133 Molesworth Street
PO Box 5013
Wellington 6140
New Zealand
T+64 4 496 2000
21 May 2026
Alisha Riley
By email: [FYI request #34198 email]
Ref:
H2026081951
Tēnā koe Alisha
Response to your request for official information
Thank you for your requests under the Official Information Act 1982 (the Act) to the Ministry of
Health – Manatū Hauora (the Ministry) on 22 April 2026. Please note that this letter responds to
your requests relating to the OIA responses H2026080414 and H2026080409.
In response to OIA H2026080414, you requested:
“Thank you for the corrected link to the EHINZ report. Having reviewed the documentation
the Ministry relies upon, I require urgent clarification regarding your refusal to provide the
specific technical and internal data requested under Section 18(d) of the Act. Please reply
by 27 April, 2026.
If the Ministry is claiming that all information provided to the Director-General (DG) is
contained within the public links ( www.health.govt.nz/information-
releases/director-general-of-health-consideration-of-community-water-fluoridation-under-
the-
new-zealand-bill AND ehinz.ac.nz/indicators/water/drinking-water-quality/oral-health-of-
children/ ), please provide the specific page and paragraph numbers for the following, or
alternatively, provide the internal documents requested:
1. The Use of Unadjusted Data :
The provided Metadata
(https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fehinz.ac.nz%2Find
icators%2Fwater%2Fdrinking-water-quality%2Foral-health-of-
children%2F&data=05%7C02%7Coiagr%40health.govt.nz%7C205dac6b092d4e39b8270
8dea0224f79%7C23cec7246d204bd19fe9dc4447edd1fa%7C0%7C0%7C6391242664154
86863%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMD
AwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sd
ata=J%2BdzzAz9aC0bB1FwEdUbxmyXw90fMjY%2BxXMzpk9V6zM%3D&reserved=0)
explicitly states that for the COHS data, "Reliable comparisons... is not possible without
adjusting for a number of demographic variables which are not recorded in the source
data". Furthermore, the EHINZ perspective notes the data are "raw data, unadjusted".
Request:
Please provide the specific internal memo, email, or briefing document acknowledging that
the DG was advised/warned regarding the use of this unadjusted data for the Nov 2024
analysis, or provide the specific mathematical formula the Ministry held to
override/compensate this limitation (and its exact location in the public links).
2. The "Policy Development" Warning:
The EHINZ report explicitly states that "the national statistics from the COHS do not
accurately portray the oral health status... and cannot be used in decision-making or policy
development".
Request:
Please provide any internal briefing, risk assessment, or correspondence where the
Ministry addressed this specific warning prior to using this "unsuitable" dataset to justify
the 14 fluoridation directions.
3. The "Dampening Effect" Omission (Regarding Caries Data):
The EHINZ report clarifies that the "narrowing gap" in caries-free health status is a
"dampening effect" caused specifically by the Auckland region, warning that the national
trend is "unduly influenced" by a single region and does not accurately portray the oral
health status of fluoridated versus non-fluoridated areas.
Request: Please provide the internal briefing or working document where the DG was
informed or where the DG discussed that the national COHS dataset used to calculate the
"proportionality" of the 14 directions was, according to your own source, an inaccurate
portrayal of national trends.
4. The Fluorosis Data Exclusions & "Not Increasing" Metric:
In my March 21 request (Questions 2-5), I asked for internal memos detailing how safety
was assessed for the 0–7 and 31+ demographics, given the 2009 Oral Health Survey
restricted fluorosis data to ages 8–30.
I also requested the longitudinal comparative dataset used to legally conclude on page 13
that fluorosis is "not increasing." You refused these under s18(d). The provided links do
not contain discussion of these age exclusions, nor does it contain a comparative
longitudinal dataset to justify the "not increasing" claim.
Request:
Please provide the specific page and paragraph numbers within the public links where
these specific discussion and the comparative longitudinal dataset can be found. If they
are not in the public link, s18(d) is incorrect, and I request the documents be released or
the omissions explicitly confirmed as original y requested.”
