Introduction
Excess mortality is 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. It provides an indication of whether mortality was higher, lower or at expected levels during a given time period.
Historically, excess mortality methods have been used to assess the impacts of events such as acute respiratory diseases (e.g. influenza), heat waves or natural disasters. Most recently, excess mortality was the most common method used to measure the impact of COVID-19 on mortality trends across the world.
Excess mortality measures are most often produced at the all-cause level as they can account for differences in cause of death certification (e.g. a death due to "infectious exacerbation of emphysema would be attributed to a chronic respiratory disease if the infectious agent was not known, but attributed to influenza if this was known to cause the exacerbation) and deaths that are both directly and indirectly related to an event (e.g. patterns in access to health care may change during extreme events).
This publication presents weekly and annual excess mortality estimates for 2024 and 2025 for Australia and the states and territories.
It is the first publication produced by the ABS where excess mortality estimates are measuring expected mortality in the current health context, i.e. where COVID-19 is included alongside other diseases, conditions and external causes as a persistent contributor to deaths in Australia.
The ABS has applied a new statistical model (Generalised Additive Model) to produce expected mortality estimates to inform this updated approach. More information can be found in the methodology.
Excess mortality estimates produced in this publication cannot be compared to estimates published for 2020-2023 as they are addressing two different research questions as outlined below.