FOI Ref: FOI/2022/4002
You asked
You have released a dataset about Deaths occurring between 1 January and 31 December 2021 here: https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/datasets/deathsbyvaccinationstatusengland
In your methodology article https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/methodologies/weeklycovid19agestandardisedmortalityratesbyvaccinationstatusenglandmethodology you state that ASMR is based on the ESG, death rate and population for an age group. You have a column for the "Number of deaths" but not population.
Please supply the population sizes used for all data in this dataset or at least for: "Table 7: Monthly age-standardised mortality rates by age-group and vaccination status for all deaths, per 100,000 person-years, England, deaths occurring between 1 January 2021 and 31 December 20211,2,3,4,5,6,7,8,9,10,11"
Please supply the size of the population per age group per vaccination status per month.
We said
Thank you for your enquiry.
The population used to calculate the age-standardised mortality rates (ASMRs) in Deaths by vaccination status, deaths occurring between 1 January and 31 December 2021 is given in person-years in the relevant tables of the dataset. Person-years are used, rather than population, because the population in each vaccination status group will change over the month as people get vaccinated and the same person may contribute to multiple vaccination status groups. Therefore, it is not possible to give a number of people in each vaccination status group used to calculate the rates for the month, as this is not involved in the methodology used for this analysis.
Person-years take into account both the number of people and the time spent in each vaccination status. For example, 2 people for 3 months each in a particular vaccination state is equivalent to 0.25 times 2 = 0.5 person-years.
For the previously published weekly rates, and the accompanying methodology article, the population on the last day of the week in each vaccination status group was used to calculate the rates, as there is less change over a week than a month. The methodology is the same for the monthly rates except that the population is given in person-years.
It is not possible to provide the data requested as the population by vaccination status is not fixed in a particular month.