Here's a crude metric I use for gauging the relative goodness of societies as places to live: Immigration vs. emigration.
It's obviously fuzzy-- you can't get exact numbers on illegal migration, and the barriers (physical, legal, and cultural) to relocation matter, but have to be estimated. So does the possibility that one country may be better than another, but a third may be enough better than either of them to get the immigrants.
For example, the evidence suggests that the EU and the US are about equally good places to live.
I don't think that's a good metric. Societies that aren't open to mass immigration can have negligible numbers of immigrants regardless of the quality of life their members enjoy. Japan is the prime example.
Moreover, in the very worst places, emigration can be negligible because people can be too poor to pay for the ticket to move anywhere, or prohibited to leave.
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