Provisional Mortality Statistics methodology

This publication contains preliminary death counts by date of occurrence for Australia.

This series was introduced in June 2020 in response to the COVID-19 pandemic in Australia. The report provides an early indication of the pattern of mortality. There are many factors that may influence counts of deaths on a week to week basis, so deviations from baseline counts for individual weeks should be treated with caution.

The results for all past publications can be accessed by selecting ‘View all releases’ in the header of this publication.

Complete analysis of mortality data is only possible when the majority of death records (both coroner and doctor) are received and processed. Death counts in this report will not be comparable with those reported in Deaths, Australia or Causes of Death, Australia. Differences are explained in more detail throughout the methodology. Death counts in this report may also not be comparable with other data sources based on the provisional data. Until it has been finalised, the data is subject to continuous quality improvement.

For more detailed analysis of mortality statistics up to 2024, please refer to the Deaths and Causes of Death reports linked above. 2025 data will be published towards the end of 2026.

In scope:

• deaths occurring and registered for the first time in Australia
• deaths of overseas visitors and temporary residents
• deaths in Australian Territorial waters
• deaths in Australian Antarctic Territories or other external territories (including Norfolk Island)
• deaths in transit (e.g. on a ship or plane) if registered at the next Australian port of call
• deaths of Australian nationals employed overseas at Australian diplomatic missions and consular offices (i.e. deaths of Australian diplomats while overseas), where able to be identified. This includes historical legations, which are no longer in operation
• registration of deaths that occurred in earlier years.

Not in scope:

• deaths occurring overseas, even if remains are repatriated
• deaths of foreign diplomatic staff in Australia (if known)
• stillbirths (or fetal deaths) (covered in perinatal statistics only).

Since 1 July 2016, deaths registered on Norfolk Island have been included in national statistics under the Norfolk Island Statistical Area 2 (SA2) code under the Norfolk Island Legislation Amendment Act 2015. Prior to this, only deaths of Norfolk Island residents occurring in Australia were included, and their usual residence was recorded as ‘overseas’.

The registration of deaths is the responsibility of the Australian states and territories Registries of Births, Deaths and Marriages (RBDMs). Deaths occurring in "other territories" of Australia are registered by RBDMs in one of the eight states and territories. The exception to this is deaths occurring on Norfolk Island which are registered by the Norfolk Island Registry of Births, Deaths and Marriages which sits within the Norfolk Island Regional Council. Deaths for "other territories" are included in the death statistics for Australia.

When a death occurs, the cause of that death is either certified by a doctor using a Medical Certificate of Cause of Death (MCCD), or the death is referred to a coroner for further investigation. For doctor certified deaths, information about the cause of death is supplied by the medical practitioner certifying the death via the MCCD (or MCCPD for perinatal deaths). Other information about the deceased is supplied via the Death Registration Form (DRF), which is informed by a relative or other person acquainted with the deceased, or by an official of the institution where the death occurred. Registrars require information from both sources to complete a death registration. It should be noted that legislative requirements for registering a death differ across jurisdictions and this can impact on the timeliness of registration and reporting.

Information is provided to the Australian Bureau of Statistics (ABS) by individual Registrars for processing, coding and compilation into aggregate statistics. Registrars report all deaths that were registered in a month at the start of the following month.

The following diagram shows the process undertaken in producing causes of death statistics in Australia. 

This publication draws extensively on information provided freely by the Australian state and territory Registries of Births, Deaths and Marriages and the Norfolk Island Regional Council. Their continued cooperation is very much appreciated: without it, the wide range of vital statistics published by the ABS would not be available.

Information received by the ABS is treated in strict confidence as required by the Census and Statistics Act 1905.

Data in this report includes all deaths registered by the end of a given month, by date of occurrence. When looking to measure change over time, the completeness of data for the most recent reported period is important.

When data is received each month by the ABS, the lag between the date of death and the date of registration means that approximately 40-50% of reported registrations are of deaths that occurred in the month being reported. The remainder are deaths that occurred in earlier months.  

For deaths which are doctor certified, approximately 95% of registrations are received after a second month of reporting. This is considered sufficiently complete to enable meaningful comparison with historical counts, noting that the level of completeness will be higher for the start of any given month than the end of that month. 

