hau e whā, ngā mātā waka, or pan-tribal marae (Abridged from: Te Kāhui Māngai).

Allied kinship groups descended from the crew of a canoe that migrated to New Zealand and now occupying a set territory (Source: Māori dictionary).

Genealogy, genealogical table, lineage, descent. Reciting whakapapa was, and is, an important skill and reflects the importance of genealogies in Māori society – for leadership, land and fishing rights, kinship, and status. It is central to all Māori institutions (Abridged from: Māori dictionary).

A family or extended family (Source: Te Kāhui Māngai).


Moorfield, J (nd). Māori dictionary. Retrieved from

Robson, B, & Reid, P (2001). Ethnicity matters: Māori perspectives. Retrieved from

Stats NZ (2005). Statistical standard for ethnicity. Retrieved from

Stats NZ (2016a). Review of the statistical standard for iwi: Summary of key points. Retrieved from

Stats NZ (2016b). Discussion of findings from the 2016 review of the statistical standard for iwi. Retrieved from

Stats NZ (2016c). Recommendations from the 2016 review of the statistical standard for iwi. Retrieved from

Te Puni Kōkiri (nd). Te Kāhui Māngai: Directory of iwi and Māori organisations. Retrieved from


Stats NZ (2017). Iwi statistical standard: September 2017. Retrieved from

ISBN 978-1-98-852830-4 (online)
Published 29 September 2017

Updated 21 February 2018

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