In response to parts 1-3 of your request, please refer to footnote 3 on page 3 of Appendix 1
The
Public Health Agency (PHA) analysis of the 14 directions under the NZBORA through the
following link:
www.health.govt.nz/information-releases/director-general-of-health-consideration-
of-community-water-fluoridation-under-the-new-zealand-bill
In response to part 4 of your request, please refer to page 13 of Appendix 1 in the link provided
to you above. As previously advised (OIA response, H2026080414 refers), this references the
2009 Oral Health Survey results.
Page 2 of 4
In response to OIA H2026080409 you requested:
“Thank you for your response dated 21 April 2026, and for directing me to the publicly
available November 2024 decision package.
I have carefully reviewed the materials at the link provided. As noted in my original
request, the decision package heavily relies on a relative metric, stating there was "40%
less tooth decay." However, the package does not contain the absolute Difference in
Means (the actual number of tooth surfaces/teeth) that I specifically requested. Therefore,
refusing my request under Section 18(d) by pointing to this specific link is factually and
legally incorrect.
To assist the Ministry, I have independently located the raw data tables from the 2009
New Zealand Oral Health Survey published on the Ministry’s website
(https://www.health.govt.nz/publications/our-oral-health-key-findings-of-the-2009-new-
zealand-oral-health-survey). Looking at the data in the 'Protective Factors' spreadsheet
(specifical y the 'DMFT by fluoridation status' tab), the 40% relative reduction translates to
an absolute Difference in Means of less than one single baby tooth (a drop from 2.4 to 1.5
DMFT, per cel s C7 and C8).
My OIA request was specifically seeking the internal governance and briefing documents
to understand if this absolute, physical reality was presented to the Director-General
alongside the 40% relative figure during the NZBORA Section 5 proportionality
assessment.
Since these absolute figures and briefings are definitively not in the November 2024 public
link you provided, I ask that you revisit my original request and provide the following:
1. The Internal Briefings: Please provide the specific internal memos, file notes, or working
documents provided to the Director-General that explicitly outline the absolute Difference
in Means (less than one tooth) for both the child and adult demographics (noting that cell
F18 shows the adjusted difference for "Al , aged 2 years and over" is just 0.8 of a tooth).
2. Confirmation of Non-Existence (s18(e)): If the Director-General was only briefed using
the 40% relative reduction metric, and no internal documents exist showing that the
absolute physical difference in tooth decay was considered in the 2024 NZBORA
Analysis, please explicitly confirm this omission under Section 18(e) of the Act (that the
document does not exist), rather than misapplying Section 18(d).
Thank you for your time. I look forward to receiving either the internal briefing documents
or a formal Section 18(e) confirmation before 27 April, 2026.”
The Ministry can confirm that the requested information does not exist. Therefore, this part of
your request is refused under section 18(g)(i) of the Act as the information is not held by the
Ministry and there are no grounds for believing this information aligns more closely with the
functions of another agency subject to the Act.
As previously advised (OIA H2026080409 and H2026080414 refers), all information provided to
the Director-General of Health in relation to the consideration of community water fluoridation
under the New Zealand Bill of Rights Act 1990 is publicly available through the following link:
www.health.govt.nz/information-releases/director-general-of-health-consideration-of-community-
water-fluoridation-under-the-new-zealand-bill
Page 3 of 4
If you wish to discuss any aspect of your request with us, including this decision, please feel
free to contact the OIA Services Team on:
[email address]. Under section 28(3) of the Act, you have the right to ask the Ombudsman to review any
decisions made under this request. The Ombudsman may be contacted by email at:
[email address] or by cal ing 0800 802 602.
Please note that this response, with your personal details removed, may be published on the
Ministry website at:
www.health.govt.nz/about-ministry/information-releases/responses-official-
information-act-requests
Nāku noa, nā
Barbara Burt
Acting Group Manager, Public Health Policy
Public Health Agency
Page 4 of 4
