governance and production of “expected deaths / excess mortality” analysis in NZ (2015–2025)
SPENCER JONES made this Official Information request to Ministry of Health
Currently waiting for a response from Ministry of Health, they must respond promptly and normally no later than (details and exceptions).
From: SPENCER JONES
Tēnā koutou,
Under the Official Information Act 1982, I request the following information about whether, where, and how expected deaths / excess mortality analysis is produced within NZ government for the period 2015–2025.
1. Holdings confirmation (core question)
Please confirm whether Health NZ holds any documents or datasets that calculate, model, or report:
• expected deaths (baseline mortality),
• excess deaths (observed vs expected),
• or equivalent “expected vs observed” mortality variance measures
for any period between 2015 and 2025 (including weekly or monthly series).
2. If held — identify artefacts (minimal schedule)
If any such analysis is held, please provide a brief schedule identifying for each artefact:
• title (or description),
• date range covered,
• producing business unit,
• whether it is routinely produced,
• and whether it was provided to the Ministry of Health, Ministers, or other agencies.
3. Method documentation
If held, please provide any method notes/technical documentation used to produce expected or excess-mortality outputs (including baselining approach, stratification variables, and revision policy).
4. If not held — governance responsibility
If Health NZ does not hold this analysis, please:
• confirm refusal under the appropriate provision (e.g., s18(g)),
• describe what searches were undertaken (high level is sufficient: repositories/systems and key search terms),
• and identify which agency or entity Health NZ considers most likely to hold responsibility for producing such analysis (if any), including whether this sits with the Ministry of Health, Stats NZ, ESR, a contracted academic group, or another function.
5. Existing public outputs
If Health NZ considers any part of the above is already publicly available (e.g., via Lighthouse or other portals), please provide the exact URLs and the title/name of the relevant tables or datasets.
Kind regards,
Spencer Jones
From: OIA Requests
Kia ora Spencer,
Thank you for your request under the Official Information Act 1982 (the
Act), received by the Ministry of Health on 17 December 2025. You
requested:
"Under the Official Information Act 1982, I request the following
information about whether, where, and how expected deaths / excess
mortality analysis is produced within NZ government for the period
2015–2025.
1. Holdings confirmation (core question)
Please confirm whether Health NZ holds any documents or datasets that
calculate, model, or report:
• expected deaths (baseline mortality),
• excess deaths (observed vs expected),
• or equivalent “expected vs observed” mortality variance
measures
for any period between 2015 and 2025 (including weekly or monthly series).
2. If held — identify artefacts (minimal schedule)
If any such analysis is held, please provide a brief schedule identifying
for each artefact:
• title (or description),
• date range covered,
• producing business unit,
• whether it is routinely produced,
• and whether it was provided to the Ministry of Health,
Ministers, or other agencies.
3. Method documentation
If held, please provide any method notes/technical documentation used to
produce expected or excess-mortality outputs (including baselining
approach, stratification variables, and revision policy).
4. If not held — governance responsibility
If Health NZ does not hold this analysis, please:
• confirm refusal under the appropriate provision (e.g., s18(g)),
• describe what searches were undertaken (high level is
sufficient: repositories/systems and key search terms),
• and identify which agency or entity Health NZ considers
most likely to hold responsibility for producing such analysis (if any),
including whether this sits with the Ministry of Health, Stats NZ, ESR, a
contracted academic group, or another function.
5. Existing public outputs
If Health NZ considers any part of the above is already publicly available
(e.g., via Lighthouse or other portals), please provide the exact URLs and
the title/name of the relevant tables or datasets."
The reference number for your request is H2025077121. As required under
the Act, the Ministry will endeavour to respond to your request no later
than 20 working days after the day your request was
received: [1]http://www.ombudsman.parliament.nz/.
Please be advised that due dates for requests received on 27 November 2025
onwards will take into account the summer holiday period (25 December 2025
to 15 January 2026). Please refer to this guide for an explanation of
the [2]statutory obligations under the Official Information Act 1982.
If you have any queries related to this request, please do not hesitate to
get in touch ([3][email address]).
Ngā mihi
OIA Services Team
Ministry of Health | Manatū Hauora
M[4]inistry of Health information releases
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SPENCER JONES left an annotation ()
Public Annotation – Governance of “expected deaths” and excess mortality analysis in New Zealand
This Official Information Act request sought to clarify how “expected deaths” and excess-mortality estimates are produced, governed, and quality-assured in New Zealand, including which agencies are responsible, what methodologies are used, and whether formal governance or assurance frameworks exist.
In response, Stats NZ and associated agencies explained that excess-mortality analysis is derived primarily from statistical modelling of registered deaths, using standard demographic and time-series methods. The response indicates that:
• There is no single, standalone governance framework dedicated solely to excess-mortality analysis.
• “Expected deaths” are generated as part of routine statistical production processes rather than through a discrete policy or oversight programme.
• Methodological choices (e.g. baselines, trend adjustments, and population changes) are handled within existing statistical quality-assurance systems, rather than through external review panels or health-specific governance bodies.
• Health agencies may use or reference excess-mortality outputs, but responsibility for production and methodological decisions sits primarily within the national statistics function.
The response did not identify:
• A dedicated inter-agency governance group overseeing excess-mortality modelling;
• Formal public-health sign-off processes for how expected-death baselines are set; or
• Regular independent audits or peer-review mechanisms specific to excess-mortality outputs.
For the public record, this OIA clarifies that excess-mortality figures used in public discussion and policy contexts are statistical products rather than governed public-health determinations, and that accountability for their construction lies mainly within existing statistical standards rather than bespoke mortality-governance frameworks.
This distinction may be relevant for readers assessing how excess-mortality figures are interpreted, communicated, or relied upon in health policy, media reporting, or international comparisons.
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