My problem with IQ is that it's no more than a somewhat dubious statistical construct. The idea is that we know that people who do well in tests for one of a particular set of skills tend to do pretty well in tests for some other skills in the same set of tests, and the theory is that there's some sort of measurable meta-ability, Intelligence, that manifests itself in the various discrete skills measured in the different tests.
That's all well and good, though I'm not qualified to comment on the statistics behind the theory, but the idea of then trying to correlate something else with the statistical construct, when there are necessarily going to be so many other factors involved seems to me completely fanciful, so I'm never sure what IQ tests measure other than your ability to do IQ tests.
I last took an IQ test when I was 10, as part of the (highly competitive) entrance tests for the secondary school I attended. I assume I must have done pretty well, since they gave me a scholarship, but ever since then people were more interested in what I knew about English, history, Latin, maths, physics, French and so on, and later, in my degrees and professional qualifications, and after that in my work record.
How do you separate out, in all that, the role played by IQ in my later life from the roles played by the quality of the education I received, the nature of my family life, financial circumstances, general good health, and so on?