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Now as we know, the vaults were built not only as a savour to humanity, but to exicute social experiments.
But who is using this data? Who is quantifying it? Really if there was no one to make use of the end results, then what was the point?

"The shadow government, the Enclave, responsible for the experiment (officially known as the "Societal Preservation Program"), have considered themselves prime candidates for recolonizing the world after a nuclear holocaust and to this end commissioned the construction of their own shelters, isolated from the Vault network. The purpose of the Vault experiments was to help prepare the Enclave for either re-colonizing Earth or colonizing another planet if Earth turned out to be uninhabitable by non-irradiated humans.

Of the 122 Vaults, only 17 were control, meaning that only 17 were made to public expectations, all others were designed to include a social experiment, sometimes with a select few of the inhabitants observing the occupants.

The few Vaults that survived intact for more than 80 years came to serve another, unanticipated purpose: they were an excellent source of pure human stock, uncontaminated by the mutated airborne strain of FEV and prime candidates for conversion into super mutants."
[Source]


Overview... Enclave to blame, they did it to make a "better" world for themselves. However, karma got back at them I guess.

Vault 101 was a control vault. No experiment there.

i wonder how people in other country's survived?

I'm not from the US so 'd like to know that as well!
And yeah a Fallout game set in say the UK (were I live xp ) would be awesome as I'd atleast know the landmarks!

or at lest a add on

Indefinite yes, but to test the Overseers capabilities of keeping a closed community. "The main purpose was to never give the 'all clear' signal, and keep the vault closed indefinitely". However, it was one of the 17 vaults made to public expectations.

It still acted as a control, in the sense that the people themselves were not pitted against each other, were not used for experiments, victims of a secret project gone bad, etc...

We saw how that whole thing turned out, didn't we?

As explained in Fallout 2, that was due to a shipping error and was not a planned experiment. Vault 8 (of Vault City) received more water chips than they needed while Vault 13 in turn received an extra G.E.C.K. that was intended for Vault 8... This error actually gave the Enclave a unexpected benefit as they had both pure and mutated "stock" from the same source and could therefore better study the effects of mutations on a genetic level and used this knowledge to created the "improved" F.E.V. that was later used as an ending choice in Bethesda's FO3...