Appendix Two: Using data from the IDI and What About Me? survey

The IDI

The IDI is a large research database that holds de-identified data about people and households. This includes data that government agencies and NGOs
Non-government organisationsView the full glossary use to manage the services they provide to the public (administrative data) and data from surveys run by Stats NZ.

We used IDI data because:

  • it links de-identified data from different sources about individuals and households so we can see the range of services that individuals and whānau
    Whānau refers to people who are biologically linked or share whakapapa. For the Monitor’s monitoring purposes, whānau includes parents, whānau members living with tamariki at the point they have come into care View the full glossary     receive
  • it means we can follow a range of outcomes for tamariki
    Children (plural) aged 0-13 yearsView the full glossary     and rangatahi
    Young person aged 14 – 21 years of ageView the full glossary     both while they are involved in the oranga tamariki system and later after they have left the system and move into adulthood.

Stats NZ has strict criteria for using the IDI so people’s information is protected. You can find more detail about how Stats NZ keeps data safe on its website.152

Stats NZ disclaimers about using the IDI

We are also required to make the following disclaimers about data from the IDI.

Access to the data used in this study was provided by Stats NZ under conditions designed to give effect to the security and confidentiality provisions of the Data and Statistics Act 2022. The results presented in this study are the work of the author, not Stats NZ or individual data suppliers.

These results are not official statistics. They have been created for research purposes from the Integrated Data Infrastructure (IDI) which is carefully managed by Stats NZ. For more information about the IDI please visit: https:// www.stats.govt.nz/integrated-data/

The results are based in part on tax data supplied by Inland Revenue to Stats NZ under the Tax Administration Act 1994 for statistical purposes. Any discussion of data limitations or weaknesses is in the context of using the IDI for statistical purposes and is not related to the data’s ability to support Inland Revenue’s core operational requirements.

Technical definitions of IDI indicators

Our analysis considered people who were living in Aotearoa
New ZealandView the full glossary during 2023. We grouped this population based on their age at the end of 2023:

  • Tamariki and rangatahi aged 0–17 during 2023. 
  • Young adults aged 18–25 or 27–30 during 2023.

We also made comparisons with results from our analysis for people who were living in Aotearoa during 2022.

We also grouped the population by level of involvement with Oranga Tamariki. We used these age groupings because:

  • tamariki and rangatahi aged 0–17 may be currently involved in the oranga tamariki system
  • young adults aged 18–25 who were in care or custody may be eligible for Transition Support Services during the year
  • we wanted to understand what life outcomes are like for adults aged 27–30 who were involved in the oranga tamariki system as children.

We show the framework for classifying interaction with the oranga tamariki system below.

Grouping the population for this report
No Oranga Tamariki involvement Involved with Oranga Tamariki
No Oranga Tamariki involvement Care and protection and/or youth justice intervention Care or custody
No Oranga Tamariki involvement Care and protection and/or youth justice intervention Care or custody (ineligible for Transition Support Services)153 Care or custody (eligible for Transition Support Services)
No Oranga Tamariki involvement Care and protection intervention Youth justice intervention Care and protection custody Youth justice custody
Definition of population groups
  No Oranga Tamariki involvement Care and protection intervention Youth justice intervention Care and protection custody Youth justice custody
Aged 27–30 Never had a report of concern or received a youth justice intervention as a child  Had a report of concern, a child and family assessment or an FGC in their lifetime but never received youth justice intervention or came into care or custody  Received youth justice intervention (FGC, supervision order) in their lifetime but no care or custody placement  Spent time in a care and protection custody placement in their lifetime but not in youth justice custody  Spent time in youth justice custody in their lifetime 
Aged 0–17  Did not have a report of concern or receive care and protection or youth justice intervention or spend time in care or custody in 2023  Had a report of concern, a child and family assessment or an FGC in 2023 but did not come into care or custody or receive youth justice intervention  Received youth justice intervention in 2023 but no care or custody placement  Spent time in a care and protection custody placement in 2023 but not in youth justice custody  Spent time in youth justice custody in 2023 
Definition of population groups
  No Oranga Tamariki involvement Care and protection and/or youth justice intervention Care or custody (ineligible for Transition Support Services) Care or custody (eligible for Transition Support Services)
Aged 18–25 Never had a report of concern, never received care and protection or youth justice intervention and never entered care or custody as a child Had a report of concern, a child and family assessment or an FGC in their lifetime and/or received youth justice intervention but never came into care or custody Spent time in a care and protection custody placement or in youth justice custody and ineligible for Transition Support Services Spent time in a care and protection custody placement or in youth justice custody and eligible for Transition Support Services

Defining disability

For this work, a person was defined as disabled if they did any of these things.

  • Responded to questions154 in Census 2023, Census 2018 or a social survey as experiencing disability.
  • Received a Disability Allowance or was a child whose parent received a Child Disability Allowance on their behalf.
  • Received an Invalid’s Benefit or Supported Living Payment (excluding carers).
  • Received Ongoing Resourcing Scheme support or School High Health Needs funding.
  • Was a Disability Support Services client.

