I don't know about correlation between average IQ and a country/state performance (e.g. GPD performance capita) but there is plenty of research that show correl

I don't know about correlation between average IQ and a country/state performance (e.g. GPD performance capita) but there is plenty of research that show correlation between a person's IQ and expected income/wealth. It's also intuitive. The whole path to college, at least for hard sciences, partially select for IQ. And college education correlates with higher income.