Germany (as one example) has a social expenditure of 25% versus USA at 19%[0]. Switzerland is 19.4%.

[0] https://stats.oecd.org/Index.aspx?DataSetCode=SOCX_AGG

Using social expenditure in % of GDP to measure its "cost-effectiveness" is problematic, as there's wide agreement social spending has a big impact on GDP. (Structure of the spending is the other big variable of course)

It's not just how much, it's also what, who, how, where, and why.

The Nordics are awkward examples if you follow their trajectory back to the 70s, with periods of socialization and liberalization in the mix:

http://www.cityam.com/article/1394655511/forget-nordic-socia...

We pretend there are clean examples, but everything is pretty messy, and we rarely get any pure test cases for any economic philosophy.

Macro is black arts. "Avoid price controls" and "don't print boatloads of money" seem like reasonable guidelines. Beyond that, who knows? Corruption's bad but hard to stop. Moving risk around is (sometimes)* bad but hard to stop. Shrug and try not to do anything too extreme.

* Insurance is a beneficial example.