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
show quoted sections
From: OIA Requests
Tēnā koe Spencer
Thank you for your request under the Official Information Act 1982 (the
Act) to the Ministry of Health - Manatū Hauora (the Ministry) 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.”
Your request asks for information which is more closely connected to the
functions of Health New Zealand – Te Whatu Ora. For this reason, I have
decided to your request under section 14(b)(ii) of the Act. You can expect
a response from Health New Zealand in due course. Their contact email is
[1][email address].
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: [2][email address] or by calling 0800
802 602.
Ngā mihi
OIA Services Team
Ministry of Health | Manatū Hauora
M[3]inistry of Health information releases
show quoted sections
References
Visible links
1. mailto:[email address]
2. mailto:[email address]
3. https://www.health.govt.nz/about-ministr...
SPENCER JONES left an annotation ()
This Official Information Act request seeks clarity about who in New Zealand is responsible for producing, governing, and holding analysis of “expected deaths” and “excess mortality”, and what information actually exists.
During the COVID-19 period and afterwards, excess-mortality analysis has been widely cited internationally as a high-level indicator of population-level impacts. In New Zealand, however, it is often unclear:
• whether such analysis is routinely produced;
• which agency is responsible for it;
• what methods and assumptions are used; and
• whether any analysis exists beyond high-level commentary.
This request does not assume that excess-mortality analysis proves or disproves any particular outcome. Its purpose is more basic and procedural: to establish what information exists, who holds it, and how it is governed.
That matters for several reasons.
First, accountability and transparency.
If expected-deaths or excess-mortality analysis is being produced or relied upon by public agencies, the public is entitled to know:
• what datasets and methods are used;
• what limitations apply; and
• which agency is accountable for its accuracy and interpretation.
If such analysis is not being produced, that is also a material fact in evaluating how population-level impacts are monitored.
Second, clarity of agency responsibility.
The Ministry of Health transferred this request to Health New Zealand – Te Whatu Ora under section 14(b)(ii) of the OIA, indicating the information is more closely connected to Te Whatu Ora’s functions. This raises an important governance question:
is excess-mortality analysis considered part of health system monitoring, statistical production, policy oversight, or something else?
Public clarity about agency roles helps prevent responsibility gaps and improves trust in official reporting.
Third, methodological transparency.
Expected-deaths modelling depends on assumptions (such as population structure, seasonality, and baseline trends). Understanding whether such methods are documented, reviewed, or standardised is essential for informed public discussion and responsible use of statistics.
Finally, historical record.
This request covers 2015–2025 to allow comparison across pre-pandemic, pandemic, and post-pandemic periods. Establishing what information exists now ensures an accurate public record for future researchers, journalists, and policymakers.
In short, this request is about knowing what analysis exists, who is responsible for it, and how it is governed.
That is a core purpose of the Official Information Act and a prerequisite for meaningful public accountability.
From: hnzOIA
Tçnâ koe,
Thank you for your email.
Under the Official Information Act (OIA), agencies are required to respond
to requests for official information as soon as reasonably practicable and
no later than 20 working days after receiving them.
Please note that the period from 25 December 2025 to 15 January 2026
(inclusive) is not counted as working days under the OIA. As a result, any
OIA requests received on or after 29 November 2025 may take longer to
process than usual, as the maximum response timeframe may extend into the
new year.
If your request is for data that Health NZ holds, have you checked
[1]Lighthouse first to see if the data you are seeking is already
published?
Lighthouse is a searchable catalogue that makes a range of data and
analytics products available to New Zealanders to enable easier, faster
access to insights about health services.
You can find further information about how OIA timeframes are calculated,
including the Ombudsman’s OIA calculator, at the link below:
[2]Official information calculators | Ombudsman New Zealand
We will provide a response to your request in line with the statutory
timeframes set out in the OIA.
We appreciate your understanding and patience during this time.
Ngâ mihi,
Health NZ | Te Whatu Ora.
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References
Visible links
1. https://www.tewhatuora.govt.nz/for-healt...
2. https://www.ombudsman.parliament.nz/agen...
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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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