FOI reference: FOI-2025-2511
You asked
I have been doing some research on excess deaths since Covid-19 and noticed that the way excess deaths are registered has changed.
Does this not set the baseline for excess deaths at a new high, suggesting a new ‘baseline’ since 2019?
Also have I got my figures correct as to think in the whole of 2018-2019 winter there was 23,200 excess deaths? And in one week ending 13 December 2024, 11,950 were registered in one week alone? (Both figures are for England and Wales).
We said
In February 2024 we introduced a new method for estimating the number of excess deaths, replacing the use of five-year averages. The number of expected deaths is now estimated using statistical models that account for changes in population size and age structure, and trends in mortality over time. Excess deaths are then calculated by subtracting the number of expected deaths from the observed deaths in a given period.
Figure 1 in the article 'Estimating excess deaths in the UK, methodology changes: February 2024' , shows how weekly estimates of excess deaths differ between the new method and the previously used five-year average from 2011 to 2019. Figure 2 in the article provides a comparison of the estimates from 2020 to the end of 2023. The new method is now used to report excess deaths on a weekly basis in our 'Deaths registered weekly in England and Wales' statistical bulletin.
We previously estimated excess winter mortality by comparing the winter months of December to March with the average of the four-month periods before and after. This data was published annually in our Winter mortality in England and Wales release. Following the Health and Social Care Statistical Outputs consultation commissioned by the Health and Social Care Statistics Leadership Forum, we are improving some of our statistical products. For 'Winter mortality in England and Wales', produced by ONS, there was a proposal to undergo a review, with particular focus on methodology and timeliness of the statistics. To enable this review to take place, this publication has been paused, which means the release covering the winter 2022 to 2023 containing provisional deaths, and 2021 to 2022 using final deaths will not be published. A proposal on the future status on this output will be determined following this review and the outcome of the cross-government technical working group who are currently reviewing methods for excess deaths statistics.
Using the provisional estimates from the 'Excess winter mortality in England and Wales' release, you are correct that in 2018-19 it was estimated that 23,200 excess winter deaths occurred in England and Wales.\ We have not produced excess winter deaths using our new methodology.
There were 11,951 deaths registered in England and Wales in the week ending 13 December 2024 (the total number of deaths for this week has been refreshed since we published on 8 January 2025). However, using estimates from our new model we would have expected there to be 13,086 deaths registered in that week. In that case, there were 1,135 fewer deaths than expected.