Definitions of measures

The table below contains definitions for the measures we used in this report. You can find full technical definitions for measures and the software code we used to produce the measures on our repository site with a summary of measure definitions.155

Measures marked with an asterisk * used a code module. The code modules initiative is an effort backed by government agencies and non-government users of the IDI to make the integrated data assets easier to use and understandable for everyone, including nontechnical people.156 Code modules contain high-quality code and documentation for foundational measures needed by researchers.

Intergenerational measures
Measure Definition
Intergenerational Oranga Tamariki involvement

For young adults aged 27–30.
We looked at young adults who were recorded as parents for registered births. This includes both children born in New Zealand or born overseas but legally adopted in New Zealand.

One or more of their tamariki are recorded as having involvement with Oranga Tamariki at some point within their lives until the end of the relevant year.

We looked at both where:

  • one or more tamariki have had at least one spell in the care or custody of Oranga Tamariki.
  • one or more tamariki had an interaction with Oranga Tamariki but did not enter care of custody – for example, a report of concern was received, a child and family assessment was made or an FGC was held.
Health measures
Measure Definition
GP visit

For tamariki and rangatahi aged 0–17 or for young adults aged 18–25 or 27–30.
An individual has consulted a GP at their registered practice at least once within the relevant year. This measure is limited to those enrolled with a PHO157 as it does not include consultations with GPs made as a casual patient.
Mental health and addiction service use

For tamariki and rangatahi aged 0–17 or for young adults aged 18–25 or 27–30.
An individual accessed secondary public inpatient or community mental health and addiction services at least once in the relevant year. Note this measure does not include primary healthcare settings such as GP consults, which may also be used to address mental health or addiction issues.
Self-harm hospitalisation

For tamariki and rangatahi aged 0–17 or for young adults aged 18–25 or 27–30.
An individual was hospitalised at least once during the relevant year with a diagnosis that indicated intentional self-harm or self-injury with undetermined intention.
Education measures
Measure Definition
School attendance*

For tamariki and rangatahi aged 0–17.
Grouped into primary/intermediate and secondary school attendance. For students enrolled at state or state-integrated schools, their attendance in term 1 within the relevant year. For each student, attendance is recorded for each half-day as attending, justified absence or unjustified absence. The half-days a student was recorded as attending were divided by the total of half-days and ranked into bands of:

  • regular attendance (present for 90% or more of the term)
  • irregular absence (present for 80% or more of the term but less than 90%)
  • moderate absence (present for 70% or more of the term but less than 80%)
  • chronic absence (present for less than 70% of the term).
NZQCF level 2+ attainment*

For rangatahi aged 18.
An individual has attained a level 2 qualification or above from the New Zealand Qualifications and Credentials Framework (NZQCF) by the end of the year in which they turn 18. This is limited to rangatahi who were enrolled in school at some point after turning 15. For many individuals, the qualification will be NCEA level 2 or 3 attained at secondary school. For others, the qualification may be a certificate or diploma from other education providers.
Highest qualification*

For young adults aged 27–30.
The highest level of qualification an individual attained by the end of the relevant year. Qualifications are grouped by NZQCF levels as secondary (level 1–3), tertiary (level 4–6) or university (level 7–10). Note that qualifications attained outside of New Zealand may not be included in this measure unless an individual recorded them through Census 2013 or 2018.
Social support measures
Measure Definition
Supported by main benefit*

For young adults aged 18–25 or 27–30.
An individual received a main benefit for the whole year, for example the individual has been continuously receiving a main benefit for a spell of 365 days or more during the year (counting only days within the year). Main benefits include Sole Parent Support, Jobseeker Support, Supported Living Payment, Young Parent Payment and Youth Payment.158
Emergency housing spell

For young adults aged 18–25 or 27–30.
An individual was the principal applicant for an Emergency Housing Special Needs Grant at least once within the relevant year or within their adult lifetime.
Other measures
Measure Definition
Driver licence*

For young adults aged 18–25 or 27–30.
An individual held a current New Zealand restricted licence or class 1 full licence (car licence) or class 6 full licence (motorcycle licence) at the end of the relevant year. This excludes licences that are not current, for example, licences that are expired or suspended, and excludes people who only hold overseas licences.
In employment

For young adults aged 27–30.
An individual received income from wages, salary or paid parental leave during the month. The proportion of each group who were employed each month was measured across the year. For simplicity, we present the average taken across the year.
Prison/home detention

For young adults aged 18–25 or 27–30.
An individual experienced a prison spell (including remand) or home detention at least once since they turned 18. Note this only includes incarceration or home detention in New Zealand.

