Computing years of lost life: why actuaries really need to be able to do counterfactual reasoning

Hugh Osmond recently put out this interesting twitter thread:

Although the average age of death in the UK is around 82, if a person reaches 82 then on average (i.e. without knowing any details of the particular person) the person can expect to live about another 8 years. We know the average age of a person dying from Covid is also 82, so it seems reasona…