Kia ora,

I am writing to request some information under the Official Information Act to help me better understand the data used in the recent "New Zealand Bill of Rights Act 1990 analysis for 14 fluoridation directions."

On page 10 of Appendix 1, the document states: "New Zealand's Oral Health Survey shows that, on average, 40% less tooth decay was experienced among children and adolescents living in communities with fluoridated water..." I am trying to understand how this 40% relative reduction was translated into actual physical metrics for the Director-General during the decision-making process. I am interested in the absolute difference (the Difference in Means) rather than just the relative percentage (the Ratio of Means).

Please note: I am not requesting the raw 2009 New Zealand Oral Health Survey datasets. My request is strictly for the internal briefing documents, or specific page references within the decision package, where these absolute metrics were presented.

Could you please provide the following:

1. Information on Absolute Difference (Children):
Any memo, file note, or working document provided to the Director-General during the drafting of the Memo (or Appendices) that explicitly outlines the absolute Difference in Means for dmft/DMFT or dmfs/DMFS that corresponds to the 40% relative figure quoted on page 10.

2. Information on Adult Efficacy:
Please provide the specific internal documents or briefings provided to the Director-General that show the absolute Difference in Means (for DMFT or DMFS) for the adult demographic (18+) that was considered when assessing the overall benefit of the policy.

3. Location in the NZBORA Assessment: I have reviewed the publicly available November 2024 decision package (the Memo and all Appendices), but I am unable to locate any reference to the absolute Difference in Means for dmft/DMFT or dmfs/DMFS. If these absolute metrics were indeed used to weigh the benefits of the mandate during the s 5 NZBORA assessment, please provide the exact page and paragraph numbers where they are recorded. If these absolute numbers are not recorded anywhere within the Memo or its Appendices, please explicitly confirm this omission.

Thank you for your time and help in clarifying these metrics.
Alisha Riley

Subject:
Clarification of Refusal H2026080409 – Inappropriate use of s18(d) regarding Absolute Metrics

Attention:
OIA Services Team / Barbara Burt

Hi,

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/...). Looking at the data in the 'Protective Factors' spreadsheet (specifically 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 cells 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 "All, 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.

Alisha Riley