Measuring excess mortality: a guide to the main reports
A guide to the major publications related to excess deaths in the UK, who produces them and links to the methods and analysis.
Excess deaths can be defined as the difference between the actual number of deaths in a particular period and the estimated number of deaths expected in that period. Expected deaths can be derived in a variety of ways for different purposes, which means that there may be different estimates of excess deaths published by different organisations and used for those specific purposes.
This document explains the major publications related to excess deaths in the UK. Details of the methodologies are published by individual organisations.
Producers and publishers of the main reports
The Office for National Statistics (ONS) is responsible for collecting, analysing and disseminating statistics about the UK’s economy, society and population. As such, ONS produces statistics related to the registration of life events which includes publication of Deaths registered weekly in England and Wales. National Records of Scotland (NRS) and Northern Ireland Statistics and Research Agency (NISRA) are responsible for mortality outputs for Scotland and Northern Ireland, respectively.
The Office for Health Improvement and Disparities (OHID) forms part of the Department of Health and Social Care (DHSC) and is responsible for work to improve the nation’s health and reduce health disparities. OHID produces the monthly publication Excess mortality within England: post-pandemic method.
The UK Health Security Agency (UKHSA) is responsible for surveillance of infectious diseases and other health related threats to the security of the nation’s health. UKHSA currently produces 3 excess mortality related products: Weekly all-cause mortality surveillance in England, Annual heat mortality monitoring in England and Annual surveillance of influenza and other seasonal respiratory viruses in the UK.
ONS reports
Deaths registered weekly in England and Wales
The Deaths registered weekly in England and Wales publication includes estimates of excess all-cause mortality in England and Wales.
On 20 February 2024, ONS published a new method for measuring excess mortality that will allow national comparisons of excess deaths. In the future, the weekly publication will include numbers of death registrations and excess deaths for each of the 4 UK countries as well as the UK as a whole. Therefore, this publication will contain the headline figures for England and will be the most appropriate for making comparisons across each of the devolved administrations of the UK.
NRS and NISRA currently produce excess mortality figures for Scotland and Northern Ireland, respectively, and have updated their methodology in line with that implemented by ONS. This means a consistent method is used by all 4 nations, which enables comparisons at national level.
ONS’s new methodology for estimating the expected number of deaths, which replaces the previous 5-year average approach, is closely aligned with OHID’s updated methodology described below. Both organisations publish estimates of excess deaths for England. Those produced by ONS are consistent with estimates for other UK countries, while those produced by OHID can be disaggregated by local authorities within England (at present, ONS’s new methodology permits only regional breakdowns in England).
OHID reports
Excess mortality within England: post-pandemic method
OHID produces monthly estimates of excess mortality within England. OHID published this revised version of its report on 20 February 2024. This new analysis and methodology will be aligned with ONS’s new method where possible.
Rather than measuring the impact of the COVID-19 pandemic on mortality, the new approach provides a method for ongoing monitoring which includes an updated baseline period. These estimates represent the number of deaths above the number expected, based on trends in mortality over the previous 5 years instead of comparing to the pre-pandemic period. Further details are captured in ’Changes to OHID’s reporting of excess mortality in England’ (published alongside the report).
This publication is the most appropriate to use when comparing excess mortality within England. OHID produces breakdowns which show inequalities in levels of excess mortality, including by sex, age group and level of deprivation for the English regions and local authorities. OHID’s analysis by cause of death describes which causes are particularly contributing to excess deaths in specific time periods.
OHID’s monthly publication provides estimated numbers of excess deaths and the ratio of registered to expected deaths. Users can adjust the time periods presented, allowing cumulative estimates to be shown for specific periods.
UKHSA reports
Weekly all-cause mortality surveillance in England
All-cause mortality surveillance shows time periods when mortality levels were higher than expected, rather than providing an estimate of the number of actual or expected deaths. The weekly all-cause mortality surveillance reports are published every Thursday.
This publication includes details of the weeks in which observed deaths are higher than an expected threshold, which is calculated using a European-wide algorithm called Euromomo. It includes a chart of observed and expected deaths by the date the death occurred across all ages in England. The chart also shows the upper limit for when the number of deaths is considered to be significantly higher than expected.
This publication can be used for making international comparisons and for other surveillance purposes, prompting further investigation to determining the cause, and assessing the impact of known health events. Health events could include high levels of influenza, extreme heat or extreme cold, for example.
Annual heat mortality monitoring in England
The heat mortality monitoring reports are published yearly during the summer season in the following year.
During episodes of heat in the summer months, UKHSA estimates the number of deaths caused by the heat using the baseline death registration data from the General Register Office (GRO). Heat episodes are defined as any day on which an amber Heat-Health Alert (HHA) is issued in at least one region, or the mean central England temperature is at least 20°C. One day either side of the alert or mean temperature is also included to allow for the time-lagged effects of temperature on mortality. Where episodes overlap, they are counted as one episode. The data is stratified by NHS England region, age group and heat period. Future publications will also include sex and years of life lost.
The publication includes a plotted graph for those aged 65 years and over of daily all-cause excess mortality and heat-attributable mortality in England. An additional plot compares the total all-cause excess mortality estimates using observed deaths and modelled excess all-cause mortality by heat episode and total estimate across all episodes in England.
UKHSA’s heat mortality monitoring provides information on excess deaths observed during episodes of heat each year to inform public health actions. It also provides information to the public on the observed impacts from heat on health. The publication also serves as a basis to update the Weather-Health Alerts (WHA) temperature thresholds.
Annual surveillance of influenza and other seasonal respiratory viruses in the UK
The surveillance of influenza and other seasonal respiratory viruses in the UK statistics are published every year after the winter period.
This publication includes estimates of the number of deaths attributable to influenza, COVID-19 and extreme cold using all-cause mortality data.
This publication can be used to indicate the potential mortality burden from COVID-19, other respiratory diseases and extreme cold.