For coroner certified deaths, the proportion of registrations reported after a second month is lower, as it takes longer for coroners to certify deaths due to the complexity of investigations. Coroner certified deaths are included in the all-cause data and this may lower the completeness rate for more recently published weeks (see the Data Release section of the methodology for more information on what data is available based on certification type).

All conditions listed on the medical certificate of cause of death (MCCD) are coded to the International Classifications of Diseases, 10th revision (ICD-10) (see Standards and classifications section of the methodology for more information). ICD-10 codes are assigned to all conditions on a MCCD and rules applied to select an underlying cause of death. The underlying cause of death is defined by the WHO as either the disease or injury that initiated the train of morbid events leading directly to death or the circumstances of the accident or violence that produced the fatal injury. Data presented in this publication is tabulated according to the underlying cause of death.

In response to the COVID-19 pandemic in 2020, the WHO issued the ICD emergency codes U07.1 COVID-19, virus identified; U07.2 COVID-19 virus not identified; and U10.9 Multisystem inflammatory syndrome associated with COVID-19. These codes are used when assigning causes to confirmed or suspected COVID-19 deaths. Due to the public health importance of COVID-19, the WHO directed that the new coronavirus strain be recorded as the underlying cause of death, i.e. the disease or condition that initiated the train of morbid events, when it is recorded as having caused death.

• Deaths due to COVID-19: A death directly due to COVID-19 is defined by the WHO as a death resulting from a clinically compatible illness, in a probable or confirmed COVID-19 case, unless there is a clear alternative cause of death that cannot be related to COVID disease (e.g. trauma). There should be no period of complete recovery from COVID-19 between illness and death.
• COVID-19 related-deaths (dying with COVID-19): A COVID-19 related death is one where there is a disease or injury pathway to death that is not directly caused by the virus. For example, a person may have late stage cancer that has metastasised extensively causing organ damage leading to death. This person may also have contracted COVID-19. While the virus or its complications may have negatively impacted health in an immuno-compromised person, the virus itself did not cause the terminal event leading to death (e.g. organ failure caused by metastases).

Deaths due to COVID-19 are not included in deaths due to respiratory diseases or any of the other specified causes included in this report. More detail on how COVID-19 is coded in causes of death statistics is outlined in section on Coding of COVID-19 from the Medical Certificate of Cause of Death.

Excess mortality is an epidemiological concept typically defined as the difference between the observed number of deaths in a specified time period and the expected numbers of deaths in that same time period. During the COVID-19 pandemic estimates of excess death measurements have been used to provide information about the burden of mortality potentially related to the COVID-19 pandemic, including deaths that are directly or indirectly attributed to COVID-19. The expected number of deaths in a given year is best measured through statistical models that use historical counts of deaths to estimate an expected number of deaths for a given year. Refer to the Articles related to Causes of death for more detailed discussion on excess mortality.

In line with the ISO (International Organization for Standardisation) week date system, weeks are defined as seven-day periods which start on a Monday. Week 1 of any given year is the week which starts on the Monday closest to 1 January, and for which most of its days fall in January (i.e. four days or more). Week 1 therefore always contains the 4th of January and always contains the first Thursday of the year. Using the ISO structure, some years (e.g. 2015, 2020 and 2026) contain 53 weeks.

Age-standardised death rates (SDRs) enable the comparison of death rates over time and between populations of different age-structures. The ABS uses the direct method of age-standardisation which allows for valid comparisons of mortality rates between different study populations and across time. This method was agreed to by the ABS, Australian Institute of Health and Welfare (AIHW) and other stakeholders. For further information see: AIHW (2011) Principles on the use of direct age-standardisation in administrative data collections: for measuring the gap between Indigenous and non-Indigenous Australians. Cat. no. CSI 12. Canberra: AIHW.

SDRs for specific causes of death with fewer than a total of 20 deaths have not been published due to issues of robustness. For further information, see Appendix: Principles on the use of direct age-standardisation, from Deaths, Australia, 2010.

SDRs in this publication have been calculated using quarterly estimated resident population (ERP) published in National, state and territory population. See Revision status in the Methodology for details of the status of quarterly population data used for calculating baseline rates. The quarterly estimates used for calculating weekly rates for the relevant year are as follows:

• weeks 1-13 - Mar quarter ERP
• weeks 14-26 - Jun quarter ERP
• weeks 27-39 - Sep quarter ERP
• weeks 40-53 - Dec quarter ERP.

