[arjie]

What an interesting question. It would seem intuitively that a population with a limited band of socioeconomic mobility must answer 10 and one with a wide band of mobility must answer 0. I wonder whether that is true.

[Doxin]

As far as I can tell happiness is relative in any case, I'm not sure that accounting for that in the question is a bad thing.

[M95D]

And yet, highest rating countries also have good socioeconomic mobility.

Socioeconomic mobility isn't the only thing that affects happiness. A good wife/husband contributes a lot to happiness, for example.