Numbers of Māori in each age group and level of involvement with Oranga Tamariki

Number of Māori aged 0–17 in each group in 2023
No involvement with Oranga Tamariki in their lifetime 214,500
Involvement with Oranga Tamariki in their lifetime but not within the last year 76,710
Had a report of concern in the last year but no further involvement with Oranga Tamariki 9,279
Had a child and family assessment made within the last year but no further involvement with Oranga Tamariki 12,765
Had an FGC held for them but did not enter care 2,664
Received youth justice intervention in the last year but no care or custody placement 717
Spent time in a care and protection custody placement in the last year but not in youth justice custody 2,802
Spent time in youth justice custody in the last year 192
Spent time in both care and protection and youth justice custody in the last year 129
Number of Māori aged 18–25 in each group in 2023
No involvement with Oranga Tamariki in their lifetime 68,418
Had a report of concern or received care and protection or youth justice intervention as a child (child and family assessment, FGC, youth justice supervision order) but never in care or custody (ineligible for Transition Support Services) 47,184
Spent time in care and protection and or youth justice custody (in eligible for Transition Support Services) 5,850
Spent time in care and protection or youth justice custody (eligible for Transition Support Services) 2,268
Number of Māori aged 27–30 in each group in 2023
No involvement with Oranga Tamariki in their lifetime 34,251
Had a report of concern in their lifetime but no further involvement with Oranga Tamariki 2,760
Had a child and family assessment made in their lifetime but no further involvement with Oranga Tamariki 9,279
Had an FGC held for them in their lifetime but did not enter care 2,760
Received youth justice intervention (FGC, supervision order) in their lifetime but no care or custody placement 3,501
Spent time in a care and protection custody placement in their lifetime but not in youth justice custody 3,252
Spent time in youth justice custody in their lifetime 375
Spent time in both care and protection and youth justice custody in their lifetime 564

What About Me? survey

What About Me? was a nationwide survey of rangatahi aged 13–18. It was done on behalf of the Ministry of Social Development in 2021.

Just under 8,000 rangatahi responded to questions about their health, wellbeing, whānau and community. This included just over 7,000 rangatahi in years 9–13 at school and a further 500 rangatahi of the same age in the community.

We were only able to access the 2021 dataset from Stats NZ for those rangatahi who completed the survey in schools. This means the measures are not representative of rangatahi who do not regularly attend school. This is an unfortunate limitation because IDI measures show that some groups of rangatahi in the oranga tamariki system are less likely to regularly attend school and are therefore less likely to have their views represented in the school sample.

The survey included questions about ethnicity and involvement with Oranga Tamariki. This enabled us to understand:

  • how tamariki and rangatahi Māori who had been involved with Oranga Tamariki159 felt about many aspects of their life
  • how this compared to those who had never been involved with Oranga Tamariki.160

Subjective wellbeing measures are particularly important because most administrative data comes from people’s interactions with government agencies and services – they don’t tell us anything about people’s views on their own lives.

The questionnaires for the What About Me? and Youth2000 surveys were merged for the 2025 Youth Health and Wellbeing Survey.161 The Ministry of Social Development conducted this round of the survey in early 2025 and intends to repeat it every three years. At the time of writing, only a summary report of the 2025 results has been made available. We will refer to detailed data from this survey in our future reports.

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Footnotes

152 stats.govt.nz/integrated-data/how-we-keep-integrated-data-safe/
153 Eligibility for Transition Support Services from Oranga Tamariki is based on how old tamariki
Children (plural) aged 0-13 yearsView the full glossary and rangatahi
Young person aged 14 – 21 years of ageView the full glossary were when they left custody or care and how long they were in care of custody. To be eligible for Transition Support Services, rangatahi must have been in care or custody for at least three months continuously after the age of 14 years and 9 months. For eligible rangatahi, Transition Support Services can continue to support a transition into adult life between 15 to 25 years of age. orangatamariki.govt.nz/children-in- our-care/transition-support-service 
154 Washington Group Short Set questions on functional disability. washingtongroup-disability.com/question-sets/wg-short-set-on-functioning-wg-ss
155 github.com/nz-social-investment-agency/Children-interacting-with-the-OT-system
156 For more detail about code modules, see stats.govt.nz/integrated-data/code-modules-initiative
157 For more details on PHOs, see tewhatuora.govt.nz/for-health-providers/primary-care-sector/primary-health-organisations
158 Our measure used the Ministry for Social Development Income Support Payments code module and all benefits included in the main benefit portion.
159 The group of What About Me? survey respondents involved with Oranga Tamariki includes any tamariki and rangatahi who answered ‘yes’ to ‘have you or anyone in your family every been involved with Child Youth and Family Services (CYFS) or Oranga Tamariki?’ This includes those who have had a social worker visit them or their family, had an FGC or been in care.
160 The survey sample included responses from 1,395 Māori with no involvement with Oranga Tamariki and 606 Māori with had been involved with Oranga Tamariki.
161 See footnote 5.