Mortality rates derived from administrative data counts may be subject to natural random variation, especially for small counts. Confidence intervals (CIs) for an SDR can help quantify this variability. CIs in this publication indicate a 95% probability that the 'true' SDR is contained within the lower and upper limits of the confidence interval. CIs have been calculated using the standard method and formulae can be sourced from Breslow and Day (1987) in the 'Statistical methods in cancer research' publication. Further information on the calculation of CIs can also be found on the METeOR website (see National Indigenous Reform Agreement: PI 08 - Tobacco smoking during pregnancy, 2016).

The ABS publishes two regular reports that provide preliminary information on mortality - Provisional Mortality Statistics and Deaths due to acute respiratory infections in Australia. These reports provide information on different time periods and serve different purposes.

Provisional Mortality Statistics focus on monitoring patterns of mortality (by all-causes and specified leading causes of death). Data must be sufficiently complete to detect such changes, and as such these reports are only released once the majority of deaths that occurred in a particular period have been registered and reported.

Deaths due to acute respiratory infections in Australia articles focus on all deaths registered and reported with selected acute respiratory infections (COVID-19, influenza and RSV) written on the death certificate up until a specified time. This publication includes important information about these deaths, including demographic details. While it is recognised data will be incomplete, it can still indicate emerging trends or changes among deaths caused by these acute respiratory infections. 

This report contains statistics compiled using different methods to those used when compiling annual data on deaths and causes of death.

Key differences include:

1. Data for cause-specific mortality includes only doctor certified deaths (as with previous reports) due to the additional time taken to complete complex coronial investigations. Data for all-cause mortality includes deaths certified by both a doctor and a coroner as do the annual datasets. This is a change from monthly mortality publications prior to April 2022 release, for which all-cause mortality only included deaths certified by a doctor.
2. This report is based on the date the death occurred. Annual reports are based on the date of registration.
3. This report is based on the state or territory of registration. Annual reports are based on the state or territory of usual residence of the deceased.
4. Data in this report is provisional. Data released in annual reports is final (except for revisions for coroner referred deaths). 

Causes of death are either certified by a doctor or a coroner. In Australia approximately 86-89% of deaths are certified by a doctor.

Almost all external causes of death (e.g. suicides, accidents and assaults) are referred to a coroner.

Coroners are responsible for investigating reportable deaths. Although there is variation across jurisdictions, reportable deaths generally include:

• unexpected deaths with the cause of death unknown
• direct or indirect deaths from accident, injury or medical procedure – even with prolonged interval after the incident
• violent or unnatural deaths
• deaths where the person was 'held in care' or in custody immediately before they died (noting that ‘in care’ excludes facilities such as residential aged care)
• when a doctor has been unable to sign a death certificate giving the cause of death
• when the identity of the deceased is unknown.

Any changes in coroner referral patterns can affect counts of doctor certified deaths. Some conditions have higher coroner referral rates (ischaemic heart disease, cerebrovascular diseases and to a lesser extent, respiratory diseases and diabetes) so counts for those conditions would be more likely to be affected by such changes.

Each death registration in the national mortality dataset has 3 dates:

• date of occurrence – when the death happened
• date of registration – when it was officially registered
• date received by ABS – when it was included in national statistics.

Data in this report is based on date of occurrence.

Date of occurrence and date of registration will differ for all deaths, and the length of time by which they differ can vary considerably. Deaths are not reported to the ABS until they are registered, so the length of time between death and registration affects:

• the timeliness of information reported
• the ability to measure true change in mortality over time. 

The average time lag between death and registration can vary, although in general, deaths certified by a doctor are registered sooner. Coroner certified deaths undergo extensive investigative processes which can delay registration times and conclusions regarding the cause of death. Data regarding causes of death in this publication only includes deaths certified by a doctor. Data regarding all-cause deaths will include both doctor and coroner certified deaths.

Data in this release is compiled by state or territory in which the death was registered. In most cases, the death is registered in the state in which it occurred. Data in Deaths, Australia and Causes of Death, Australia is compiled by the state or territory of usual residence of the deceased, regardless of where in Australia the death occurred and was registered.

