Why would the OECD dataset show such different numbers from the OWID and WHO datasets?
(Note: WHO’s dataset hasn’t been updated for 2022, so I’ll focus on OWID from here on out.)
OECD fails to consider all Swedish deaths
After a lot of cross-checking, I noticed one straightforward issue with the OECD data. While they correctly and precisely copy weekly deaths as reportedby the Swedish government, they fail to consider deaths which were not classified with any week.
As OWID notes in their methodology:
“Sweden has a significant number of deaths which occurred in an “unknown” date (and thus week) in all years. However, 95% these have a known month of death.”
So OWID reasonably assigns those deaths to weeks within the month that they happened. It’s not perfect (it can’t be, since the exact date isn’t known) but it seems much better than ignoring such deaths.
I applied that change to OECD’s dataset, and doing so causes their estimate to rise — eliminating about half of the gap between excess mortality predictions.
In the below graph, the dark blue OCED line would rise to the light-blue line: