I.Q. predicts income and educational achievement (things which, I hope we can agree, are indicators of intelligence) better than parental socioeconomic status. Not only that, but I.Q. is the best predictor of educational level, occupational level and income level (again, more indications of intelligence). Surprisingly, I.Q. even beats 'grades' as a predictor of educational level. The average sample size for the groups is approximately 97,000:
I think IQ is an excellent indicator of intelligence, I don't know about the whole educational level or occupational level corresponding to intelligence. Maybe I'm biased because I am a bit of an outlier. When I would take the more reliable IQ tests in school and by several psychologists who wondered what the fuck was wrong with me, I would usually score between 160 and 165. I usually don't mention the number publicly and I certainly would never tell anybody in my offline life what it is. Here the worst you can do is doubt me or call me a liar. In my personal life it can intimidate people for whatever reason.
My educational level is probably the lowest on the site. 9th grade is my highest level of education. I had to drop out of school to raise my siblings who I got custody of when I was emancipated at 16. I always have panic attacks when I start rapidly rising the ranks at work, and quit in a way that ensures I burn all my bridges. So I'm at a job only making 50,000 a year. I get the feeling that most the people visiting this site either make 6 figures or will shortly after finishing school.
Granted, I was despite the high IQ also considered learning disabled as a kid, but how exactly does a 165 IQ lead to never making it past the 9th grade and never achieving even mediocre financial success? I know some of my bosses have to have like 2 digit IQs as well by how they run their business, so high IQ is certainly not correlated with their positions.