Deaths occurring in other territories of Australia are included in the jurisdictional dataset in which they are registered. For example, any deaths occurring on Christmas Island are registered by the Western Australian Registry of Births, Deaths and Marriages and presented in Western Australian outputs. The only exception to this is Norfolk Island where deaths are registered by the Norfolk Island Regional Council. Deaths occurring on Norfolk Island are included in Australia totals only. A very small number of deaths occur on Norfolk Island each year. 

Deaths of persons usually resident overseas which occur in Australia are included in the state/territory in which their death was registered. 

Statistics in this release are provisional and will be subject to additional processes prior to being released as part of the annual Deaths and Causes of Death datasets. Changes may occur in:

• the number of deaths
• demographic variables
• certifier type
• causes of death. 

Counts of deaths in the annual Deaths, Australia and Causes of Death, Australia are considered final. Causes of death for coroner referred deaths are subject to a revisions process. Further information on this revisions process can be found in the Methodology for Causes of Death, Australia.

As registrations for deaths that occurred in previous reference periods are sent to the ABS, these will be counted against their date of occurrence. Therefore, each release will represent a more complete count of the number of deaths that occurred in that reference period. The ABS recommends using the latest release for the most up-to-date data. 

Data can be impacted by changes within one or more of the Registries of Births, Deaths and Marriages and therefore caution should be exercised when assessing week to week movements.

The causes of death selected in this publication for further analysis were based on their status as major causes of death in Australia, and with a high proportion certified by a doctor (as opposed to a coroner). The selected causes include:

• Respiratory diseases (J00-J99), which are further broken down into:
  • Influenza and pneumonia (J09-J18)
  • Pneumonia (J12-J18)
  • Chronic lower respiratory diseases (J40-J47)
• Cancer (C00-C97, D45, D46, D47.1 or D47.3-D47.5)
• Ischaemic heart disease (I20-I25)
• Other cardiac conditions (I26-I51)
• Cerebrovascular diseases (I60-I69)
• Dementia, including Alzheimer's Disease (F01, F03, G30, G31.0, G31.8)
• Diabetes (E10-E14).
• COVID-19 (U07.1, U07.2, U10.9).

The Census and Statistics Act 1905 provides the authority for the ABS to collect statistical information, and requires that statistical output shall not be published or disseminated in a manner that is likely to enable the identification of a particular person or organisation. This requirement may restrict access to data at a very detailed level.

Some data cells with small values have been randomly assigned to protect confidentiality. As a result some totals will not equal the sum of their components. Cells with 0 values have not been affected by confidentialisation. Refer to the footnotes for the tables where confidentialisation has been applied.

The International Classification of Diseases (ICD) is the international standard classification for epidemiological purposes and is designed to promote international comparability in the collection, processing, classification, and presentation of causes of death statistics. The classification is used to classify diseases and causes of disease or injury as recorded on many types of medical records as well as death records.

Currently the ICD 10th revision is used for Australian causes of death statistics. This version is a variable-axis classification, meaning it groups conditions not just by anatomical site but also by disease type.

ICD-10 categories include:

• epidemic diseases
• constitutional or general diseases
• local diseases by site
• developmental diseases
• injuries

For example, a systemic disease such as sepsis is grouped with infectious diseases; a disease primarily affecting one body system, such as a myocardial infarction, is grouped with circulatory diseases; and a congenital condition, such as spina bifida, is grouped with congenital conditions.

For further information and access to versions of the ICD, refer to WHO International Classification of Diseases (ICD).

Further guidance on how causes of death are certified is available in the Cause of death certification guide.

The World Health Organization’s Classification and Statistics Advisory Committee (CSAC) oversees updates to the ICD. Updates may include new codes, code deletions, revised coding instructions, and clarified terminology. The cumulative List of Official ICD-10 updates can be found online.

From the 2013 reference year, the ABS implemented a new automated coding system called Iris.

Data coded in the Iris system applies updated versions of the ICD-10 when coding multiple causes of death, and when selecting the underlying cause of death. Information on Iris and ICD-10 versioning can be found in the table below. For details of further impacts of this change from 2013 data onwards, see the ABS Implementation of the Iris Software: Understanding Coding and Process Improvements Technical note, in the Causes of Death, Australia, 2013 publication and Updates to Iris coding software: Implementing WHO updates and improvements in coding processes Technical note, in the Causes of Death, Australia, 2018 publication.