zlacker

The latest population census in Russia was executed so horribly that demographics experts still rely on the 2010 and earlier ones to figure out the approximate population number (the difference between estimations is in ~10 million range). Of course the whole war, relocation, and undocumented immigration things aren't making things any easier.

Much easier to calculate population numbers in countries with a population register, but those are usually smaller countries like those in the Nordics. I don't think censuses are even held around here...?

>>Anonyn+(OP)
Those rely on a strong centralized government that can somehow penalize people for not keeping records up to date. Not necessarily by direct checks, but maybe via inconveniences caused by inaccuracies. They are probably using other data (aggregate statistics from health system, tax records, social services) to conduct cross checks.

A few years back in Austria there was a small scandal as a newly introduced government app to notify about changing residence was used by a member of parliament to declare they moved into the Parliament.